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  1. 50 CFR 14.23 - Live farm-raised fish and farm-raised fish eggs.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Live farm-raised fish and farm-raised fish eggs. 14.23 Section 14.23 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF... Exportation at Designated Ports § 14.23 Live farm-raised fish and farm-raised fish eggs. Live farm-raised fish...

  2. Biofilm responses to marine fish farm wastes

    Energy Technology Data Exchange (ETDEWEB)

    Sanz-Lazaro, Carlos, E-mail: carsanz@um.es [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100 Murcia (Spain); Navarrete-Mier, Francisco; Marin, Arnaldo [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100 Murcia (Spain)

    2011-03-15

    The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems. - Research highlights: > Biofilms can act as a trophic pathway of fish farm dissolved wastes. > Biofilms are reliable tools for monitoring fish farm dissolved wastes. > The influence of the fish farm dissolved wastes can be detected 120-350 m from farm. - Under the influence of fish farming biofilm accumulates organic carbon, nutrients, selenium and metals, regardless of the structure and trophic niche of the community.

  3. Biofilm responses to marine fish farm wastes

    International Nuclear Information System (INIS)

    Sanz-Lazaro, Carlos; Navarrete-Mier, Francisco; Marin, Arnaldo

    2011-01-01

    The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems. - Research highlights: → Biofilms can act as a trophic pathway of fish farm dissolved wastes. → Biofilms are reliable tools for monitoring fish farm dissolved wastes. → The influence of the fish farm dissolved wastes can be detected 120-350 m from farm. - Under the influence of fish farming biofilm accumulates organic carbon, nutrients, selenium and metals, regardless of the structure and trophic niche of the community.

  4. Fish farm management practices in Nigeria | Omitoyin | African ...

    African Journals Online (AJOL)

    Fish farming can contribute significantly to national food security; alleviate malnutrition and poverty. However, its potential is yet to be fully tapped. Higher productivity in fish farming can be achieved through proper farm management. No matter how well constructed a fish farm is, without adequate management the farmer ...

  5. Occurrence of Flavobacterium psychrophilum in fish-farming environments

    DEFF Research Database (Denmark)

    Madetoja, J.; Dalsgaard, Inger; Wiklund, T.

    2002-01-01

    Occurrence of Flavobacterium psychrophilum in fish farms and fish-farming environments was studied using agar plate cultivation,the immunoflourescence antibody technique (IFAT) and nested PCR. Characteristics of 64 F. psychrophilum isolates from rainbow trout Oncorhynchus mykiss, fish farm rearing....... F. psychrophilum was detected and isolated from skin mucus, skin lesions and internal organs of diseased rainbow trout and from fish without clinical disease. The pathogen was also present in wild perch Perca fluviatilis, roach Rutilus rutilus, and ovarian fluids of farmed rainbow trout brood fish...... ribopatterns), ribotype A was the most dominant. Farmed rainbow trout brood fish carried a broad-spectrum of serologically and genetically different F. psychrophilum in ovarian fluids. Virulence of the tested isolates in rainbow trout varied and naturally infected rainbow trout shed 104 to 108 cells fish-1 h-1...

  6. Wild-Caught Versus Farmed Fish – Consumer Perception

    Directory of Open Access Journals (Sweden)

    Tomić Marina

    2017-06-01

    Full Text Available We have limited knowledge of determinants of consumer preferences for wild-caught versus farmed-raised fish, so this work aims to investigate the impact of sociodemographics, habits and frequency of fresh fish consumption, such as involvement in cooking, on the preferences for wild versus farmed fish. A survey was done on a sample of 1151 fish consumers in Croatia. Results showed that female, older consumers, consumers with higher income and those living in coastal parts of Croatia give higher preferences for wild fish and they detect differences between the taste of wild and farmed fish. Consumers with higher levels of habits of fresh fish consumption, who eat fresh fish often and are more involved in cooking, prefer wild-caught fish. These findings provide valuable information for the aquaculture sector, especially for planning marketing strategies for the promotion of farmed fish.

  7. Fish consumption behavior and fish farming attitude in Kingdom of Saudi Arabia (KSA

    Directory of Open Access Journals (Sweden)

    Abdul Qader Khan

    2018-04-01

    Full Text Available This study aimed to explore fish consumption behavior and fish farming attitude of the Saudi households in the Kingdom of Saudi Arabia (KSA. The survey was conducted in Sharurah town situated in Najran province. The data were collected through a well-structured questionnaire from 100 respondents residing in the province. Pearson Correlation Coefficient was used to see the significant and non-significant impact of the two variables. The results showed that majority (37% of the respondents fell in the age group of 25–34 and majority (35% of the respondents have high level of education i.e. up to university level. The results also depicted that majority (31% of the people consume fish and were aware of the nutritional value of fish. However, majority (85% of the respondents were not satisfied by the fish price. The results further indicated that none of the respondent was engaged in fish farming activity i.e. they had no fish farms at their homes. Furthermore, majority (83% respondents had no intentions to start fish farming at their homes in future. The study concludes that fish consumption and preference is high in the study area and people prefer fish more than chicken and meat for consumption purposes because of their knowledge regarding the nutritional value of fish. However, the age and educational level have negative impact on the respondent’s opinion about fish price in the study area. The study recommends that proper policies should be formulated to educate people about fish farming (aquaponics and its importance through fisheries extension services to enhance the interest of people in fish farming. Keywords: Fish consumption, Fish farming, Attitude, Intentions, Saudi Arabia, Aquaponics

  8. Prevalence of fish diseases in fish farms in Katsina State, Nigeria ...

    African Journals Online (AJOL)

    Prevalence of fish disease in fish farms in Nigeria was investigated using data from structured questionnaire obtained during farm visits, and analysed using descriptive statistics and multiple linear regression. Findings from the study revealed that majority of the farm manager's (45.7) have less than 3 years of experience in ...

  9. Effect of fish farming on household food security in western Kenya ...

    African Journals Online (AJOL)

    This study examined the impact of fish farming on household food security and livelihoods of fish farming and non-fish farming households in Siaya County. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. Currently fish farming remains under developed in Western Kenya where pond ...

  10. Fish benefits from offshore wind farm development

    DEFF Research Database (Denmark)

    Leonhard, Simon B.; Stenberg, Claus; Støttrup, Josianne

    2013-01-01

    The studies up until 2006 showed few effects on the fish fauna that could be attributed to the establishment and operation of the wind farms. Fish abundance and diversity were not higher inside the wind farms than in the areas outside the wind farms. One obvious reason for this could be that the ...

  11. The Resistome of Farmed Fish Feces Contributes to the Enrichment of Antibiotic Resistance Genes in Sediments below Baltic Sea Fish Farms.

    Science.gov (United States)

    Muziasari, Windi I; Pitkänen, Leena K; Sørum, Henning; Stedtfeld, Robert D; Tiedje, James M; Virta, Marko

    2016-01-01

    Our previous studies showed that particular antibiotic resistance genes (ARGs) were enriched locally in sediments below fish farms in the Northern Baltic Sea, Finland, even when the selection pressure from antibiotics was negligible. We assumed that a constant influx of farmed fish feces could be the plausible source of the ARGs enriched in the farm sediments. In the present study, we analyzed the composition of the antibiotic resistome from the intestinal contents of 20 fish from the Baltic Sea farms. We used a high-throughput method, WaferGen qPCR array with 364 primer sets to detect and quantify ARGs, mobile genetic elements (MGE), and the 16S rRNA gene. Despite a considerably wide selection of qPCR primer sets, only 28 genes were detected in the intestinal contents. The detected genes were ARGs encoding resistance to sulfonamide ( sul1 ), trimethoprim ( dfrA1 ), tetracycline [ tet(32), tetM, tetO, tetW ], aminoglycoside ( aadA1, aadA2 ), chloramphenicol ( catA1 ), and efflux-pumps resistance genes ( emrB, matA, mefA, msrA ). The detected genes also included class 1 integron-associated genes ( intI1, qacE Δ 1 ) and transposases ( tnpA ). Importantly, most of the detected genes were the same genes enriched in the farm sediments. This preliminary study suggests that feces from farmed fish contribute to the ARG enrichment in farm sediments despite the lack of contemporaneous antibiotic treatments at the farms. We observed that the intestinal contents of individual farmed fish had their own resistome compositions. Our result also showed that the total relative abundances of transposases and tet genes were significantly correlated ( p = 0.001, R 2 = 0.71). In addition, we analyzed the mucosal skin and gill filament resistomes of the farmed fish but only one multidrug-efflux resistance gene ( emrB ) was detected. To our knowledge, this is the first study reporting the resistome of farmed fish using a culture-independent method. Determining the possible sources of

  12. A floating trap for sampling downstream migrant fishes.

    Science.gov (United States)

    Carl E. McLemore; Fred H. Everest; William R. Humphreys; Mario F. Solazzi

    1989-01-01

    Fishery scientists and managers are interested in obtaining information about downstream movements of fish species for biological and economic reasons. Different types of nets and traps have been used for this purpose with only partial success. The floating, self-cleaning downstream migrant trap described here proved successful for sampling several salmoniform and...

  13. Coping styles in farmed fish: consequences for aquaculture

    DEFF Research Database (Denmark)

    Castanheira, Maria Filipa; Conceição, Luís E.C.; Millot, Sandie

    2017-01-01

    Individual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present...... in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies have demonstrated links to performance traits, health and disease susceptibility and welfare. This study...... will review (i) the main behavioural, neuroendocrine, cognitive and emotional differences between reactive and proactive coping styles in farmed fish; (ii) the methodological approaches used to identify coping styles in farmed fish, including individual (group) mass-screening tests; and (iii) how knowledge...

  14. Matching breeding goals with farming systems to enhance the sustainability of fish farming

    NARCIS (Netherlands)

    Besson, Mathieu

    2017-01-01

    Fish farming is growing but is also facing challenges regarding economic viability and environmental sustainability. Selective breeding could enhance the sustainability of fish farming by changing animal performances. Thus, our aim was to develop sustainable breeding goals by using economic (EV)

  15. Differential response of fish assemblages to coral reef-based seaweed farming.

    Directory of Open Access Journals (Sweden)

    E James Hehre

    Full Text Available As the global demand for seaweed-derived products drives the expansion of seaweed farming onto shallow coral ecosystems, the effects of farms on fish assemblages remain largely unexplored. Shallow coral reefs provide food and shelter for highly diverse fish assemblages but are increasingly modified by anthropogenic activities. We hypothesized that the introduction of seaweed farms into degraded shallow coral reefs had potential to generate ecological benefits for fish by adding structural complexity and a possible food source. We conducted 210 transects at 14 locations, with sampling stratified across seaweed farms and sites adjacent to and distant from farms. At a seascape scale, locations were classified by their level of exposure to human disturbance. We compared sites where (1 marine protected areas (MPAs were established, (2 neither MPAs nor blast fishing was present (hence "unprotected", and (3 blast fishing occurred. We observed 80,186 fish representing 148 species from 38 families. The negative effects of seaweed farms on fish assemblages appeared stronger in the absence of blast fishing and were strongest when MPAs were present, likely reflecting the positive influence of the MPAs on fish within them. Species differentiating fish assemblages with respect to seaweed farming and disturbance were typically small but also included two key target species. The propensity for seaweed farms to increase fish diversity, abundance, and biomass is limited and may reduce MPA benefits. We suggest that careful consideration be given to the placement of seaweed farms relative to MPAs.

  16. Differential response of fish assemblages to coral reef-based seaweed farming.

    Science.gov (United States)

    Hehre, E James; Meeuwig, J J

    2015-01-01

    As the global demand for seaweed-derived products drives the expansion of seaweed farming onto shallow coral ecosystems, the effects of farms on fish assemblages remain largely unexplored. Shallow coral reefs provide food and shelter for highly diverse fish assemblages but are increasingly modified by anthropogenic activities. We hypothesized that the introduction of seaweed farms into degraded shallow coral reefs had potential to generate ecological benefits for fish by adding structural complexity and a possible food source. We conducted 210 transects at 14 locations, with sampling stratified across seaweed farms and sites adjacent to and distant from farms. At a seascape scale, locations were classified by their level of exposure to human disturbance. We compared sites where (1) marine protected areas (MPAs) were established, (2) neither MPAs nor blast fishing was present (hence "unprotected"), and (3) blast fishing occurred. We observed 80,186 fish representing 148 species from 38 families. The negative effects of seaweed farms on fish assemblages appeared stronger in the absence of blast fishing and were strongest when MPAs were present, likely reflecting the positive influence of the MPAs on fish within them. Species differentiating fish assemblages with respect to seaweed farming and disturbance were typically small but also included two key target species. The propensity for seaweed farms to increase fish diversity, abundance, and biomass is limited and may reduce MPA benefits. We suggest that careful consideration be given to the placement of seaweed farms relative to MPAs.

  17. Economic Situation of Fish Farming in Southeastern Coast of the Black Sea

    Directory of Open Access Journals (Sweden)

    Ştefan Mihai Petrea

    2012-10-01

    Full Text Available Aquaculture industry, like most other industries, has a very powerfull correlation with the economical domain. Being an economic activity that generates profit, practicing fish farming aims profit maximization. The present study gives information regarding the economical indicators and also makes a cost structure analysis of five groups of fish farms from Southeastern Coast of the Black Sea: homestead fish farms, small scale fish farms, middle scale fish farms, big scale fish farms and floating cages. The fish farms were classified in this way by their production capacity. In order to collect data, the most representative fish farms for each group were selected and face to face interviews were made for every one of them. Data related to their source of financing, initial investment, labour costs, selling prices, feed costs and other operational costs were collected, arranged, structured and analyzed and a series of economic indicators as gross production value, gross margin, breakeven quantity, specific investment, profit, profitability ratio, rate of return or labour productivity were calculated. As a result, it was observed that fish production capacity has a big influence over the rate of return, middle scale fish farms being the most profitable, followed closely by small scale fish farms.

  18. Common fish diseases and parasites affecting wild and farmed ...

    African Journals Online (AJOL)

    Intensification of aquaculture production in Uganda is likely to result into disease out-breaks leading to economic losses to commercial fish farms and associated natural aquatic ecosystems. This survey assessed health profiles of selected commercial fish farms and adjacent natural aquatic ecosystemsto identify fish ...

  19. Aggregations of bluefish Pomatomus saltatrix (L.) at Mediterranean coastal fish farms: seasonal presence, daily patterns and influence of farming activity

    OpenAIRE

    Arechavala-Lopez, Pablo; Izquierdo-Gomez, David; Uglem, Ingebrigt; Sanchez-Jerez, Pablo

    2014-01-01

    Bluefish, Pomatomus saltatrix (Linnaeus, 1766), is commonly observed close to Mediterranean open-sea fish farms. It usually preys on wild fish that are attracted to farms, but also on farmed fish by biting holes in sea cages net walls. In the current telemetry study, we found that the tagged bluefish stayed close to fish farms during spring and early summer. However, most of the tagged fish disappeared from the farms during autumn, when the sea water temperature dropped. When aggregating at f...

  20. Proxy measures of fitness suggest coastal fish farms can act as population sources and not ecological traps for wild gadoid fish.

    Directory of Open Access Journals (Sweden)

    Tim Dempster

    Full Text Available BACKGROUND: Ecological traps form when artificial structures are added to natural habitats and induce mismatches between habitat preferences and fitness consequences. Their existence in terrestrial systems has been documented, yet little evidence suggests they occur in marine environments. Coastal fish farms are widespread artificial structures in coastal ecosystems and are highly attractive to wild fish. METHODOLOGY/PRINCIPAL FINDINGS: To investigate if coastal salmon farms act as ecological traps for wild Atlantic cod (Gadus morhua and saithe (Pollachius virens, we compared proxy measures of fitness between farm-associated fish and control fish caught distant from farms in nine locations throughout coastal Norway, the largest coastal fish farming industry in the world. Farms modified wild fish diets in both quality and quantity, thereby providing farm-associated wild fish with a strong trophic subsidy. This translated to greater somatic (saithe: 1.06-1.12 times; cod: 1.06-1.11 times and liver condition indices (saithe: 1.4-1.8 times; cod: 2.0-2.8 times than control fish caught distant from farms. Parasite loads of farm-associated wild fish were modified from control fish, with increased external and decreased internal parasites, however the strong effect of the trophic subsidy overrode any effects of altered loads upon condition. CONCLUSIONS AND SIGNIFICANCE: Proxy measures of fitness provided no evidence that salmon farms function as ecological traps for wild fish. We suggest fish farms may act as population sources for wild fish, provided they are protected from fishing while resident at farms to allow their increased condition to manifest as greater reproductive output.

  1. The Implications of Ranaviruses to European farmed and wild freshwater fish

    DEFF Research Database (Denmark)

    Jensen, Ann Britt Bang

    The present thesis explores the implications of ranaviruses to European farmed and wild freshwater fish. The work presented was carried out as a part of the EU project “Risk assessment of new and emerging systemic iridoviral diseases for European fish and aquatic ecosystems” which was initiated...... in 2005 as a reaction to the speculation that ranaviruses might pose a serious threat to both farmed and wild-living freshwater fish and amphibians within the European community. In the present thesis, the purpose is to determine the implications of ranaviruses to European freshwater farmed and wild...... describing the risk of introduction and spread of exotic ranaviruses in European wild and farmed aquatic ecosystems Objectives 1 and 2 have been addressed by experimental trials involving bath challenges of both European farmed and wild fish species and ornamental fish species. The results showed that some...

  2. Consumer perception versus scientific evidence of farmed and wild fish

    DEFF Research Database (Denmark)

    Verbeke, Wim; Sioen, Isabelle; Brunsø, Karen

    2007-01-01

    . Primary data were collected through a consumer survey (April 2003) and focus group discussions (May 2004) with Belgian consumers. The majority of the consumer sample reported no perceived differences between farmed versus wild fish. However, mean perception scores were slightly in favour of wild fish......The increasing number of marketable fish being supplied from aquaculture is a response to the increasing demand for healthy food and is filling the gap left by depleting natural fish stocks. Little is known about the awareness and perception of the consumer in terms of farmed fish versus fish from...... capture fisheries. The consumer's subjective point of view is of overriding importance for the production system and product acceptance as well as for future market success. In this paper consumer perception in Belgium is explored and compared against scientific evidence of farmed versus wild fish...

  3. Farm-level risk factors for fish-borne zoonotic trematode infection in integrated small-scale fish farms in northern Vietnam.

    Directory of Open Access Journals (Sweden)

    Van Thi Phan

    Full Text Available BACKGROUND: Northern Vietnam is an endemic region for fish-borne zoonotic trematodes (FZT, including liver and intestinal flukes. Humans acquire the FZT infection by eating raw or inadequately cooked fish. The production of FZT-free fish in aquaculture is a key component in establishing a sustainable program to prevent and control the FZT transmission to humans. Interventions in aquaculture should be based on knowledge of the main risk factors associated with FZT transmission. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal study was carried out from June 2006 to May 2007 in Nam Dinh province, Red River Delta to investigate the development and risk factors of FZT infections in freshwater cultured fish. A total of 3820 fish were sampled six times at two-month intervals from 96 fish farms. Logistic analysis with repeated measurements was used to evaluate potential risk factors based on information collected through questionnaire interviews with 61 fish farm owners. The results showed that the FZT infections significantly increased from first sampling in June to July 2006 (65% to sixth sampling in April to May, 2007 (76%. The liver fluke, Clonorchis sinensis and different zoonotic intestinal flukes including Haplochis pumilio, H. taichui, H. yokogawai, Centrocestus formosanus and Procerovum varium were found in sampled fish. Duration of fish cultured (sampling times, mebendazole drug self-medication of household members, presence of snails in the pond, and feeding fish with green vegetation collected outside fish farms all had a significant effect on the development of FZT prevalence in the fish. CONCLUSIONS/SIGNIFICANCE: The FZT prevalence in fish increased by 11 percentage points during a one-year culture period and the risk factors for the development of infection were identified. Results also highlight that the young fish are already highly infected when stocked into the grow-out systems. This knowledge should be incorporated into control

  4. Ecological role of bluefin tuna (Thunnus thynnus) fish farms for associated wild fish assemblages in the Mediterranean Sea.

    Science.gov (United States)

    Stagličić, Nika; Šegvić-Bubić, Tanja; Ugarković, Pero; Talijančić, Igor; Žužul, Iva; Tičina, Vjekoslav; Grubišić, Leon

    2017-12-01

    The ecological effects of tuna fish farms are largely undocumented. This study confirmed their high capacity to attract surrounding wild fish. The aggregation effect persisted year round, without detectable seasonal differences. Farm impact was restricted to close proximity of the sea cages, and was more prominent over the bottom than in the water column strata. Tuna fish farms proved to be high energy trophic resources, as indicated by the enhanced fitness status of two focal species, bogue and seabream. Under abundant food supply, seabream appear to allocate the majority of energy reserves to gonad development. Farm associated bogue had greater parasite loads, with no detrimental effect on fitness status. Overall, tuna fish farms can be regarded as population sources for aggregated wild fish, and under the no fishing conditions within the leasehold areas, can serve as functional marine protected areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Concentration of radionuclides in fresh water fish downstream of Rancho Seco Nuclear Generating Plant

    International Nuclear Information System (INIS)

    Noshkin, V.E.; Eagle, R.J.; Dawson, J.M.; Brunk, J.L.; Wong, X.M.

    1984-01-01

    Fish were collected for radionuclide analysis over a 5-month period in 1984 from creeks downstream of the Rancho Seco Nuclear Generating Plant, which has been discharging quantities of some fission and activation products to the waterway since 1981. Among the fish, the bluegill was selected for intensive study because it is very territorial and the radionuclide concentrations detected should be representative of the levels in the local environment at the downstream locations sampled. Among the gamma-emitting radionuclides routinely released, only 134 Cs and 137 Cs were detected in the edible flesh of fish. Concentrations in the flesh of fish decreased with distance from the plant. The relationship between concentration and distance was determined to be exponential. Exponential equations were generated to estimate concentrations in fish at downstream locations where no site-specific information was available. Mean concentrations of 137 Cs in bluegill collected during April, May, July and August from specific downstream stations were not significantly different in spite of the release of 131 mCi to the creeks between April and August. The concentrations in fish are not responding to changes in water concentrations brought about by plant discharges. Diet appears to be a more significant factor than size or weight or water concentration in regulating body burdens of 137 Cs in these fish

  6. Values, attitudes and intention to consume wild fish versus farmed fish in Nha Trang

    OpenAIRE

    Nelka Rajani, Pemattuge

    2010-01-01

    The primary purpose of this study was to investigate the consumers’ values and the difference in consumption, attitude and intention to consume wild fish versus farmed fish in Vietnam. Second, it aimed to investigate the relationship between values, attitudes and intention to consume wild versus farmed fish by applying value-attitude-behavior model. The measurement scales used here were adapted from previous studies found in the literature. The survey was conducted in Nha Trang, Vietnam, amon...

  7. Coping styles in farmed fish: consequences for aquaculture

    OpenAIRE

    Castanheira, Maria Filipa; Conceicao, Luis E. C.; Millot, Sandie; Rey, Sonia; Begout, Marie-laure; Damsgard, Borge; Kristiansen, Tore; Hoglund, Erik; Overli, Oyvind; Martins, Catarina I. M.

    2017-01-01

    Individual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies h...

  8. Contaminants in popular farmed fish consumed in The Netherlands and their levels in fish feedContaminants in popular farmed fish consumed in The Netherlands and their levels in fish feed

    NARCIS (Netherlands)

    Leeuwen, van S.; Velzen, van M.; Swart, K.; Veen, van der I.; Traag, W.A.; Spanjer, M.; Scholten, J.; Rijn, van H.

    2008-01-01

    Investigated is a wide range of pollutants in the top five consumed fish in the Netherlands (salmon, trout, tilapia, pangasius and shrimps). Farmed fish samples were collected from different sources (supermarkets, fish stores, markets and suppliers for restaurants) and analysed for PCDD/Fs, PCBs,

  9. Levels of synthetic antioxidants (ethoxyquin, butylated hydroxytoluene and butylated hydroxyanisole) in fish feed and commercially farmed fish.

    Science.gov (United States)

    Lundebye, A-K; Hove, H; Måge, A; Bohne, V J B; Hamre, K

    2010-12-01

    Several synthetic antioxidants are authorized for use as feed additives in the European Union. Ethoxyquin (EQ) and butylated hydroxytoluene (BHT) are generally added to fish meal and fish oil, respectively, to limit lipid oxidation. The study was conducted to examine the concentrations of EQ, BHT and butylated hydroxyanisole (BHA) in several commercially important species of farmed fish, namely Atlantic salmon, halibut and cod and rainbow trout, as well as concentrations in fish feed. The highest levels of BHT, EQ and BHA were found in farmed Atlantic salmon fillets, and were 7.60, 0.17 and 0.07 mg kg(-1), respectively. The lowest concentrations of the synthetic antioxidants found were in cod. The concentration of the oxidation product ethoxyquin dimer (EQDM) was more than ten-fold higher than the concentration of parent EQ in Atlantic salmon halibut and rainbow trout, whereas this dimer was not detected in cod fillets. The theoretical consumer exposure to the synthetic antioxidants EQ, BHA and BHT from the consumption of farmed fish was calculated. The contribution of EQ from a single portion (300 g) of skinned fillets of the different species of farmed fish would contribute at most 15% of the acceptable daily intake (ADI) for a 60 kg adult. The consumption of farmed fish would not contribute measurably to the intake of BHA; however, a 300 g portion of farmed Atlantic salmon would contribute up to 75% of the ADI for BHT.

  10. FRESHWATER FISH FARMING CONDITIONS IN 1999 AND THE PRODUCTION PLAN FOR 2000

    Directory of Open Access Journals (Sweden)

    Zlatko Homen

    2000-09-01

    Full Text Available One of the activities of the Ministry of Agriculture and Forestry, Fishery and Mediterranean Agriculture Directorate, i. e. Fishery Directorate to be more specific, is the monitoring of conditions in freshwater fish farming. The objective of this work is to show conditions in freshwater fish farming during 1999. and to provide a production plan for 2000. It will also provide detailed insight into the present conditions in freshwater fish farming and into the production trends of this field. Regarding this issue, the »Questionnaire for the Monitoring of Conditions in Freshwater Fish Farming«, was sent to fish farmers aroud the country data was processed from 22 cap ponds and 13 trout ponds. Roughe estimates of conditions were conducted for 2 fish farms, since they haven’t yet returned the mandatoruy questionnaire, i. e. the necessary data. This work features data on the number of employees in fish farms, as well as their qualifications, on the actual production and distribution of farmed freshwater fish, on the areas where production was conducted and on the overall yield. Fish food, raw materials, used tools and incentive funds paid were also taken into consideration. The difficulties faced in this branch of the economy are also inicated. Compared to 1998, a slight decrease in the number of employees of freshwater fish farms has been recorded. The total number of employees in 1999 was 655, of which 555 were on carp ponds and 100 on trout ponds. Data on the qualifications of employees for 1999 show that most of them were unskilled workers, while highly skilled workers make up a minority in this work force. The total production of freshwater in 1999. amoounted to 6.185,51 tons. Of this amount 5.592,52 tons were warm-water fish specied and 592,99 tons were cold-water fish species. Compared to 1998, production decreased by 4,89 percent. Production for 2000 has been planned to increase by 22,15 percent, i. e. the production quantity is projected

  11. Is Fish Farming an Illusion for Lake Malawi Riparian Communities under Environmental Changes?

    Directory of Open Access Journals (Sweden)

    Moses Majid Limuwa

    2018-05-01

    Full Text Available Global environmental changes have negatively affected many food systems while the demand for food has continued to rise. An urgent need exists to identify other sustainable means of producing food. This is a case in Malawi, where capture fisheries and agriculture are not supplying sufficient food. Fish farming food systems by communities who rely on inland fisheries have not been evaluated. Therefore, a study was conducted in two phases: January 2016 to May 2016 and in July 2017 to evaluate if fish farming could sustainably support livelihoods of Lake Malawi riparian communities. We used mixed methods to collect and analyze data. The data collection methods included explorative surveys, household survey interviews, focus group discussion and key informant interviews. Qualitative data was analyzed using content analysis for themes. This identified themes that were quantitatively analyzed using descriptive and inferential statistics. We observed that fish farming was dominated by men and also not the main occupation for the respondents despite owning fishponds. The respondents have water and land, which are prerequisite for any farming. The study also observed fish farming production challenges related to quality fingerlings, formulated diets, and extension services. Cases of food insecurity amongst the respondents were also prevalent due to lack of food to cover the entire year. Weak synergies existed between fish farming and agriculture restricting bio-resource flow and water usage between these two food systems, meaning the outcomes of the food systems provide unsustainable diets. Furthermore, water availability, money spent on food, and cassava cropping increased fish farming participation. Whereas operating a bicycle taxi, casual labor, former fish farming, as well as application of agricultural wastes negatively affected fish farming. On the other hand, extreme weather events (increased incidences of droughts and floods attributed to inter

  12. Consumer perceptions of farmed fish

    NARCIS (Netherlands)

    Reinders, Machiel J.; Banović, Marija; Guerrero, Lluis; Krystallis, Athanasios

    2016-01-01

    Purpose: The purpose of this paper is to investigate possible cross-cultural consumer segments in the EU aquaculture market and provide direction and focus for marketing strategies for farmed fish products. Design/methodology/approach: Selected psychographic constructs (i.e. category involvement,

  13. Diversity Patterns of Benthic Macrofauna Caused by Marine Fish Farming

    Directory of Open Access Journals (Sweden)

    Arnaldo Marín

    2011-04-01

    Full Text Available This paper reviews the patterns observed in the diversity and structure of the macrofauna benthic community under the influence of fish farming. First, we explain the effects of organic enrichment on the sediment and the consequences for the inhabiting communities. We describe the diversity trends in spatial and temporal gradients affected by fish farming and compare them with those described by the Pearson and Rosenberg model. We found that in general terms, the trends of diversity and other community parameters followed the Pearson and Rosenberg model but they can vary to some extent due to sediment local characteristics or to secondary disturbances. We also show the different mechanisms by which wild fish can affect macrofauna diversity patterns under fish farming influence. In addition, we comment the importance of the macrofauna diversity in the ecosystem functions and propose some guidelines to measure functional diversity related to relevant processes at ecosystem level. We propose more research efforts in the main topics commented in this review to improve management strategies to guarantee a good status of the diversity and ecosystem functioning of sediments influenced by fish farming.

  14. Experimental investigation of fish downstream passage and turbine related fish mortality at an innovative hydro power setup

    International Nuclear Information System (INIS)

    Geiger, Franz; Cuchet, Mathilde; Rutschmann, Peter

    2016-01-01

    The fish downstream passage of small fish at the innovative TUM hydro shaft power plant concept was investigated experimentally. The behavior of 1974 inserted individuals of brown trout, grayling, barbel, minnow and bullhead of 45 mm to 220 mm body length was observed in a fully functional test setup which included a 35 kW Kaplan turbine and a horizontal screen with 20 mm bar clearance. The 24 h tests were conducted under nature like conditions whereas the laboratory environment also enabled targeted hydraulic situations and modifications of the bypass during the test series. A recapture rate of the fish of 99% and a subsequent 96 h observation period yielded detailed information about the migration behavior and instant as well as long term mortality. The results reveal the actual passage distribution of small fish between bypass and turbine and the turbine related injury and mortality rates in dependency of fish species, fish length, turbine discharge and bypass arrangement. General trends as well as species specific particularities could be deduced. The work confirms the suitability of the employed experimental approach and the ecological potential of the investigated hydro power plant concept. The behavioral barrier effect of the screen on small fish and the necessary of appropriate downstream migration corridor were proved and quantified. (authors)

  15. The Implications of Ranaviruses to European farmed and wild freshwater fish

    DEFF Research Database (Denmark)

    Jensen, Ann Britt Bang

    The present thesis explores the implications of ranaviruses to European farmed and wild freshwater fish. The work presented was carried out as a part of the EU project “Risk assessment of new and emerging systemic iridoviral diseases for European fish and aquatic ecosystems” which was initiated...... in 2005 as a reaction to the speculation that ranaviruses might pose a serious threat to both farmed and wild-living freshwater fish and amphibians within the European community. In the present thesis, the purpose is to determine the implications of ranaviruses to European freshwater farmed and wild......-living fish. The following specific objectives are addressed: Objective 1: To determine the susceptibility of selected European freshwater fish to a panel of ranaviruses Objective 2: To determine whether ornamental fish are susceptible to or can be carriers of ranaviruses Objective 3: To develop a model...

  16. Contribution of fish farming to the nutrient loading of the Mediterranean

    Directory of Open Access Journals (Sweden)

    Ioannis Karakassis

    2005-06-01

    Full Text Available Mediterranean fish farming has grown exponentially during the last 20 years. Although there is little evidence of the impact on the trophy status around fish farms, there are concerns that the release of solute wastes from aquaculture might affect larger scales in the ecosystem by changing the nutrient load. After combining information from various sources on waste production and on nutrient loads, it was concluded that the overall N and P waste from fish farms in the Mediterranean represents less than 5% of the total annual anthropogenic discharge, and the overall annual increase in P and N pools in the Mediterranean, under a production rate of 150000 tons, is less than 0.01%. The proportion of fish farming discharged nutrients was slightly higher in the eastern Mediterranean. A simple model was used to assess the long-term effects of nutrients released from various sources taking into account the water renewal rate in the Mediterranean. We conclude that, in the long term, fish farm waste could cause a 1% increase in nutrient concentrations in contrast to other anthropogenic activities which might double the Mediterranean nutrient pool.

  17. The Impact of Impoundment on Mercury Bioaccumulation in Fish Downstream from a Newly Constructed Reservoir, Wujiang River, Southwest China.

    Science.gov (United States)

    Li, Sixin; Zhou, Lianfeng; Chang, Jianbo; Yang, Zhi; Hu, Juxiang; Hongjun, Wang

    2017-11-01

    Mercury concentrations in fish were investigated downstream from a newly impounded subtropical reservoir in August 2008. After 6-7 months of reservoir impoundment, mean mercury concentration in fish from downstream is significantly increased by 1.9 times. Not only carnivorous fish but also benthic fish had significantly higher total mercury concentrations than others. No significant correlation was found between total mercury concentrations and body length or weight of 13 fish species. Compared with the pre-impoundment, total mercury in fish from downstream is significantly increased by reservoir impoundment, but the increased rate is lower than those in subarctic and temperate areas. Fish samples surpassed the Chinese hygienic standard for tolerances of mercury in foods increased by 4.3%. More attention should be given to fish mercury levels from downstream sites to prevent possible adverse effects on the health of local people.

  18. PROSPECTS OF THE KLEBAN-BYK RESERVOIR USE AS A SPECIAL COMMODITY FISH FARM

    Directory of Open Access Journals (Sweden)

    Khrystenko D.S.

    2013-09-01

    Full Text Available The current state of fish fauna was analized for the Kleban-Byk reservoir (village Konstantinovka of Donetsk region under the influence of fishery activity of a special commodity fish farms. Reservoir aboriginal fish fauna consists of species with low fishery value. The native fish fauna can not provide the high productivity of reservoir with a rational use of feed resources. However, linear and weight growth of alien fish species confirms the high trophic status of the reservoir and its potential for aquaculture under regime of special commodity fish farm. We also established the absence of negative effects of continuous fishery activities of special commodity fish farms on the life conditions of native fish fauna representatives.

  19. Environmental impacts of coastal fish farming; Carbon and Nitrogen budgets for trout farming in Kaldbacksfjord, Faroe Islands

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated......% of nitrogen derived from fish food settled on the seabed, where it was either mineralized or accumulated in the sediment. Based on transect measurements of diagenetic activity, the farm footprint was found to cover an area similar to 10 times the farm area. OC mineralization in the sediment increased linearly...

  20. Farming in a fish tank.

    Science.gov (United States)

    Youth, H

    1992-01-01

    Water, fish, and vegetables are all things that most developing countries do not have enough of. There is a method of food production called aquaculture that integrates fish and vegetable growing and conserves and purifies water at the same time. A working system that grows vegetables and fish for regional supermarkets in Massachusetts is a gravity fed system. At the top of the system is a 3,000 gallon fish rearing tank that measures 12 feet in diameter. Water trickles out of the tank and fish wastes are captured which can be composted and used in farm fields. The water goes into a bio filter that contains bacteria which convert harmful ammonia generated from fish waste into beneficial nitrate. Then the water flows into 100 foot long hydroponic tanks where lettuce grows. A 1/6 horsepower pump return the purified water to the fish tank and completes the cycle. The key to success is maintaining a balance between the fish nutrients and waste and the plants nutrients and waste. The system is estimated to produce 35,000 heads of lettuce and 2 tons of fish annually which translates into $23,500. The system could be adapted to developing countries with several modifications to reduce the start up cost.

  1. Long-chain omega-3 from low-trophic-level fish provides value to farmed seafood.

    Science.gov (United States)

    Bibus, Douglas M

    2015-03-01

    Low-trophic-level fish are a crucial source of long-chain (LC) omega-3 fatty acids for farmed fish and humans. Many farm-raised fish species have a clear need for these nutrients. Farmed fish deposit the LC omega-3s in their flesh and transfer them up the food chain. However, the content of LC omega-3s in farm-raised seafood continues to decline, while the content of shorter-chain plant-sourced omega-3s, and pro-inflammtory omega-6s continue to increase. This reduces its nutritional worth. The value of low-trophic-level fish is often viewed merely as its price at the dock. Some reports and metrics steer public attention towards the mass balance between quantities of low-trophic-level fish and farmed seafood. However, the the nutritional value of seafood is more important than its mere quantities. The role of low-trophic-level fish in human nutrition, health, and wellbeing is a fundamental component of its economic value to society.

  2. Fishing Farmers or Farming Fishers? Fishing Typology of Inland Small-Scale Fishing Households and Fisheries Management in Singkarak Lake, West Sumatra, Indonesia

    Science.gov (United States)

    Yuerlita; Perret, Sylvain Roger; Shivakoti, Ganesh P.

    2013-07-01

    Technical and socio-economic characteristics are known to determine different types of fishers and their livelihood strategies. Faced with declining fish and water resources, small-scale fisheries engage into transformations in livelihood and fishing practices. The paper is an attempt to understand these changes and their socio-economic patterns, in the case of Singkarak Lake in West Sumatra, Indonesia. Based upon the hypothesis that riparian communities have diverse, complex yet structured and dynamic livelihood systems, the paper's main objective is to study, document and model the actual diversity in livelihood, practices and performance of inland small-scale fisheries along the Singkarak Lake, to picture how households are adapted to the situation, and propose an updated, workable model (typology) of those for policy. Principal component analysis and cluster analysis were used to develop a typology of fishing households. The results show that small-scale fishers can be classified into different types characterized by distinct livelihood strategies. Three household types are identified, namely "farming fishers" households (type I, 30 %), "fishing farmers" households (type II, 30 %), and "mainly fishers" households (type III, 40 %). There are significant differences among these groups in the number of boats owned, annual fishing income, agriculture income and farming experience. Type I consists of farming fishers, well equipped, with high fishing costs and income, yet with the lowest return on fishing assets. They are also landowners with farming income, showing the lowest return on land capital. Type II includes poor fishing farmers, landowners with higher farming income; they show the highest return on land asset. They have less fishing equipment, costs and income. Type III (mainly fishers) consists of poorer, younger fishers, with highest return on fishing assets and on fishing costs. They have little land, low farming income, and diversified livelihood

  3. Performance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent.

    Science.gov (United States)

    Toledo, J J; Penha, J

    2011-02-01

    The increasing release of untreated fish farming effluents into water courses that flow to the Pantanal wetlands in Mato Grosso (Brazil) may drive this ecosystem to eutrophication. Therefore, the growth of Azolla caroliniana Willd. and Salvinia auriculata Aubl. in fish farming effluent and their effect on its quality were evaluated for 48 days in a greenhouse. The results were compared to those obtained in a nutrient rich solution (Hoagland ½ medium). Azolla caroliniana showed lower relative growth rate in fish farming effluent (0.020 d-1) than in Hoagland ½ medium (0.029 d-1). However, S. auriculata grew slightly better in fish farming effluent (0.030 d-1) than in Hoagland ½ medium (0.025 d-1). The species apparently contributed to reduce nitrate and phosphate concentration in Hoagland ½ medium. However, in fish farming effluent, only electrical conductivity and pH were reduced by plants compared to the control without plants. Thus, A. caroliniana and S. auriculata show low potential for improving effluent quality.

  4. Biogeochemical malfunctioning in sediments beneath a deep-water fish farm.

    Science.gov (United States)

    Valdemarsen, Thomas; Bannister, Raymond J; Hansen, Pia K; Holmer, Marianne; Ervik, Arne

    2012-11-01

    We investigated the environmental impact of a deep water fish farm (190 m). Despite deep water and low water currents, sediments underneath the farm were heavily enriched with organic matter, resulting in stimulated biogeochemical cycling. During the first 7 months of the production cycle benthic fluxes were stimulated >29 times for CO(2) and O(2) and >2000 times for NH(4)(+), when compared to the reference site. During the final 11 months, however, benthic fluxes decreased despite increasing sedimentation. Investigations of microbial mineralization revealed that the sediment metabolic capacity was exceeded, which resulted in inhibited microbial mineralization due to negative feed-backs from accumulation of various solutes in pore water. Conclusions are that (1) deep water sediments at 8 °C can metabolize fish farm waste corresponding to 407 and 29 mmol m(-2) d(-1) POC and TN, respectively, and (2) siting fish farms at deep water sites is not a universal solution for reducing benthic impacts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Parasitic fauna in hybrid tambacu from fish farms

    Directory of Open Access Journals (Sweden)

    Ronilson Macedo Silva

    2013-08-01

    Full Text Available The objective of this work was to evaluate the parasitic fauna of hybrid tambacu (Colossoma macropomum x Piaractus mesopotamicus from fish farms and the host-parasite relationship. A hundred and fourteen fish were collected from four fish farms in Macapá, in the state of Amapá, Brazil, 80.7% of which were infected by: Ichthyophthirius multifiliis (Ciliophora; Piscinoodinium pillulare (Dinoflagellida; Anacanthorus spatulatus, Notozothecium janauachensis, and Mymarothecium viatorum (Monogenoidea; Neoechinorhynchus buttnerae (Acanthocephala; Cucullanus colossomi (Nematoda; Perulernaea gamitanae (Lernaeidae; and Proteocephalidae larvae (Cestoda. A total of 8,136,252 parasites were collected from the examined fish. This is the first record of N. buttnerae, C. colossomi, N. janauachensis, M. viatorum, and Proteocephalidae for hybrid tambacu in Brazil. Ichthyophthirius multifiliis was the most prevalent parasite, whereas endohelminths were the less. A positive correlation was observed between number of I. multifiliis and total length and weight of fish, as well as between number of P. gamitanae and total length. The infection by I. multifiliis had association with the parasitism by Monogenoidea. Low water quality contributes to high parasitism of hybrid tambacu by ectoparasites, which, however, does not influence the relative condition factor of fish.

  6. Women in fish farming and gender perspectives | Singh | Nigerian ...

    African Journals Online (AJOL)

    In fish farming, women are actively involved in production and other important activities like catching, cleaning, processing, peeling, drying, fish marketing etc. ... making feed-mix, cleaning ponds and guarding the ponds during day time.

  7. Sources and fate of antimicrobials in integrated fish-pig and non-integrated tilapia farms.

    Science.gov (United States)

    Li, Kang; Liu, Liping; Zhan, Jia; Scippo, Marie-Louise; Hvidtfeldt, Kristian; Liu, Yuan; Dalsgaard, Anders

    2017-10-01

    Antimicrobial contamination in aquaculture products constitutes a food safety hazard, but little is known about the introduction and accumulation of antimicrobials in integrated fish-pig aquaculture. This study, conducted in 2013, aimed to determine the residues of 11 types of antimicrobials by UPLC-MS/MS analysis in fish feed (n=37), pig feed (n=9), pig manure (n=9), pond sediment (n=20), fish skin (n=20) and muscle tissue (n=20) sampled from integrated tilapia-pig farms, non-integrated tilapia farms and fish feed supply shops. There was a higher occurrence of antimicrobial residues in fish skin from both integrated and non-integrated farms, and in pig manure. Enrofloxacin (3.9-129.3μg/kg) and sulfadiazine (0.7-7.8μg/kg) were commonly detected in fish skin and muscle, pig manure and pond sediment from integrated farms, with different types of antimicrobials found in pig manure and tilapia samples. In non-integrated farms, sulfadiazine (2.5-89.9μg/kg) was the predominant antimicrobial detected in fish skin and muscle, fish feed and pond sediment. In general, antimicrobials seemed not to be commonly transmitted from pig to fish in tilapia-pig integrated farms, and fish feed, pig feed and pond sediment did not seem as important sources of the antimicrobials found in fish from both systems. The frequent findings of antimicrobial residues in fish skin compared with fish muscle was probably due to different pharmacokinetics in different tissue types, which have practical food safety implications since antimicrobial residues monitoring is usually performed analyzing mixed skin and fish muscle samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Hydroacoustic registration of fish abundance of offshore wind farms. Horns Rev offshore wind farm. Annual report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Hvidt, C.B.; Bruenner, L.; Reier Knudsen, F.

    2005-05-15

    Elsam Engineering AS has approved the implementation of a project concerning the registration of fish communities in Horns Rev Offshore Wind Farm with use of hydroacoustic methods. In a joint effort, Bio/consult as, Carl Bro as and SIMRAD AS have monitored the fish communities at Horns Rev Offshore Wind Farm using a new hydroacoustic methodology. The new hydroacoustic technique combines the use of scientific sonar acoustics with GPS to determine the density, diversity and location of fish. The objectives of this project were to test the possibility of using hydroacoustic techniques as alternative methods to traditional techniques to assess the fish assemblage inhabiting offshore wind farms and to investigate the possible effect from the wind farm and hard bottom substrates (turbine foundations) on fish abundance. The field study was carried out October 9-10, 2004 and consisted of four horizontal hydroacoustic survey transects each covering impact and reference areas. Transects were surveyed in order to achieve identical impact and reference transect pairs concerning environment, topography and time correspondence. The hydroacoustic equipment consisted of a SIMRAD EK60/EY60 echo sounder with a split-beam transducer (Simrad ES 120-4x10) mounted on a pan and tilt unit, a transceiver, a laptop extended with a GPS-receiver and additional large external hard discs. The raw data files from EK60 were converted to echogram files suitable for the post processing application, Sonar5-Pro. The Sonar5-Pro software makes it possible to filter out echo detections from the surface and the bottom, as well as perform cross filter detection. The validity of the results using the hydroacoustic method is high due to the cross filtering and single target tracking technique. From the hydroacoustic results, no or very little effect from the wind farm or from hard bottom substrates was found on the fish densities at Horns Rev Wind Farm at the time of the survey. The execution of the field

  9. Performance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent

    Directory of Open Access Journals (Sweden)

    JJ. Toledo

    Full Text Available The increasing release of untreated fish farming effluents into water courses that flow to the Pantanal wetlands in Mato Grosso (Brazil may drive this ecosystem to eutrophication. Therefore, the growth of Azolla caroliniana Willd. and Salvinia auriculata Aubl. in fish farming effluent and their effect on its quality were evaluated for 48 days in a greenhouse. The results were compared to those obtained in a nutrient rich solution (Hoagland ½ medium. Azolla caroliniana showed lower relative growth rate in fish farming effluent (0.020 d-1 than in Hoagland ½ medium (0.029 d-1. However, S. auriculata grew slightly better in fish farming effluent (0.030 d-1 than in Hoagland ½ medium (0.025 d-1. The species apparently contributed to reduce nitrate and phosphate concentration in Hoagland ½ medium. However, in fish farming effluent, only electrical conductivity and pH were reduced by plants compared to the control without plants. Thus, A. caroliniana and S. auriculata show low potential for improving effluent quality.

  10. Environmental impact assessment of fish farm hatcheries ...

    African Journals Online (AJOL)

    Environmental impact assessment of fish farm hatcheries management in lower ... Environmental impact assessments were taken to determine the causes of ... Of significance of impact assessment were activities like air, traffic, noise, had ...

  11. Semi-continuously addition of peracetic acid to a flow-through fish farm

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Henriksen, Niels Henrik

    2017-01-01

    •Demonstration of a safe and reliable practical method to reduce ectoparasites related mortality of farmed fish.•Central peracetic acid application caused even distribution to all ponds and considered suitable for organic fish farming.•Low dose and easy degradable peracetic acid is an alternative...

  12. A Global Analysis of the Relationship between Farmed Seaweed Production and Herbivorous Fish Catch.

    Directory of Open Access Journals (Sweden)

    E James Hehre

    Full Text Available Globally, farmed seaweed production is expanding rapidly in shallow marine habitats. While seaweed farming provides vital income to millions of artisanal farmers, it can negatively impact shallow coral reef and seagrass habitats. However, seaweed farming may also potentially provide food subsidies for herbivorous reef fish such as the Siganidae, a valuable target family, resulting in increased catch. Comparisons of reef fish landings across the central Philippines revealed that the catch of siganids was positively correlated to farmed seaweed production whilst negatively correlated to total reef fish catch over the same period of time. We tested the generality of this pattern by analysing seaweed production, siganid catch, and reef fish catch for six major seaweed-producing countries in the tropics. We hypothesized that increased seaweed production would correspond with increased catch of siganids but not other reef fish species. Analysis of the global data showed a positive correlation between farmed seaweeds and siganids in Southeast Asia (Indonesia, Malaysia, and the Philippines but not Africa (Tanzania and Zanzibar, or the Western Pacific (Fiji. In Southeast Asia, siganid catch increased disproportionately faster with seaweed production than did reef fish catch. Low continuity, sporadic production and smaller volumes of seaweed farming may explain the differences.

  13. A Global Analysis of the Relationship between Farmed Seaweed Production and Herbivorous Fish Catch.

    Science.gov (United States)

    Hehre, E James; Meeuwig, Jessica J

    2016-01-01

    Globally, farmed seaweed production is expanding rapidly in shallow marine habitats. While seaweed farming provides vital income to millions of artisanal farmers, it can negatively impact shallow coral reef and seagrass habitats. However, seaweed farming may also potentially provide food subsidies for herbivorous reef fish such as the Siganidae, a valuable target family, resulting in increased catch. Comparisons of reef fish landings across the central Philippines revealed that the catch of siganids was positively correlated to farmed seaweed production whilst negatively correlated to total reef fish catch over the same period of time. We tested the generality of this pattern by analysing seaweed production, siganid catch, and reef fish catch for six major seaweed-producing countries in the tropics. We hypothesized that increased seaweed production would correspond with increased catch of siganids but not other reef fish species. Analysis of the global data showed a positive correlation between farmed seaweeds and siganids in Southeast Asia (Indonesia, Malaysia, and the Philippines) but not Africa (Tanzania and Zanzibar), or the Western Pacific (Fiji). In Southeast Asia, siganid catch increased disproportionately faster with seaweed production than did reef fish catch. Low continuity, sporadic production and smaller volumes of seaweed farming may explain the differences.

  14. Downstream passage of fish larvae and eggs through a small-sized reservoir, Mucuri river, Brazil

    Directory of Open Access Journals (Sweden)

    Paulo S. Pompeu

    2011-12-01

    Full Text Available In South America, one important symptom of the failure of fish passages to sustain fish migratory recruitment is the inability of eggs and larvae to reach the nurseries. This is especially so when the breeding areas are located upstream of a reservoir, and the floodplain is downstream of the dam. Therefore, the transport of fish larvae and eggs across reservoir barriers is a key factor in the development of effective conservation strategies. In this paper, we evaluate the potential for migratory fish larvae and egg transportation across a small size reservoir in eastern Brazil. We sampled fish daily between 15th October 2002 and 15th February 2003 (spawning period in the Mucuri River, immediately upstream of the reservoir and downstream of the Santa Clara Power Plant dam. Our study was the first to indicate the possibility of successful larval passage through the reservoir of a hydroelectric reservoir and dam in South America, and showed that the passage of migratory fish larvae was associated significantly with residence time of water in the reservoir. The relatively short water residence time and elevated turbidity of the Santa Clara's reservoir waters during the rainy season certainly contributed to the successful passage, and can be considered as key factors for a priori evaluations of the feasibility of a downstream larval passage.

  15. Numerical modelling of organic waste dispersion from fjord located fish farms

    Science.gov (United States)

    Ali, Alfatih; Thiem, Øyvind; Berntsen, Jarle

    2011-07-01

    In this study, a three-dimensional particle tracking model coupled to a terrain following ocean model is used to investigate the dispersion and the deposition of fish farm particulate matter (uneaten food and fish faeces) on the seabed due to tidal currents. The particle tracking model uses the computed local flow field for advection of the particles and random movement to simulate the turbulent diffusion. Each particle is given a settling velocity which may be drawn from a probability distribution according to settling velocity measurements of faecal and feed pellets. The results show that the maximum concentration of organic waste for fast sinking particles is found under the fish cage and continue monotonically decreasing away from the cage area. The maximum can split into two maximum peaks located at both sides of the centre of the fish cage area in the current direction. This process depends on the sinking time (time needed for a particle to settle at the bottom), the tidal velocity and the fish cage size. If the sinking time is close to a multiple of the tidal period, the maximum concentration point will be under the fish cage irrespective of the tide strength. This is due to the nature of the tidal current first propagating the particles away and then bringing them back when the tide reverses. Increasing the cage size increases the likelihood for a maximum waste accumulation beneath the fish farm, and larger farms usually means larger biomasses which can make the local pollution even more severe. The model is validated by using an analytical model which uses an exact harmonic representation of the tidal current, and the results show an excellent agreement. This study shows that the coupled ocean and particle model can be used in more realistic applications to help estimating the local environmental impact due to fish farms.

  16. THE NEED FOR DIVERSIFICATION IN FISH FARMING PRODUCTION

    Directory of Open Access Journals (Sweden)

    Krešimir Pažur

    1999-06-01

    Full Text Available One of the characteristics of developed economies in the world is a very rich and diversified offer of goods. There are many products of different assortment, of different quality and price on the market. In keeping with the marketing conception, the production is trying to satisfy all potential consumers. Croatian freshwater fish farming has not yet reached this stage. The assortment is very limited and includes mostly carp (up to 80%, Californian trout (up to 10%, grass carp (around 4%, wels, pike-perch and pike together up to 2.70%, while the rest are commercially insignificant and uninteresting fish species. In the last few years, an increasingly important type of consumers has emerged on the market sporting anglers whose importance is growing and bringing totally new, specific demands that the fish ponds at the moment cannot meet, except maybe in marginal quantities. There is a categorical imperative of a fast adjustment of the production assortment of our fishing farms to the tendencies in the nourishment of the population in developed countries that can also be observed in our country and to the demands and needs of sporting anglers.

  17. Economics of fish farming in Ibadan Metropolis | Yusuf | Nigerian ...

    African Journals Online (AJOL)

    The study assesses the economics of fish farming in Ibadan Metropolis. The data for the study were collected from 50 fish farmers with the aid of structured questionnaires. The data were analyses using descriptive, gross margin and regression techniques. The study revealed that most farmers had secondary education and ...

  18. Farmed fish welfare-suffering assessment and impact on product quality

    Directory of Open Access Journals (Sweden)

    Bianca Maria Poli

    2010-01-01

    Full Text Available Fish welfare, suffering and the perception of pain were debated, together with several factors reducing infra vitam welfare of farmed fish (genetic, environment, density, malnutrition, starvation, cataracts, deformities, vaccination side effects, transport, handling, confinement, crowding, harvesting, killing method. Behavioural and physiological stress responses were considered as indicators of welfare reduction. The effects of pre-slaughter management practices, and the most commonly used stunning/slaughtering methods on welfare and quality reduction of farmed fish were discussed. A number of indicators can be used to assess fish welfare-suffering, both in a scientific and practical context, such as behavioural, haematic, cellular, tissue post mortem fish stress and quality indicators, but none of them are optimal. The best strategy for a reliable assessment of fish welfare/suffering and their impact on product quality is a multidisciplinary approach that takes into account animal behaviour and the different biochemical and physiological ante mortem and post mortem processes involved: several components, all influenced in a similar way by the same condition, suggest real welfare and quality reduction.

  19. Spatio-temporal variability of ichthyophagous bird assemblage around western Mediterranean open-sea cage fish farms.

    Science.gov (United States)

    Aguado-Giménez, Felipe; Eguía-Martínez, Sergio; Cerezo-Valverde, Jesús; García-García, Benjamín

    2018-06-14

    Ichthyophagous birds aggregate at cage fish farms attracted by caged and associated wild fish. Spatio-temporal variability of such birds was studied for a year through seasonal visual counts at eight farms in the western Mediterranean. Correlation with farm and location descriptors was assessed. Considerable spatio-temporal variability in fish-eating bird density and assemblage structure was observed among farms and seasons. Bird density increased from autumn to winter, with the great cormorant being the most abundant species, also accounting largely for differences among farms. Grey heron and little egret were also numerous at certain farms during the coldest seasons. Cattle egret was only observed at one farm. No shags were observed during winter. During spring and summer, bird density decreased markedly and only shags and little egrets were observed at only a few farms. Season and distance from farms to bird breeding/wintering grounds helped to explain some of the spatio-temporal variability. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Fish production and some traits of meat quality in rainbow trout (Oncorhynchus mykiss farmed in different production systems

    Directory of Open Access Journals (Sweden)

    St. Stoyanova

    2016-12-01

    Full Text Available Abstract. The rainbow trout (Oncorhynchus mykiss, an important species in Bulgarian aquaculture, is farmed in different production systems as raceways, net cages etc. The aim of the present study was to evaluate the effect of two different rearing systems on fish production, survival rate, meat chemical, mineral composition and farming economic efficiency of culticated rainbow trout (Oncorhynchus mykiss. The information from a survey on fish production and economic efficiency traits was collected from two national rainbow trout farms using the two commonest fish farming systems: in raceways, Happy Fish Ltd fish farm and in net cages, Forest Group Ltd fish farm. The average individual weight gain (g, total weight gain (kg, feed conversion ratio, production costs of 1 kg fish and the economic efficiency coefficients were determined for the two studied fish farms. The final live weight of rainbow trout in net cages was 0.30 kg vs 0.35 kg in raceways. The average individual weight gain was higher in raceways farming system (0.30 kg than in net cages farm (0.26 kg. The mortality rate of fish in raceways was considerably lower: only 1% as compared to that in net cages (4%. The feed conversion ratio at the end of the experiment showed identical values for trout in both farms 1.01. The meat water content of fish reared in raceways and net cages was 77.46±0.65% and 74.52±0.52% respectively (P≤0.01.The protein content of fish meat was higher in fish farmed in net cages 18.84±0.29% as compared to fish cultivated in raceways 17.60±0.49% (P 0.05. Meat fat content of rainbow trout, reared in the net cage system was also considerably higher (5.26±0.30% than the respective parameter in fish farmed in ponds (3.60±0.15% (P≤0.001. The content of Ca and P was higher in rainbow trouts reared in raceways (138.96±1.12 mg.kg and 2844.32±39.31 mg.kg 1 -1 -1 compared with the values of these parameters of fish in net cages (134.46±1.96 mg.kg and 2690.31±42

  1. Status and prospects of fish farming in Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Verlecar, X.N.

    -cum-prawn culture. Relevant information on the indigenous methods of cultivating common species, their annual yield and economics of aquaculture are discussed in the paper with reference to future prospects of fish farming in Goa...

  2. Logistic Regression Analysis on Factors Affecting Adoption of Rice-Fish Farming in North Iran

    Directory of Open Access Journals (Sweden)

    Seyyed Ali NOORHOSSEINI-NIYAKI

    2012-06-01

    Full Text Available We evaluated the factors influencing the adoption of rice-fish farming in the Tavalesh region near the Caspian Sea in northern Iran. We conducted a survey with open-ended questions. Data were collected from 184 respondents (61 adopters and 123 non-adopters randomly sampled from selected villages and analyzed using logistic regression and multi-response analysis. Family size, number of contacts with an extension agent, participation in extension-education activities, membership in social institutions and the presence of farm workers were the most important socio-economic factors for the adoption of rice-fish farming system. In addition, economic problems were the most common issue reported by adopters. Other issues such as lack of access to appropriate fish food, losses of fish, lack of access to high quality fish fingerlings and dehydration and poor water quality were also important to a number of farmers.

  3. Downstream impacts of dams: shifts in benthic invertivorous fish assemblages

    Science.gov (United States)

    Granzotti, Rafaela Vendrametto; Miranda, Leandro E.; Agostinho, Angelo A.; Gomes, Luiz Carlos

    2018-01-01

    Impoundments alter connectivity, sediment transport and water discharge in rivers and floodplains, affecting recruitment, habitat and resource availability for fish including benthic invertivorous fish, which represent an important link between primary producers and higher trophic levels in tropical aquatic ecosystems. We investigated long-term changes to water regime, water quality, and invertivorous fish assemblages pre and post impoundment in three rivers downstream of Porto Primavera Reservoir in south Brazil: Paraná, Baía and Ivinhema rivers. Impacts were distinct in the Paraná River, which is fully obstructed by the dam, less evident in the Baía River which is partially obstructed by the dam, but absent in the unimpounded Ivinhema River. Changes in water regime were reflected mainly as changes in water-level fluctuation with little effect on timing. Water transparency increased in the Paraná River post impoundment but did not change in the Baía and Ivinhema rivers. Changes in fish assemblages included a decrease in benthic invertivorous fish in the Paraná River and a shift in invertivorous fish assemblage structure in the Baía and Paraná rivers but not in the unimpounded Ivinhema River. Changes in water regime and water transparency, caused by impoundment, directly or indirectly impacted invertivorous fish assemblages. Alterations of fish assemblages following environmental changes have consequences over the entire ecosystem, including a potential decrease in the diversity of mechanisms for energy flow. We suggest that keeping existing unimpounded tributaries free of dams, engineering artificial floods, and intensive management of fish habitat within the floodplain may preserve native fish assemblages and help maintain functionality and ecosystem services in highly impounded rivers.

  4. A meta-analysis approach to the effects of fish farming on soft bottom polychaeta assemblages in temperate regions

    International Nuclear Information System (INIS)

    Martinez-Garcia, Elena; Sanchez-Jerez, Pablo; Aguado-Giménez, Felipe; Ávila, Pablo; Guerrero, Alejandro; Sánchez-Lizaso, Jose Luis; Fernandez-Gonzalez, Victoria; González, Nieves; Gairin, Joan Ignasi; Carballeira, Carlos; García-García, Benjamín; Carreras, Jordi

    2013-01-01

    Highlights: ► This study was carried out in ten fish farms along the Spanish coast. ► Fish farm caused a decline in abundance and family richness in polychaete assemblages. ► There are two main groups of polychaeta, sensitive families and tolerant families. ► The main influence is associated to percentage of silt and clays. ► Total free sulfides, silt and clays and 15 N, have influence on polychaete populations. -- Abstract: Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques. Abundance, richness and diversity showed significant decreases under fish farm conditions. Distribution patterns of polychaetes responded to combinations of physicochemical variables. The main ones are sulfide concentration, silt and clays percentage, and stable nitrogen isotope ratio. The results showed that some families are tolerant, Capitellidae, Dorvilleidae, Glyceridae, Nereididae, Oweniidae and Spionidae; while others are sensitive to fish farm pollution, Magelonidae, Maldanidae, Nephtyidae, Onuphidae, Paralacydoniidae, Paraonide, Sabellidae and also Cirratulidae in spite of being reported as a tolerant family

  5. 76 FR 54072 - Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program, Livestock Indemnity...

    Science.gov (United States)

    2011-08-31

    ... for Livestock, Honeybees, and Farm-Raised Fish Program, Livestock Indemnity Program, and General... clarifying amendments and corrections to the regulations for the Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program (ELAP) and the Livestock Indemnity Program (LIP) to clarify when...

  6. Reservoir stratification affects methylmercury levels in river water, plankton, and fish downstream from Balbina hydroelectric dam, Amazonas, Brazil.

    Science.gov (United States)

    Kasper, Daniele; Forsberg, Bruce R; Amaral, João H F; Leitão, Rafael P; Py-Daniel, Sarah S; Bastos, Wanderley R; Malm, Olaf

    2014-01-21

    The river downstream from a dam can be more contaminated by mercury than the reservoir itself. However, it is not clear how far the contamination occurs downstream. We investigated the seasonal variation of methylmercury levels in the Balbina reservoir and how they correlated with the levels encountered downstream from the dam. Water, plankton, and fishes were collected upstream and at sites between 0.5 and 250 km downstream from the dam during four expeditions in 2011 and 2012. Variations in thermal stratification of the reservoir influenced the methylmercury levels in the reservoir and in the river downstream. Uniform depth distributions of methylmercury and oxygen encountered in the poorly stratified reservoir during the rainy season collections coincided with uniformly low methylmercury levels along the river downstream from the dam. During dry season collections, the reservoir was strongly stratified, and anoxic hypolimnion water with high methylmercury levels was exported downstream. Methylmercury levels declined gradually to 200 km downstream. In general, the methylmercury levels in plankton and fishes downstream from the dam were higher than those upstream. Higher methylmercury levels observed 200-250 km downstream from the dam during flooding season campaigns may reflect the greater inflow from tributaries and flooding of natural wetlands that occurred at this time.

  7. Improved intake design for downstream migrating fish at hydropower plants

    International Nuclear Information System (INIS)

    Mih, W.C.

    1991-01-01

    This paper reports on hydroelectric power projects on the Columbia River which provided low-cost electricity to the Pacific Northwest. However, they are detrimental to anadromous fisheries resources. Anadromous fish are migratory. They begin their life in shallow mountain streams. After several months, they migrate to the ocean, where the fish grow to maturity before their return migration. Remarkably, most anadromous fish return to spawn in their natal streams. At dams, the upstream migration of grown salmon and steelhead is accomplished through fishways. The downstream migration of juveniles remains a serious problem. Juvenile fish follow the water flow during their sea-ward migration. When passing through a turbine, fish can be severely injured due to the sudden pressure drop, high velocity shear zones, and rotating turbine blades. Stunned fish that survive the gauntlet of the turbine are easy prey for sea gulls and squawfish in the tailrace of the powerhouse. Fish mortality per turbine passage is estimated at 15 percent. With nine hydropower projected on the main steam of the Columbia River, their combined mortality is very serious. The historical Columbia River anadromous run of about 12 million fish has declined to 2.5 million in recent years. Modern high-output hydraulic turbines are designed to be placed at a lower elevation to minimize cavitation damage to turbine blades. The modern design trend of deep intake submergence has caused parallel and unsteady vortex flow patterns in the forebay, resulting in a decrease in the guiding efficiency of the screens, such as at Bonneville Second Powerhouse and at Rocky Reach Project

  8. Factors affecting farmers' adoption of integrated rice-fish farming systems in the Mekong delta, Vietnam

    NARCIS (Netherlands)

    Bosma, R.H.; Nhan, D.K.; Udo, H.M.J.; Kaymak, U.

    2012-01-01

    This study investigated the determinants of the adoption of improved rice–fish farming systems in the Mekong delta to support policy making, agricultural land-use planning and extension of integrated rice–fish farming. Recently these systems have been referred to as adaptations to climate change,

  9. Biological assessment of aquaculture effects on effluent-receiving streams in Ghana using structural and functional composition of fish and macroinvertebrate assemblages.

    Science.gov (United States)

    Ansah, Yaw Boamah; Frimpong, Emmanuel A; Amisah, Stephen

    2012-07-01

    Biological assessment of aquatic ecosystems is widely employed as an alternative or complement to chemical and toxicity testing due to numerous advantages of using biota to determine ecosystem condition. These advantages, especially to developing countries, include the relatively low cost and technical requirements. This study was conducted to determine the biological impacts of aquaculture operations on effluent-receiving streams in the Ashanti Region of Ghana. We collected water, fish and benthic macroinvertebrate samples from 12 aquaculture effluent-receiving streams upstream and downstream of fish farms and 12 reference streams between May and August of 2009, and then calculated structural and functional metrics for biotic assemblages. Fish species with non-guarding mode of reproduction were more abundant in reference streams than downstream (P = 0.0214) and upstream (P = 0.0251), and sand-detritus spawning fish were less predominant in reference stream than upstream (P = 0.0222) and marginally less in downstream locations (P = 0.0539). A possible subsidy-stress response of macroinvertebrate family richness and abundance was also observed, with nutrient (nitrogen) augmentation from aquaculture and other farming activities likely. Generally, there were no, or only marginal differences among locations downstream and upstream of fish farms and in reference streams in terms of several other biotic metrics considered. Therefore, the scale of impact in the future will depend not only on the management of nutrient augmentation from pond effluents, but also on the consideration of nutrient discharges from other industries like fruit and vegetable farming within the study area.

  10. Health Categorisation of Fish Farms in Europe In 2011

    DEFF Research Database (Denmark)

    Olesen, Niels Jørgen; Nicolajsen, Nicole

    2012-01-01

    The Questionnaire on Surveillance and Diagnosis (S&D) included questions on how fish farms are health categorised according to Council Directive 2006/88/EC in the respective countries. More than half of the authorised farms in Europe are in category III for VHS and IHN and the remaining in category...... I or II. According to these official data almost no farms are infected with either of these diseases. This might be more due to a significant underreporting than of the de facto situation. For KHV most carp farms are in category III, unknown status. Many farms in Europe are not categorised yet......, and unfortunately the situation have not improved much from 2010.. In the questionnaire we ask for the number of APBs in these areas. There are several different views on how categorisation shall be performed, e.g. should VHS free marine rainbow trout farms be placed in Category III or I? If Isavirus HPR0 is found...

  11. Seasonality of reproduction and production in farm fishes, birds and mammals.

    Science.gov (United States)

    Chemineau, P; Malpaux, B; Brillard, J P; Fostier, A

    2007-03-01

    A very large majority of farm animals express seasonal variations in their production traits, thus inducing seasonal availability of fresh derived animal products (meat, milk, cheese and eggs). This pattern is in part the consequence of the farmer's objective to market his products in the most economically favourable period. It may also be imposed by the season-dependent access to feed resources, as in ruminants, or by the specific requirements derived from adaptation to environmental conditions such as water temperature in fish. But seasonal variations in animal products are also the consequence of constraints resulting from the occurrence of a more or less marked seasonal reproductive season in most farm animal species including fish, poultry and mammals. Like their wild counterparts, at mid and high latitudes, most farm animals normally give birth at the end of winter-early spring, the most favourable period for the progeny to survive and thus promote the next generation. As a consequence, most species show seasonal variations in their ovulation frequency (mammals and fish: presence or absence of ovulation; birds: variations or suppression of laying rates), spermatogenic activity (from moderate to complete absence of sperm production), gamete quality (variations in fertilisation rates and embryo survival), and also sexual behaviour. Among species of interest for animal production, fishes and birds are generally considered as more directly sensitive to external factors (mainly temperature in fish, photoperiod in birds). In all species, it is therefore advisable that artificial photoperiodic treatments consisting of extra-light during natural short days (in chickens, turkeys, guinea fowl, sheep and goats) or melatonin during long days (in goats, sheep) be extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres (mammals) and breeder flock

  12. A computational fluid dynamics modeling study of guide walls for downstream fish passage

    Science.gov (United States)

    Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

    2017-01-01

    A partial-depth, impermeable guidance structure (or guide wall) for downstream fish passage is typically constructed as a series of panels attached to a floating boom and anchored across a water body (e.g. river channel, reservoir, or power canal). The downstream terminus of the wall is generally located nearby to a fish bypass structure. If guidance is successful, the fish will avoid entrainment in a dangerous intake structure (i.e. turbine intakes) while passing from the headpond to the tailwater of a hydroelectric facility through a safer passage route (i.e. the bypass). The goal of this study is to determine the combination of guide wall design parameters that will most likely increase the chance of surface-oriented fish being successfully guided to the bypass. To evaluate the flow field immediately upstream of a guide wall, a parameterized computational fluid dynamics model of an idealized power canal was constructed in © ANSYS Fluent v 14.5 (ANSYS Inc., 2012). The design parameters investigated were the angle and depth of the guide wall and the average approach velocity in the power canal. Results call attention to the importance of the downward to sweeping flow ratio and demonstrate how a change in guide wall depth and angle can affect this important hydraulic cue to out-migrating fish. The key findings indicate that a guide wall set at a small angle (15° is the minimum in this study) and deep enough such that sweeping flow dominant conditions prevail within the expected vertical distribution of fish approaching the structure will produce hydraulic conditions that are more likely to result in effective passage.

  13. Impacts of fish farm pollution on ecosystem structure and function of tropical headwater streams

    International Nuclear Information System (INIS)

    Rosa, Rodrigo dos Santos; Aguiar, Anna Carolina Fornero; Boëchat, Iola Gonçalves; Gücker, Björn

    2013-01-01

    We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics. -- Highlights: ► Fish farm effluent discharge had moderate effects on stream water quality. ► Impacts on the benthic invertebrate community occurred at one stream. ► Whole-stream nitrate uptake showed no consistent impact pattern. ► Effluents caused considerable increases in stream ecosystem metabolism. ► Compliance with best management practices is important for small fish farms. -- Moderate water pollution by small fish farms caused considerable eutrophication responses in tropical headwater streams

  14. Association of health involvement and attitudes towards eating fish on farmed and wild fish consumption in Belgium, Norway and Spain

    NARCIS (Netherlands)

    Altintzoglou, T.; Vanhonacker, F.; Verbeke, W.; Luten, J.B.

    2011-01-01

    Consumers in many European countries do not equally meet the recommended daily intake levels for fish consumption. Various factors that can influence fish consumption behaviour have been identified but limited research has been performed on fish consumption behaviour, discriminating between farmed

  15. Fish farming as an innovative strategy for promoting food security in drought risk regions of Zimbabwe

    Directory of Open Access Journals (Sweden)

    Elvin Shava

    2017-11-01

    Full Text Available This article examines the implementation of fish farming as an innovative and economic strategy for promoting food security and dietary diversities among vulnerable households in drought risk areas of Zimbabwe. The declining climatic conditions and lack of economic opportunities in Mwenezi district of Zimbabwe attracted the attention of three nongovernmental organisations (NGOs to implement fish farming as an innovative mechanism to stimulate food security and generate employment in the district. The article used a qualitative research approach that includes semi-structured interviews and secondary data. The purposive sampling technique was adopted to interview participants in Mwenezi district who were involved in fish farming to assess and explore the experiences and benefits they derive from such development projects. Results for the article revealed that fish farming was well embraced by local communities as it led to improvements in food security, household income and employment regeneration. The local government including traditional leadership (Chiefs and Headmen’s supported the NGO activities as they benefited local communities. The article concludes that although fish farming was instrumental in regenerating employment, some participants still fail to participate because of laziness and desire to maintain dependency syndrome. The article recommends the NGOs to launch awareness campaigns in rural communities and increase networking with the donor community which is fundamental in attracting sustainable funding. The government can also promote fish farming in vulnerable rural communities by providing funding and capacity building programmes.

  16. Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

    Science.gov (United States)

    Fernandez-Jover, Damian; Martinez-Rubio, Laura; Sanchez-Jerez, Pablo; Bayle-Sempere, Just T.; Lopez Jimenez, Jose Angel; Martínez Lopez, Francisco Javier; Bjørn, Pål-Arne; Uglem, Ingebrigt; Dempster, Tim

    2011-03-01

    Aquaculture of carnivorous fish species in sea-cages typically uses artificial feeds, with a proportion of these feeds lost to the surrounding environment. This lost resource may provide a trophic subsidy to wild fish in the vicinity of fish farms, yet the physiological consequences of the consumption of waste feed by wild fish remain unclear. In two regions in Norway with intensive aquaculture, we tested whether wild saithe ( Pollachius virens) and Atlantic cod ( Gadus morhua) associated with fish farms (F assoc), where waste feed is readily available, had modified diets, condition and fatty acid (FA) compositions in their muscle and liver tissues compared to fish unassociated (UA) with farms. Stomach content analyses revealed that both cod and saithe consumed waste feed in the vicinity of farms (6-96% of their diet was composed of food pellets). This translated into elevated body and liver condition compared to fish caught distant from farms for cod at both locations and elevated body condition for saithe at one of the locations. As a consequence of a modified diet, we detected significantly increased concentrations of terrestrial-derived fatty acids (FAs) such as linoleic (18:2ω6) and oleic (18:1ω9) acids and decreased concentrations of DHA (22:6ω3) in the muscle and/or liver of F assoc cod and saithe when compared with UA fish. In addition, the ω3:ω6 ratio clearly differed between F assoc and UA fish. Linear discriminant analysis (LDA) correctly classified 97% of fish into F assoc or UA origin for both cod and saithe based on the FA composition of liver tissues, and 89% of cod and 86% of saithe into F assoc or UA origin based on the FA composition of muscle. Thus, LDA appears a useful tool for detecting the influence of fish farms on the FA composition of wild fish. Ready availability of waste feed with high protein and fat content provides a clear trophic subsidy to wild fish in coastal waters, yet whether the accompanying side-effect of altered fatty

  17. Sources and fate of antimicrobials in integrated fish-pig and non-integrated tilapia farms

    DEFF Research Database (Denmark)

    Li, Kang; Liu, Liping; Zhan, Jia

    2017-01-01

    residues in fish skin from both integrated and non-integrated farms, and in pig manure. Enrofloxacin (3.9–129.3 μg/kg) and sulfadiazine (0.7–7.8 μg/kg) were commonly detected in fish skin and muscle, pig manure and pond sediment from integrated farms, with different types of antimicrobials found in pig...

  18. Effects of fish farm waste on Posidonia oceanica meadows: Synthesis and provision of monitoring and management tools

    Energy Technology Data Exchange (ETDEWEB)

    Holmer, Marianne [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)], E-mail: holmer@biology.sdu.dk; Argyrou, Marina [Marine Environment Division, Department of Fisheries and Marine Research, Ministry of Agriculture, Natural Resources and Environment, 101 Bethleem Street, 1416 Nicosia (Cyprus); Dalsgaard, Tage [Department of Marine Ecology, National Environmental Research Institute, Aarhus University, Vejlsovej 25, P.O. Box 314, DK-8600 Silkeborg (Denmark); Danovaro, Roberto [Department of Marine Science, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona (Italy); Diaz-Almela, Elena; Duarte, Carlos M. [IMEDEA (CSIC-UIB), Miquel Marques 21, 07190 Esporles (Illes Balears) (Spain); Frederiksen, Morten [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Grau, Antoni [Direccio General de Pesca, Conselleria d' Agricultura i Pesca, Govern de les Illes Balears, Foners 10, 07006 Palma de Mallorca (Illes Balears) (Spain); Karakassis, Ioannis [Marine Ecology Laboratory, Biology Department, University of Crete, Heraklion, 71409 Crete (Greece); Marba, Nuria [IMEDEA (CSIC-UIB), Miquel Marques 21, 07190 Esporles (Illes Balears) (Spain); Mirto, Simone [Institute for the Marine Coastal Environment, National Council of Research, Spianata S. Raineri, 86, 98122 Messina (Italy); Perez, Marta [Departament d' Ecologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona (Spain); Pusceddu, Antonio [Department of Marine Science, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona (Italy); Tsapakis, Manolis [Institute of Oceanography, Hellenic Center for Marine Research, P.O. Box 2214, GR 71003 Heraklion, Crete (Greece)

    2008-09-15

    This paper provides a synthesis of the EU project MedVeg addressing the fate of nutrients released from fish farming in the Mediterranean with particular focus on the endemic seagrass Posidonia oceanica habitat. The objectives were to identify the main drivers of seagrass decline linked to fish farming and to provide sensitive indicators of environmental change, which can be used for monitoring purposes. The sedimentation of waste particles in the farm vicinities emerges as the main driver of benthic deterioration, such as accumulation of organic matter, sediment anoxia as well as seagrass decline. The effects of fish farming on P. oceanica meadows are diverse and complex and detected through various metrics and indicators. A safety distance of 400 m is suggested for management of P. oceanica near fish farms followed by establishment of permanent seagrass plots revisited annually for monitoring the health of the meadows.

  19. Effects of fish farm waste on Posidonia oceanica meadows: Synthesis and provision of monitoring and management tools

    International Nuclear Information System (INIS)

    Holmer, Marianne; Argyrou, Marina; Dalsgaard, Tage; Danovaro, Roberto; Diaz-Almela, Elena; Duarte, Carlos M.; Frederiksen, Morten; Grau, Antoni; Karakassis, Ioannis; Marba, Nuria; Mirto, Simone; Perez, Marta; Pusceddu, Antonio; Tsapakis, Manolis

    2008-01-01

    This paper provides a synthesis of the EU project MedVeg addressing the fate of nutrients released from fish farming in the Mediterranean with particular focus on the endemic seagrass Posidonia oceanica habitat. The objectives were to identify the main drivers of seagrass decline linked to fish farming and to provide sensitive indicators of environmental change, which can be used for monitoring purposes. The sedimentation of waste particles in the farm vicinities emerges as the main driver of benthic deterioration, such as accumulation of organic matter, sediment anoxia as well as seagrass decline. The effects of fish farming on P. oceanica meadows are diverse and complex and detected through various metrics and indicators. A safety distance of 400 m is suggested for management of P. oceanica near fish farms followed by establishment of permanent seagrass plots revisited annually for monitoring the health of the meadows

  20. Headwater Stream Management Dichotomies: Local Amphibian Habitat vs. Downstream Fish Habitat

    Science.gov (United States)

    Jackson, C. R.

    2002-12-01

    Small headwater streams in mountainous areas of the Pacific Northwest often do not harbor fish populations because of low water depth and high gradients. Rather, these streams provide habitat for dense assemblages of stream-dwelling amphibians. A variety of management goals have been suggested for such streams such as encouraging large woody debris recruitment to assist in sediment trapping and valley floor formation, encouraging large woody debris recruitment to provide downstream wood when debris flows occur, providing continuous linear stream buffers within forest harvest areas to provide shade and bank stability, etc. A basic problem with analying the geomorphic or biotic benefits of any of these strategies is the lack of explicit management goals for such streams. Should managers strive to optimize downstream fish habitat, local amphibian habitat, or both? Through observational data and theoretical considerations, it will be shown that these biotic goals will lead to very different geomorphic management recommendations. For instance, woody debris greater than 60 cm diameter may assist in valley floor development, but it is likely to create subsurface channel flow of unknown value to amphibians. Trapping and retention of fine sediments within headwater streams may improve downstream spawning gravels, but degrades stream-dwelling amphibian habitat. In response to the need for descriptive information on habitat and channel morphology specific to small, non-fish-bearing streams in the Pacific Northwest, morphologies and wood frequencies in forty-two first- and second-order forested streams less than four meters wide were surveyed. Frequencies and size distributions of woody debris were compared between small streams and larger fish-bearing streams as well as between second-growth and virgin timber streams. Statistical models were developed to explore dominant factors affecting channel morphology and habitat. Findings suggest geomorphological relationships

  1. CH4 Emission Model from Bos Primigenius Waste in Fish-Water: Implications for Integrated Livestock-Fish Farming Systems

    Directory of Open Access Journals (Sweden)

    Joshua O. Okeniyi

    2013-07-01

    Full Text Available This paper studies a methane (CH4 emission model from the waste of cattle (B. primigenius based on trends in integrated livestock-fish farming adoption by farmers in Nigeria. Dung of B. primigenius was employed as substrate in fish-water, obtained from a fish-rearing farm, as a matrix medium for simulating a low-oxygen wastewater environment of an agriculture-aquaculture system. A substrate to fish-water mass ratio of 1:3 was used, developed in a laboratory-size digesting reactor system. Volumetric readings, at ambient temperature conditions and with a retention time of thirty-two days, were then subjected to the logistic probability density function, and tested against correlation coefficient and Nash-Sutcliffe coefficient of efficiency criteria. The readings show that a volume of CH4-containing gas as high as 65.3 x 10−3 dm3 was produced on the 13th day from the B. primigenius substrate. Also, production of 234.59 x 10−3 dm3/kg CH4-containing gas, totaling 703.76 x 10−3 dm3, was observed through the studied retention time. The 60% CH4 constituent model of the measured gas generation showed a potency of 2.0664 kg emission per animal, which is equivalent to 43.3944 CO2eq of global warming potential (GWP annually per animal. This bears environmental and climate change implications, and therefore alternative sustainable practices for integrated livestock-fish farming adoption are suggested.

  2. MOLECULAR GENETIC MARKERS AND METHODS OF THEIR IDENTIFICATION IN MODERN FISH-FARMING

    Directory of Open Access Journals (Sweden)

    I. Hrytsyniak

    2014-03-01

    Full Text Available Purpose. The application of molecular genetic markers has been widely used in modern experimental fish-farming in recent years. This methodology is currently presented by a differentiated approach with individual mechanisms and clearly defined possibilities. Numerous publications in the scientific literature that are dedicated to molecular genetic markers for the most part offer purely practical data. Thus, the synthesis and analysis of existing information on the general principles of action and the limits of the main methods of using molecular genetic markers is an actual problem. In particular, such a description will make it possible to plan more effectively the experiment and to obtain the desired results with high reliability. Findings. The main types of variable parts of DNA that can be used as molecular genetic markers in determining the level of stock hybridization, conducting genetic inventory of population and solving other problems in modern fish-farming are described in this paper. Also, the article provides an overview of principal modern methods that can be used to identify molecular genetic markers. Originality. This work is a generalization of modern ideas about the mechanisms of experiments with molecular genetic markers in fish-farming. Information is provided in the form of consistent presentation of the principles and purpose of each method, as well as significant advances during their practical application. Practical value. The proposed review of classic and modern literature data on molecular genetic markers can be used for planning, modernization and correction of research activity in modern fish-farming.

  3. Growth of young Tabebuia aurea seedlings under irrigation with wastewater from fish farming

    Directory of Open Access Journals (Sweden)

    José R. de S. Pinto

    2016-06-01

    Full Text Available ABSTRACT This study aimed to evaluate the growth of young Tabebuia aurea seedlings irrigated with different concentrations of wastewater from fish farming. The experiment was conducted in a seedling nursery, from June to August 2013. The treatments consisted of five concentrations of wastewater from fish farming diluted in freshwater (0, 25, 50, 75 and 100% of wastewater. Plant height, stem diameter and plant height/stem diameter ratio were evaluated every 15 days to verify the effects of treatments on seedlings growth. At the end of the experiment, individual leaf area, leaf area, leaf dry matter, stem dry matter, root dry matter, total dry matter and Dickson quality index were also evaluated. The reuse of wastewater from fish farming diluted at concentrations of 25 and 50% in freshwater is a viable alternative in the production of Tabebuia aurea seedlings. However, higher concentrations hinder the production of seedlings of this species.

  4. Economic efficiency in fish farming: hope for agro-allied industries in Niagara

    Science.gov (United States)

    Kareem, R. O.; Dipeolu, A. O.; Aromolaran, A. B.; Williams, S. B.

    2008-02-01

    The challenge to increase the efficiency in food production level in Nigeria appears to be more urgent now than it has ever been in the history of the country. This is in view of the rapidly increasing population, the imminent decline in international economic and food aid and the need to conserve foreign exchange earnings through the production of raw materials to feed the growing industrial sector calls for urgent attention. The study was carried out in Ogun State. The descriptive statistics was used to determine the socio-economic characteristics of the respondents. The stochastic frontiers production analysis was applied to estimate the technical, allocative efficiency and economic efficiency among the fish farmers in the state. The results of economic efficiency revealed that fish farming is economically efficient with a range of between 55% and 84% efficiency level suggesting a favourable hope for the agro-allied industry such as poultry and cottage industries etc in the state. The result of hypothesis of inefficiency sources models showed that years of experience of fish farmers is significant at 1% probability level indicating the factor contributing to the fish farming experience in the state. Thus, the efficiency is due to the fact that farmers are experienced and fairly educated. On the basis of findings, policy is suggested to be directed towards the encouragement of entrepreneurs in fish farming in the state by providing enabling environment like credit facilities, public enlightenment programme and provision of social amenities like feeder roads, pipe-born water etc and given the fact that an increase in the level of formal education variable leads to less inefficiency, government policy should be focused on adopting the best technology (e.g. fast growing species and equipment) so as to improve the level of efficiency and investment which shall eventually lead to growth in output of fish farming and a lead to the establishment of agro

  5. Energy profiling of demersal fish: a case-study in wind farm artificial reefs.

    Science.gov (United States)

    De Troch, Marleen; Reubens, Jan T; Heirman, Elke; Degraer, Steven; Vincx, Magda

    2013-12-01

    The construction of wind farms introduces artificial hard substrates in sandy sediments. As Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus) tend to aggregate in order to feed around these reefs, energy profiling and trophic markers were applied to study their feeding ecology in a wind farm in the Belgian part of the North Sea. The proximate composition (carbohydrates, proteins and lipids) differed significantly between liver and muscle tissue but not between fish species or between their potential prey species. Atlantic cod showed to consume more energy than pouting. The latter had a higher overall energy reserve and can theoretically survive twice as long on the available energy than cod. In autumn, both fish species could survive longer on their energy than in spring. Polyunsaturated fatty acids were found in high concentrations in fish liver. The prey species Jassa and Pisidia were both rich in EPA while Jassa had a higher DHA content than Pisidia. Energy profiling supported the statement that wind farm artificial reefs are suitable feeding ground for both fish species. Sufficient energy levels were recorded and there is no indication of competition.

  6. Environmental consequence analyses of fish farm emissions related to different scales and exemplified by data from the Baltic--a review.

    Science.gov (United States)

    Gyllenhammar, Andreas; Håkanson, Lars

    2005-08-01

    The aim of this work is to review studies to evaluate how emissions from fish cage farms cause eutrophication effects in marine environments. The focus is on four different scales: (i) the conditions at the site of the farm, (ii) the local scale related to the coastal area where the farm is situated, (iii) the regional scale encompassing many coastal areas and (iv) the international scale including several regional coastal areas. The aim is to evaluate the role of nutrient emissions from fish farms in a general way, but all selected examples come from the Baltic Sea. An important part of this evaluation concerns the method to define the boundaries of a given coastal area. If this is done arbitrarily, one would obtain arbitrary results in the environmental consequence analysis. In this work, the boundary lines between the coast and the sea are drawn using GIS methods (geographical information systems) according to the topographical bottleneck method, which opens a way to determine many fundamental characteristics in the context of mass balance calculations. In mass balance modelling, the fluxes from the fish farm should be compared to other fluxes to, within and from coastal areas. Results collected in this study show that: (1) at the smallest scale (impact areas of fish cage farm often corresponds to the size of a "football field" (50-100 m) if the annual fish production is about 50 ton, (2) at the local scale (1 ha to 100 km2), there exists a simple load diagram (effect-load-sensitivity) to relate the environmental response and effects from a specific load from a fish cage farm. This makes it possible to obtain a first estimate of the maximum allowable fish production in a specific coastal area, (3) at the regional scale (100-10,000 km2), it is possible to create negative nutrient fluxes, i.e., use fish farming as a method to reduce the nutrient loading to the sea. The breaking point is to use more than about 1.1 g wet weight regionally caught wild fish per gram

  7. Effects of fish farm loadings on seagrass (Posidonia oceanica) distribution, growth and photosynthesis.

    Science.gov (United States)

    Ruiz, J M; Pérez, M; Romero, J

    2001-09-01

    The spatial extent and timing of the impact of fish farms on the distribution and performance of a Posidonia oceanica meadow were examined in an embayment of the south-eastern coast of Spain (Hornillo Bay, Murcia). Changes in seagrass distribution were determined using available seagrass mapping (from 1988, i.e., before the onset of aquaculture activities and 1998) and by successive sampling in 1994 and 1998. Environmental variables (light attenuation coefficient, water-column dissolved nutrients and organic content of sediments) together with plant performance (shoot biomass, leaf growth rate, photosynthetic activity, carbohydrate reserves, the number of leaves per shoot, epiphyte loads and herbivore pressure) were measured in plants affected by organic discharges, and were compared with those found in reference healthy plants over an annual growth cycle. Since the onset of fish farm activity, 11.29 ha of P. oceanica meadow has been completely lost and 9.86 ha significantly degraded, thus resulting in a total affected area which accounts for about 53% of the former meadow, or 7-fold the fish farming area. Unequal propagation of seagrass die-off or degradation reflects the relevance of local factors such as depth and hydrodynamism on the true extent of fish farm impact. Water transparency decreases and dissolved nutrient and organic content of sediments increases in the vicinity of cages compared to distant reference stations, thus supporting the notion of environmental gradients caused by the organic release from cages, which spreads outwards. Shoot size, leaf growth rate and the number of leaves per shoot in plants close to the fish farm decreased. Moreover, low leaf growth and low rhizome carbohydrate concentration (always relative to that found in an undisturbed area) indicated carbon budget imbalances. Since light reduction in the affected area was only modest (31% of light reaching the sea surface, while at the same depth this figure was 39% at the reference

  8. Physiological responses of the seagrass Posidonia oceanica as indicators of fish farm impact

    International Nuclear Information System (INIS)

    Perez, Marta; Garcia, Tania; Invers, Olga; Ruiz, Juan Manuel

    2008-01-01

    The development of aquaculture along the Mediterranean coastline degrades the marine environment, in particular Posidonia oceanica meadows, which, in extreme cases, show high mortality. Here we studied the effects of organic matter and nutrient input from the effluents of three fish farms, located along the Mediterranean coast, on P. oceanica physiology. For this purpose, we measured physiological variables such as total nitrogen (N) content, free amino acid (FAA) concentration and composition, N stable isotope ratio (δ 15 N), total phosphorus (P) content and total non-structural carbohydrate (TNC) content in plant tissues and epiphytes affected by organic discharges (highly impacted stations: HI, and less impacted stations: LI) and compared these results with those obtained in references sites (control stations: C). For all the descriptors analyzed in P. oceanica epiphytes, the values recorded in the vicinity of cages were, in general, much higher than those in C. Leaves did not respond consistently in any case. Total N content and δ 15 N in epiphytes together with the total P content in rhizomes and epiphytes were the physiological descriptors that showed the most consistent responses to fish farm effluents. On the basis of these observations, we conclude that fish farm activities strongly affect the physiological parameters of nearby P. oceanica meadows. We propose that changes in these physiological parameters may be useful indicators of marine environmental degradation in studies that monitor the effects of fish farming

  9. Physiological responses of the seagrass Posidonia oceanica as indicators of fish farm impact

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Marta [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain); Garcia, Tania [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain)], E-mail: irulagun@hotmail.com; Invers, Olga [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain); Ruiz, Juan Manuel [Instituto Espanol de Oceanografia C/Varadero 1, 30740 San Pedro del Pinatar, Murcia (Spain)

    2008-05-15

    The development of aquaculture along the Mediterranean coastline degrades the marine environment, in particular Posidonia oceanica meadows, which, in extreme cases, show high mortality. Here we studied the effects of organic matter and nutrient input from the effluents of three fish farms, located along the Mediterranean coast, on P. oceanica physiology. For this purpose, we measured physiological variables such as total nitrogen (N) content, free amino acid (FAA) concentration and composition, N stable isotope ratio ({delta}{sup 15}N), total phosphorus (P) content and total non-structural carbohydrate (TNC) content in plant tissues and epiphytes affected by organic discharges (highly impacted stations: HI, and less impacted stations: LI) and compared these results with those obtained in references sites (control stations: C). For all the descriptors analyzed in P. oceanica epiphytes, the values recorded in the vicinity of cages were, in general, much higher than those in C. Leaves did not respond consistently in any case. Total N content and {delta}{sup 15}N in epiphytes together with the total P content in rhizomes and epiphytes were the physiological descriptors that showed the most consistent responses to fish farm effluents. On the basis of these observations, we conclude that fish farm activities strongly affect the physiological parameters of nearby P. oceanica meadows. We propose that changes in these physiological parameters may be useful indicators of marine environmental degradation in studies that monitor the effects of fish farming.

  10. THE ENVIRONMENTAL IMPACTS OF MARINE FISH CAGE FARMS IN THE EASTERN ADRIATIC

    Directory of Open Access Journals (Sweden)

    Ivan Katavić

    2003-12-01

    Full Text Available Mariculture in Croatia could play a more important role in development of rural communities along coastline. However, by increase of fish farming, public concern over environmental issues has been raised, and the need for more responsible mariculture development and management has been asked. There are opportunities and challenges for effectively integrating mariculture into coastal zone management with equal rights and obligations. This is primarily because of its social and economic mission consisting in preventing de-population of rural coastal areas and islands and meeting the growing needs of tourist market for seafood. Although intensive mariculture production is accused of producing negative environmental effects, many of these effects still need to be scientifically documented. The effect of nitrogen and phosphorous releases from farmed fish faeces or uneaten food is not of significant issues for marine ecosystem, and it is generally of little importance compared to the inflow of nutrients from other coastal sources. The impact on sediment and benthic communities is mainly local and short-term ones, and depends on the number and extent of the farms and their location. Recovery of some benthic communities after the cessation of farming activities may be delayed over several years (i. e. Posidonia beds due to the accumulated organic matter. Bluefin tuna farming if not properly located and managed might cause pollution problems, either from uneaten feed and metabolic waste or from harvesting and processing the fish. In most cases the problem comes from smell pollution during the summer time and the oily water surface that may be widespread much outside of the farm areas. It will be important for sustainable development of Croatian mariculture to offer a healthy and good quality product in the quantities required by the market, while not degrading the marine environment.

  11. Seafood research from fish to dish : quality, safety and processing of wild and farmed fish

    NARCIS (Netherlands)

    Luten, J.B.

    2006-01-01

    In this book, scientists from various disciplines address the advances in seafood research with respect to quality, safety, consumer’s demands and processing of wild and farmed fish. The nutritional properties of marine lipids and lipid oxidation from model systems to seafood are presented. Several

  12. Fish Farm Challenge Provides STEM Design Experiences for Youth

    Science.gov (United States)

    Horton , Robert L.; House, Patty L.

    2015-01-01

    In 2014, Monsanto Corporation partnered with National 4-H Council to help inspire and develop professional skills among young agriculturalists. The Ohio State University created Fish Farm Challenge, which engaged more than 8,000 youth across eight states. Youth were taught about worldwide food insecurity and the importance of aquaculture. They…

  13. Increasing the Economical Efficiency and Sustainability of Indoor Fish Farming by Means of Aquaponics - Review

    Directory of Open Access Journals (Sweden)

    Flavius Blidariu

    2011-10-01

    Full Text Available This review focuses on increasing economical efficiency and sustainability of indoor fish farming. Aspects like sustainability and economical efficiency were reviewed. In order to improve man`s health we must reconsider the agricultural sciences, by this we understand that we must develop technologies friendly for the environment. Sustainable indoor fish farming is the farming of the new millennium. Combining aquaculture with hydroponics we obtain a new innovation named aquaponics which respects principles of sustainable agriculture (wastewater biofiltration by plants and gives us the possibility to increase economical efficiency with an additional production (organic vegetables.

  14. An overall estimation of losses caused by diseases in the Brazilian fish farms.

    Science.gov (United States)

    Tavares-Dias, Marcos; Martins, Maurício Laterça

    2017-12-01

    Parasitic and infectious diseases are common in finfish, but are difficult to accurately estimate the economic impacts on the production in a country with large dimensions like Brazil. The aim of this study was to estimate the costs caused by economic losses of finfish due to mortality by diseases in Brazil. A model for estimating the costs related to parasitic and bacterial diseases in farmed fish and an estimative of these economic impacts are presented. We used official data of production and mortality of finfish for rough estimation of economic losses. The losses herein presented are related to direct and indirect economic costs for freshwater farmed fish, which were estimated in US$ 84 million per year. Finally, it was possible to establish by the first time an estimative of overall losses in finfish production in Brazil using data available from production. Therefore, this current estimative must help researchers and policy makers to approximate the economic costs of diseases for fish farming industry, as well as for developing of public policies on the control measures of diseases and priority research lines.

  15. Microbial and nutritional aspects on the production of live feeds in a fish farming industry.

    Science.gov (United States)

    De Donno, A; Lugoli, F; Bagordo, F; Vilella, S; Campa, A; Grassi, T; Guido, M

    2010-03-01

    Aquaculture is an enterprise in constant development, in particular relating to its effect on the environment and also the quality of its products. It represents a valid alternative to traditional fishing, facing the increasing demand for fish products. To guarantee to the consumer a product of high nutritional, organoleptic and hygienic quality, it is fundamental to monitor every phase of the fish farming industry, isolating the potential risk points. For this reason there has been a rapid evolution of productive technique, particularly in the technology, artificial reproduction and feed sectors. The aim of this research has been the monitoring of the evolution of certain microbial and nutritional quality indexes (total microbial counts and lipid analysis on suspensions of Rotifers and Artemia, used as live feed) in the larval phase of the productive cycle of the farm raised fish, in an intensive system. The study has shown an increment in the total microbial counts in the fish farming industry within the production of Rotifers and Artemia, more evident in the suspensions of Rotifers. In addition the study has demonstrated that the maintenance phase, in the enrichment protocol, can reduce the EPA and DHA content. The results confirm the importance of microbial and nutritional control of the live feeds before they get supplied to fish larvae.

  16. An industry-scale mass marking technique for tracing farmed fish escapees.

    Directory of Open Access Journals (Sweden)

    Fletcher Warren-Myers

    Full Text Available Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and technical standards improved. Here, we tested if stable isotope otolith fingerprint marks delivered during routine vaccination could be an accurate, feasible and cost effective marking method, suitable for industrial-scale application. We tested seven stable isotopes, (134Ba, (135Ba, (136Ba, (137Ba, (86Sr, (87Sr and (26Mg, on farmed Atlantic salmon reared in freshwater, in experimental conditions designed to reflect commercial practice. Marking was 100% successful with individual Ba isotopes at concentrations as low as 0.001 µg. g-1 fish and for Sr isotopes at 1 µg. g-1 fish. Our results suggest that 63 unique fingerprint marks can be made at low cost using Ba (0.0002 - 0.02 $US per mark and Sr (0.46 - 0.82 $US per mark isotopes. Stable isotope fingerprinting during vaccination is feasible for commercial application if applied at a company level within the world's largest salmon producing nations. Introducing a mass marking scheme would enable tracing of escapees back to point of origin, which could drive greater compliance, better farm design and improved management practices to reduce escapes.

  17. The dinoflagellates Pfiesteria shumwayae and Luciella masanensis cause fish kills in recirculation fish farms in Denmark

    DEFF Research Database (Denmark)

    Moestrup, Øjvind; Hansen, Gert; Daugbjerg, Niels

    2014-01-01

    Fish kills in two geographically separate fish farms in northern Denmark in 2012, one using marine, the other brackish water 'Recirculation Aquaculture Systems' (RAS), were found to be caused by Pfiesteria shumwayae and Luciella masanensis, two species of dinoflagellates belonging to the family P...

  18. An Optimization Scheme for Water Pump Control in Smart Fish Farm with Efficient Energy Consumption

    Directory of Open Access Journals (Sweden)

    Israr Ullah

    2018-06-01

    Full Text Available Healthy fish production requires intensive care and ensuring stable and healthy production environment inside the farm tank is a challenging task. An Internet of Things (IoT based automated system is highly desirable that can continuously monitor the fish tanks with optimal resources utilization. Significant cost reduction can be achieved if farm equipment and water pumps are operated only when required using optimization schemes. In this paper, we present a general system design for smart fish farms. We have developed an optimization scheme for water pump control to maintain desired water level in fish tank with efficient energy consumption through appropriate selection of pumping flow rate and tank filling level. Proposed optimization scheme attempts to achieve a trade-off between pumping duration and flow rate through selection of optimized water level. Kalman filter algorithm is applied to remove error in sensor readings. We observed through simulation results that optimization scheme achieve significant reduction in energy consumption as compared to the two alternate schemes, i.e., pumping with maximum and minimum flow rates. Proposed system can help in collecting the data about the farm for long-term analysis and better decision making in future for efficient resource utilization and overall profit maximization.

  19. Expanding the moral circle: farmed fish as objects of moral concern.

    Science.gov (United States)

    Lund, Vonne; Mejdell, Cecilie M; Röcklinsberg, Helena; Anthony, Ray; Håstein, Tore

    2007-05-04

    Until recently fish welfare attracted little attention, but international and national legislation and standards of fish welfare are now emerging and an overview of these developments is presented in this study. Whereas animal welfare legislation is based on public morality, animal ethics does not automatically accept public morality as normative and elaborates arguments regarding the way humans should treat animals (referred to as moral standards). In this study we present the most common animal ethics theories. For most of these, sentience is considered a demarcation line for moral concern: if an animal is sentient, then it should be included in the moral circle, i.e. receive moral consideration in its own right and some basic welfare should be ensured. As for fish, research has revealed that the sensory system of teleosts can detect noxious stimuli, and that some kind of phenomenal consciousness, allowing the fish to feel pain, seems to be present. This raises the ethical question as to how much evidence we need in order to act on such indications of fish sentience. A simple risk analysis shows that the probability that fishes can feel pain is not negligible and that if they do indeed experience pain the consequences in terms of the number of suffering individuals are great. We conclude that farmed fish should be given the benefit of the doubt and we should make efforts that their welfare needs are met as well as possible. Finally, the way forward is briefly discussed: efforts must be made to understand what fish welfare means in practical fish farming. This will involve the development of research and education, greater accountability and transparency, compliance with and control of policies, and quality assurance schemes.

  20. Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming.

    Science.gov (United States)

    Besson, M; de Boer, I J M; Vandeputte, M; van Arendonk, J A M; Quillet, E; Komen, H; Aubin, J

    2017-01-01

    In sea cage fish farming, production quotas aim to constrain the impact of fish farming on the surrounding ecosystem. It is unknown how these quotas affect economic profitability and environmental impact of genetic improvement. We combined bioeconomic modelling with life cycle assessment (LCA) to calculate the economic (EV) and environmental (ENV) values of thermal growth coefficient (TGC) and feed conversion ratio (FCR) of sea bass reared in sea cages, given four types of quota commonly used in Europe: annual production (Qprod), annual feed distributed (Qannual_feed), standing stock (Qstock), and daily feed distributed (Qdaily_feed). ENV were calculated for LCA impact categories climate change, eutrophication and acidification. ENV were expressed per ton of fish produced per year (ENV(fish)) and per farm per year (ENV(farm)). Results show that irrespective of quota used, EV of FCR as well as ENV(fish) and ENV(farm) were always positive, meaning that improving FCR increased profit and decreased environmental impacts. However, the EV and the ENV(fish) of TGC were positive only when quota was Qstock or Qdaily_feed. Moreover, the ENV(farm) of TGC was negative in Qstock and Qdaily_feed quotas, meaning that improving TGC increased the environmental impact of the farm. We conclude that Qstock quota and Qdaily_feed quota are economically favorable to a genetic improvement of TGC, a major trait for farmers. However, improving TGC increases the environmental impact of the farm. Improving FCR represents a good opportunity to balance out this increase but more information on its genetic background is needed to develop breeding programs improving FCR.

  1. Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming.

    Directory of Open Access Journals (Sweden)

    M Besson

    Full Text Available In sea cage fish farming, production quotas aim to constrain the impact of fish farming on the surrounding ecosystem. It is unknown how these quotas affect economic profitability and environmental impact of genetic improvement. We combined bioeconomic modelling with life cycle assessment (LCA to calculate the economic (EV and environmental (ENV values of thermal growth coefficient (TGC and feed conversion ratio (FCR of sea bass reared in sea cages, given four types of quota commonly used in Europe: annual production (Qprod, annual feed distributed (Qannual_feed, standing stock (Qstock, and daily feed distributed (Qdaily_feed. ENV were calculated for LCA impact categories climate change, eutrophication and acidification. ENV were expressed per ton of fish produced per year (ENV(fish and per farm per year (ENV(farm. Results show that irrespective of quota used, EV of FCR as well as ENV(fish and ENV(farm were always positive, meaning that improving FCR increased profit and decreased environmental impacts. However, the EV and the ENV(fish of TGC were positive only when quota was Qstock or Qdaily_feed. Moreover, the ENV(farm of TGC was negative in Qstock and Qdaily_feed quotas, meaning that improving TGC increased the environmental impact of the farm. We conclude that Qstock quota and Qdaily_feed quota are economically favorable to a genetic improvement of TGC, a major trait for farmers. However, improving TGC increases the environmental impact of the farm. Improving FCR represents a good opportunity to balance out this increase but more information on its genetic background is needed to develop breeding programs improving FCR.

  2. PMCV and PRV occurrence in wild and farmed fish in Denmark

    DEFF Research Database (Denmark)

    Mikkelsen, Susie Sommer; Arnö, J.; Bruun, Morten Sichlau

    Every year salmon are restocked in the 7 rivers Storå, Skjern Å, Varde Å, Sneum Å, Kongeå, Ribe Å and Gudenåen. Six-month-old and 1-year-old salmon for about 2 mio. Kr (€268000) are restocked every year. The salmon are restocked in both the main rivers as well as the larger inlets. 6-month-old sa...... fish were tested by real-time RT-PCR for PRV and 30 fish from each river were tested by real-time RT-PCR for PMCV. This is the first time wild and farmed fish have been tested for either virus in Denmark.......-virus in the family of Reoviridae, while Piscine myocarditis virus (PMCV) is a double-stranded RNA virus of the Totiviridae family. Wild and farmed salmon and trout have not been tested for PRV or PMCV in Denmark before, but both viruses are found in Norway, where they are suspected of causing Heart and Skeletal...... Muscle Inflammation (HSMI) and Cardiomyopathy Syndrome (CMS), respectively. In 2013, broodstock from four different rivers in Denmark were received for surveillance. These rivers are Ribe, Varde, Skjern and Store Å, which are all west-facing rivers. Of these fish 8 were Sea Trout and the rest Salmon. 184...

  3. Total lipids and fatty acid profile in the liver of wild and farmed catla catla fish

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, M.; Shaihid chatha, S. A.; Tahira, I.; Hussain, B.

    2010-07-01

    This experimental work was aimed to study the moisture content, total lipids and fatty acid profile in the liver of wild and farmed freshwater major carp Catla catla of three different weight categories designated as W{sub 1} (601-900g), W{sub 2} (901- 1200)g and W{sub 3} (1201-1500g). Seven fish specimens of each of the three weight categories of wild and farmed Catla catla were obtained from Trimu Head, Jhang and Fish Hatchery, Satiana Road and Faisalabad, respectively. The fish were dissected to remove the liver and after weighing, liver samples were prepared and subjected to chemical analysis. Wild Catla catla liver had a significantly (p <0.05) higher moisture content as compared to the farmed species. Farmed Catla catla deposited significantly (p < 0.05) higher lipid contents in liver. Proportions of saturated fatty acids varied irregularly in the lipids of the liver from both wild and farmed Catla catla. Saturated fatty acids C12:0, C14:0, C16:0, C18:0, C20:0 and C22:0 were identified with considerable percentages in the liver of Catla catla from both habitats and monounsaturated fatty acid C18:1 was found in considerable amounts in the liver of both major carp. Polyunsaturated fatty acids such as C18:3 (n-6) and C20: 2 (n-6) were detected in the liver of the wild fish of W{sub 2} and W{sub 3} and was similar in the W{sub 3} weight category of the farmed species. (Author) 22 refs.

  4. Assessment of the effects of cage fish-farming on damselfish-associated food chains using stable-isotope analyses

    International Nuclear Information System (INIS)

    Jan, Rong-Quen; Kao, Shuh-Ji; Dai, Chang-Feng; Ho, Cheng-Tze

    2014-01-01

    Highlights: • Damselfishes living at sites near a cage farm bore lower δ 13 C and higher δ 15 N. • Similar trends occurred in zooplankton and detritus, major foods for damselfishes. • δ 15 N enrichment in fish may have arisen from the uptake of excess feed and prey. • Farm wastes were documented entering the ecosystem through the pelagic food chain. • No clear evidence of the effects of cage farming on stable isotopes in macroalgae. - Abstract: To assess the effect of cage fish-farming on the coral reef ecosystem off Xiaoliuchiu Island, southern Taiwan, geographical differences in the food chain of each of two damselfishes, Pomacentrus vaiuli and Chromis margaritifer, were examined using a stable-isotope approach. For each damselfish, individuals were found to consume similar foods at all sites. However, specimens collected at sites near the cage farm (as the experimental sites) exhibited lower δ 13 C and higher δ 15 N signatures compared to those from reference sites. Similar trends also occurred in the zooplankton and detritus, two major food sources for both damselfishes. This finding indicates that particulate organic matter released by the farm may have entered the coral reef ecosystem through the pelagic food chain. Artificial reef emplacement is recommended to provide extra habitats under cage farms to support additional pelagic-feeding fish populations, thereby reducing environmental impacts of cage farming on coral reefs

  5. Farming a new economically viable fish species: Kisinja (Barbus altianalis)

    OpenAIRE

    Aruho, C.; Ondhoro, C.C.

    2010-01-01

    Kisinja (Barbus altianalis)is an indigenous omnivorous fish, of high economic value in Uganda. It was widely distributed in most lakes and rivers in the country but its stocks were depleted due to overfishing and degradation of its natural habitat. 1t can grow up to a maximum length of 120m and a weight of 15kg in the wild and grows faster, attains larger size than commonly farmed fishes in Uganda, including the Nile tilapia, the African catfish, and mirror carp. Kisinja is a highly valuable ...

  6. Analysis of Goat Farming on Integrated Farming System in Banyumas

    Directory of Open Access Journals (Sweden)

    NN Hidayat

    2007-05-01

    Full Text Available The objective of this research were : 1 to find out the income generated from goat farming and its contribution to farmer income in several farming combination, 2 to find out the economic efficiency in goat farming with paddy and fish production, 3 to determine factors affecting level of production and income in different farming system, partially and aggregately, and 4 to determine the best combination of farming which generated maximum income. Household farmer survey method was performed to conduct this research. Farming model chosen in this research was partial and average aggregate. Cobb-Douglas function were chosen to predict functional relationship. Result stated from this research were : 1 goat farming has a significant contribution in integrated farming system, 2 integrated farming (goat and paddy, goat and fish, and goat, fish and paddy in Banyumas district was economically efficient. 3 partially, factor affecting production level in goat farming was number of goat owned (P<0.01, factor affecting paddy production were urea application and number of land owned (P<0.01, TSP application (P<0.05 and man power (P<0.10. Furthermore, factor affecting fish farming were feed, breed and number of land owned (P<0.01; 4 aggregately, factor affecting integrated farming I were urea application and number of land owned (P<0.01, feed and number of land owned (P<0.01, number of goat owned (P<0.10 integrated farming II, where as in integrated farming III were number of paddy land area and breed (P<0.01 also number of goat owned (P<0.10; 5 integrated farming III (goat, paddy and fish farming gave the highest profit, which gave Rp 6.219.283,81 with relatively high efficiency. Therefore, goat farming could be an alternative solution to be developed in integrated farming and could be combined with other farming activities such as paddy and fish farming. (Animal Production 9(2: 105-110 (2007 Key Words : Goat, income, economic efficiency, survey, contribution

  7. The advancement of probiotics research and its application in fish farming industries.

    Science.gov (United States)

    Banerjee, Goutam; Ray, Arun Kumar

    2017-12-01

    Fish are always susceptible to a variety of lethal diseases caused by different types of bacterial, fungal, viral and parasitic agents. The unscientific management practises such as, over feeding, high stock densities and destructive fishing techniques increase the probability of disease symptoms in aquaculture industries. According to Food and Agriculture Association (FAO), each and every year several countries such as China, India, Norway, Indonesia, etc. face a huge loss in aquaculture production due to mainly bacterial and viral diseases. The use of antibiotics is a common practise in fish farming sectors to control the disease outbreak. However, the antibiotics are not long term friend because it creates selective pressure for emergence of drug resistant bacteria. Probiotics are live microorganisms that confer several beneficial effects to host (enhances immunity, helps in digestion, protects from pathogens, improves water quality, promotes growth and reproduction) and can be used as an alternative of antibiotics. In recent year, a wide range of bacteria have reported as potential probiotics candidates in fish farming sectors, however, Lactobacillus sp. and Bacillus sp. gain special attention due to their high antagonistic activities, extracellular enzyme production and availability. In this present review, we have summarized the recent advancement in aquaculture probiotics research and its impact on fish health, nutrition, immunity, reproduction and water quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Parasites of marine, freshwater and farmed fishes of Portugal: a review

    Directory of Open Access Journals (Sweden)

    Jorge da Costa Eiras

    Full Text Available Abstract An extensive literature review is made of the parasites in marine and freshwater fish in mainland Portugal, the Portuguese archipelagos of the Azores and Madeira, as well as in farmed fish. The host(s of each parasite species, its location in the host, site of capture of the host, whenever possible, and all the available bibliographic references are described. The economic importance of some parasites and the zoonotic relevance of some parasitic forms are discussed. A general overview of the data is provided, and some research lines are suggested in order to increase and complement the current body of knowledge about the parasites of fish from Portugal.

  9. Effect of the rearing tank residue of fish farms on the production of passion fruit tree seedlings

    Directory of Open Access Journals (Sweden)

    F. O. R. Silva

    2017-03-01

    Full Text Available The objective of this study was to evaluate the initial growth of seedlings and biomass production of blue and yellow passion fruit trees (round cultivar produced from residue of the rearing tanks of fish farms. The experiment was conducted in a greenhouse using residue obtained from fish farming tanks. Ravine soil (RS, fish tank residue (FR and Tropstrato (TR were used as substrate. The treatments were: T1 = control consisting of Tropstrato substrate; T2 = 25% FR + 75% RS; T3 = 50% FR + 50% RS; T4 = 25% RS + 75% FR; T5 = 100% FR. A completely randomized block design consisting of 5 treatments, 4 replicates and 11 plants per plot was used. Treatment T5 (100% fish farming residue resulted in the largest average number of leaves, highest dry matter production of the aerial part, and highest dry matter accumulation in the root (P<0.05. The worst results were obtained for the treatment using 25% FR (T2, which resulted in less uniformity of the variables studied. Stem height of the passion fruit tree was greater for the treatments that included FR, with the greatest mean height being observed for T5. In conclusion, the treatment using the residue of fish farming tanks was found to be beneficial to produce yellow passion fruit seedlings (round cultivar, representing a good alternative for the reutilization of this residue.

  10. Influence of water temperature on the economic value of growth rate in fish farming

    NARCIS (Netherlands)

    Besson, M.; Vandeputte, M.; Arendonk, van J.A.M.; Aubin, J.; Boer, de I.J.M.; Quillet, E.; Komen, H.

    2016-01-01

    In sea cage farming, fish are exposed to seasonal variations of water temperature, and these variations can differ from one location to another. A small increase in water temperature does not only stimulate growth of the fish (until an optimal level) but also lowers dissolved oxygen concentration

  11. Yersiniosis outbreak in rainbow trout at fish farm in Oromia Regional ...

    African Journals Online (AJOL)

    This study showed the importance of stress induced by higher temperature and poor water quality associated with infestations by Trichodina species as predisposing factors to bacterial diseases in intensive fish farming practices. Key words: bacterial culture, histopathology, rainbow trout, Yersinia ruckeri, Trichodina species ...

  12. Environmental impacts of genetic improvement of growth rate and feed conversion ratio in fish farming under rearing density and nitrogen output limitations

    NARCIS (Netherlands)

    Besson, M.; Aubin, J.; Komen, H.; Poelman, M.; Quillet, E.; Vandeputte, M.; Arendonk, Van J.A.M.; Boer, De I.J.M.

    2016-01-01

    Today, fish farming faces an increasing demand in fish products, but also various environmental challenges. Genetic improvement in growth rate and feed conversion ratio is known to be an efficient way to increase production and increase efficiency in fish farming. The environmental consequences

  13. Experimental infection of rainbow trout Oncorhynchus mykiss with viral haemorrhagic septicaemia virus isolates from European marine and farmed fishes

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Slierendrecht, W.J.; King, J.A.

    2004-01-01

    The susceptibility of rainbow trout Oncorhynchus mykiss to infection with various isolates of viral haemorrhagic septicaemia virus (VHSV) was examined. A total of 8 experiments with rainbow trout ranging from 0.6 to 6.2 g was conducted for 139 isolates originating from wild marine fishes in Europ......The susceptibility of rainbow trout Oncorhynchus mykiss to infection with various isolates of viral haemorrhagic septicaemia virus (VHSV) was examined. A total of 8 experiments with rainbow trout ranging from 0.6 to 6.2 g was conducted for 139 isolates originating from wild marine fishes...... in European waters (115 isolates), farmed turbot from Scotland and Ireland (2 isolates), and farmed rainbow trout (22 isolates). The isolates were tested by immersion and/or intraperitoneal injection either as pooled or single isolates. The isolates from wild marine fishes did not cause mortality by immersion...... while some of the isolates caused mortality when injected. All VHSV isolates from farmed rainbow trout caused significant mortality by immersion. Currently, pathogenicity trials are the only way to differentiate VHSV isolates from wild marine fishes and farmed rainbow trout. The 2 farmed turbot isolates...

  14. Hermetia illucens meal as fish meal replacement for rainbow trout on farm

    OpenAIRE

    Stadtlander, Timo; Stamer, Andreas; Buser, Andrea; Wohlfahrt, Jens; Leiber, Florian; Sandrock, Christoph

    2017-01-01

    In a 7-week on-farm feeding trial rainbow trout (Oncorhynchus mykiss) were provided with a diet containing 28% mechanically de-fatted insect meal prepared from larvae of the black soldier fly, Hermetia illucens (HIM) and compared to a control that received a certified organic and fishmeal based diet. In the test diet insect meal replaced almost 50% of the fishmeal. The whole experiment was conducted under practical conditions on an organically certified rainbow trout farm in Switzerland. Fish...

  15. THE INFORMATIONAL SYSTEM FOR RESOURSES ADMINISTRATION IN FISH FARMS

    Directory of Open Access Journals (Sweden)

    Adrian ZUGRAVU

    2005-01-01

    Full Text Available The informational system for aquaculture activities provide a financial planning and analysis tool.The software can also be of assistance to land-based farmers who want to more thoroughly utilizetheir water resources by developing small-scale fish farm systems to provide supplementary income.Informational model has been enhanced to produce a comprehensive software package foraquaculture feasibility modeling, financial planning, sales and harvesting planning and managementinformation tools.

  16. Poultry as reservoir hosts for fishborne zoonotic trematodes in Vietnamese fish farms.

    Science.gov (United States)

    Anh, Nguyen Thi Lan; Madsen, Henry; Dalsgaard, Anders; Phuong, Nguyen Thi; Thanh, Dao Thi Ha; Murrell, K Darwin

    2010-05-11

    Fishborne zoonotic trematodes (FZT) are widespread in Vietnam and Southeast Asia. It is now recognized that the risk of being infected from eating raw fish dishes applies not only to humans, but also to domestic animals (e.g., cats, dogs, and pigs) and fish-eating birds. The role of ducks and chicken, commonly raised on fish farms, as reservoir hosts, however, has not been adequately investigated. To study this question, chickens and ducks from integrated poultry-fish farms in Nghia Lac and Nghia Phu communes, Nam Dinh province, Vietnam were surveyed for FZT infections. A total of 50 ducks and 50 chickens from each commune were examined. Results revealed that 12% of chickens and 30% of ducks were infected with various species of trematodes, including two zoonotic species, Centrocestus formosanus and Echinostoma cinetorchis. Both occurred in chickens whereas only E. cinetorchis was found in ducks. Prevalence of these zoonotic species was 12% and 7% in ducks and chickens, respectively. Among other trematodes, Hypoderaeum conoideum, also a zoonotic fluke, was the most prevalent (20-30%). The feeding of snails and fish remains to poultry, either intentionally or by discharge of waste from the slaughter of ducks and chickens into the ponds, was identified as risk factors for trematode infection. The FZT species and low prevalence found in poultry in these communes indicate their role as reservoir hosts is minor. (c) 2010 Elsevier B.V. All rights reserved.

  17. Occupational asthma caused by turbot allergy in 3 fish-farm workers.

    Science.gov (United States)

    Pérez Carral, C; Martín-Lázaro, J; Ledesma, A; de la Torre, F

    2010-01-01

    We report 3 patients (26, 31, and 33 years) who worked at the same fish farm for several years. They experienced symptoms of rhinoconjunctivitis and bronchial asthma while classifying fish by size. Their asthma gradually worsened to the extent that it became persistent and required daily medication with inhaled corticosteroids and bronchodilators. Symptoms improved during weekends and holidays. All 3 patients could eat turbot. Our study showed that the patients were allergic and that sensitization was probably by inhalation. The allergens were parvalbumin in 1 case and a different allergen in the remaining 2 patients.

  18. Using copper sulfate to control egg fungus at Keo Fish Farm

    Science.gov (United States)

    Keo Fish Farm is the biggest producer of hybrid striped bass fry in the world. The hatchery manager asked about treatments to control fungus on eggs which occurred fairly often. Our lab has been working on gaining FDA-approval to use copper sulfate to control fungus on catfish eggs, so we were con...

  19. Urtica dioica (Stinging Nettle): A Neglected Plant With Emerging Growth Promoter/Immunostimulant Properties for Farmed Fish.

    Science.gov (United States)

    De Vico, Gionata; Guida, Vincenzo; Carella, Francesca

    2018-01-01

    Urtica dioica (stinging nettle), is a perennial plant belonging to the family of Urticaceae , genus Urtica . Despite the use of nettle in folk veterinary medicine is well documented, U. dioica is today an underestimated and frequently neglected plant, considered by the contemporary agriculture as a weed to be eliminated. This mini review focus on very recent studies on dietary administration of U. dioica , both as a single herb or in combination with other herbs, to enhance growth and stimulate farmed fish immunity, thus enabling the fish to be more resistant against bacterial infections. Such an emerging feature, together with cost-effectiveness, adequate availability, and easy processing of nettle, could make this herb an excellent, inexpensive and widely used dietary supplement on intensive fish farms.

  20. Urtica dioica (Stinging Nettle): A Neglected Plant With Emerging Growth Promoter/Immunostimulant Properties for Farmed Fish

    Science.gov (United States)

    De Vico, Gionata; Guida, Vincenzo; Carella, Francesca

    2018-01-01

    Urtica dioica (stinging nettle), is a perennial plant belonging to the family of Urticaceae, genus Urtica. Despite the use of nettle in folk veterinary medicine is well documented, U. dioica is today an underestimated and frequently neglected plant, considered by the contemporary agriculture as a weed to be eliminated. This mini review focus on very recent studies on dietary administration of U. dioica, both as a single herb or in combination with other herbs, to enhance growth and stimulate farmed fish immunity, thus enabling the fish to be more resistant against bacterial infections. Such an emerging feature, together with cost-effectiveness, adequate availability, and easy processing of nettle, could make this herb an excellent, inexpensive and widely used dietary supplement on intensive fish farms. PMID:29632497

  1. Survival of juvenile chinook salmon and coho salmon in the Roza Dam fish bypass and in downstream reaches of the Yakima River, Washington, 2016

    Science.gov (United States)

    Kock, Tobias J.; Perry, Russell W.; Hansen, Amy C.

    2016-12-22

    Estimates of juvenile salmon survival are important data for fishery managers in the Yakima River Basin. Radiotelemetry studies during 2012–14 showed that tagged juvenile Chinook salmon (Oncorhynchus tshawytscha) that passed through the fish bypass at Roza Dam had lower survival than fish that passed through other routes at the dam. That study also identified flow-survival relationships in the reaches between the Roza Dam tailrace and Sunnyside Dam. During 2012–14, survival also was estimated through reaches downstream of Sunnyside Dam, but generally, sample sizes were low and the estimates were imprecise. In 2016, we conducted an evaluation using acoustic cameras and acoustic telemetry to build on information collected during the previous study. The goal of the 2016 research was to identify areas where mortality occurs in the fish bypass at Roza Dam, and to estimate reach-specific survival in reaches downstream of the dam. The 2016 study included juvenile Chinook salmon and coho salmon (O. kisutch).Three acoustic cameras were used to observe fish behavior (1) near the entrances to the fish bypass, (2) at a midway point in the fish bypass (convergence vault), and (3) at the bypass outfall. In total, 504 hours of acoustic camera footage was collected at these locations. We determined that smolt-sized fish (95–170 millimeters [mm]) were present in the highest proportions at each location, but predator-sized fish (greater than 250 mm) also were present at each site. Fish presence generally peaked during nighttime hours and crepuscular periods, and was low during daytime hours. In the convergence vault, smolt-sized fish exhibited holding behavior patterns, which may explain why some fish delayed while passing through the bypass.Some of the acoustic-tagged fish were delayed in the fish bypass following release, but there was no evidence to suggest that they experienced higher mortality than fish that were released at the bypass outfall or downstream of the dam

  2. Epidemic and Endemic Malaria Transmission Related to Fish Farming Ponds in the Amazon Frontier.

    Directory of Open Access Journals (Sweden)

    Izabel Cristina Dos Reis

    Full Text Available Fish farming in the Amazon has been stimulated as a solution to increase economic development. However, poorly managed fish ponds have been sometimes associated with the presence of Anopheles spp. and consequently, with malaria transmission. In this study, we analyzed the spatial and temporal dynamics of malaria in the state of Acre (and more closely within a single county to investigate the potential links between aquaculture and malaria transmission in this region. At the state level, we classified the 22 counties into three malaria endemicity patterns, based on the correlation between notification time series. Furthermore, the study period (2003-2013 was divided into two phases (epidemic and post-epidemic. Higher fish pond construction coincided both spatially and temporally with increased rate of malaria notification. Within one malaria endemic county, we investigated the relationship between the geolocation of malaria cases (2011-2012 and their distance to fish ponds. Entomological surveys carried out in these ponds provided measurements of anopheline abundance that were significantly associated with the abundance of malaria cases within 100 m of the ponds (P < 0.005; r = 0.39. These results taken together suggest that fish farming contributes to the maintenance of high transmission levels of malaria in this region.

  3. Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

    Directory of Open Access Journals (Sweden)

    Florent Chazarenc

    2010-08-01

    Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

  4. Synthesis of downstream fish passage information at projects owned by the U.S. Army Corps of Engineers in the Willamette River Basin, Oregon

    Science.gov (United States)

    Hansen, Amy C.; Kock, Tobias J.; Hansen, Gabriel S.

    2017-08-07

    The U.S. Army Corps of Engineers (USACE) operates the Willamette Valley Project (Project) in northwestern Oregon, which includes a series of dams, reservoirs, revetments, and fish hatcheries. Project dams were constructed during the 1950s and 1960s on rivers that supported populations of spring Chinook salmon (Oncorhynchus tshawytscha), winter steelhead (O. mykiss), and other anadromous fish species in the Willamette River Basin. These dams, and the reservoirs they created, negatively affected anadromous fish populations. Efforts are currently underway to improve passage conditions within the Project and enhance populations of anadromous fish species. Research on downstream fish passage within the Project has occurred since 1960 and these efforts are documented in numerous reports and publications. These studies are important resources to managers in the Project, so the USACE requested a synthesis of existing literature that could serve as a resource for future decision-making processes. In 2016, the U.S. Geological Survey conducted an extensive literature review on downstream fish passage studies within the Project. We identified 116 documents that described studies conducted during 1960–2016. Each of these documents were obtained, reviewed, and organized by their content to describe the state-of-knowledge within four subbasins in the Project, which include the North Santiam, South Santiam, McKenzie, and Middle Fork Willamette Rivers. In this document, we summarize key findings from various studies on downstream fish passage in the Willamette Project. Readers are advised to review specific reports of interest to insure that study methods, results, and additional considerations are fully understood.

  5. Stunning and killing of farmed fish: How to put it into pratice?

    NARCIS (Netherlands)

    Vis, van de J.W.; Abbink, W.; Lambooij, B.; Bracke, M.B.M.

    2014-01-01

    In this article an approach is presented to implement stunning and killing of farmed fish in practice. First, in a laboratory setting, the conditions need to be established to achieve an effective stun without causing avoidable distress and discomfort. Product quality is evaluated to assess the

  6. BACTERIOLOGICAL PROPERTIES OF MARINE WATER IN ADRIATIC FISH FARMS: ENUMERATION OF HETEROTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Emin Teskeredžić

    2012-12-01

    Full Text Available Aquaculture is currently one of the fastest growing food production sectors in the world. Increase in nutrients and organic wastes lead to general deterioration of water quality. The problem of water quality is associated with both physical and chemical factors, as well as microbiological water quality. Heterotrophic bacteria play an important role in the process of decomposition of organic matter in water environment and indicate eutrophication process. Here we present our experience and knowledge on bacterial properties of marine water in the Adriatic fish farms with European sea bass (Dicentrarchus labrax L., 1758, with an emphasis on enumeration of heterotrophic bacteria in marine water. We applied two temperatures of incubation, as well as two methods for enumeration of heterotrophic bacteria: substrate SimPlate® test and spread plate method on conventional artificial media (Marine agar and Tryptic Soy agar with added NaCl. The results of analysis of bacteriological properties of marine water in the Adriatic fish farms showed that enumeration of heterotrophic bacteria in marine water depends on the applied incubation temperature and media for enumeration. At the same time, the incubation temperature of 22C favours more intense growth of marine heterotrophic bacteria, whereas a SimPlate test gives higher values of heterotrophic bacteria. Volatile values of heterotrophic bacteria during this research indicate a possible deterioration of microbiological water quality in the Adriatic fish farms and a need for regular monitoring of marine water quality.

  7. Review: importance of establishing and running a breeding program in the developing fish farming industry

    OpenAIRE

    Agim Rexhepi; Kurtesh Sherifi; Hysen Bytyqi; Behlul Behluli

    2013-01-01

    Fish farming in developing countries including the Republic of Kosova is largely based on unimproved fish strains. In aquaculture research the main focus has been on increasing productivity through improvements in management, technology, disease control etc. Anyhow, is accepted worldwide that the full benefits can be obtained thorough genetically improved fish. In many countries are given evidence indicating the potential of genetic improvement programs and a range of selection methods may be...

  8. Distribution of fish species for the generic Appropriate Assessment for the construction of offshore wind farms.

    NARCIS (Netherlands)

    Hofstede, ter R.; Winter, H.V.; Os, O.G.

    2008-01-01

    The Dutch government aims at the production of 450 MW of electricity by offshore wind farms by 2010 and 6000 MW by 2020. Possibly the construction, exploitation and dismantlement of the wind farms will influence fish in the North Sea, which are protected under the European Habitat Directive or are

  9. Fish farm and water quality management - doi: 10.4025/actascibiolsci.v35i1.10086

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Sipaúba Tavares

    2012-12-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 Fish farms’ water quality management is analyzed with regard to the management employed and the different trophic states are compared within the system during the dry and rainy seasons. Six sites were marked two in the water supply (P1 and P2, and four within the fish farm (P3 to P6 . Whereas sites P1 and P2 (water supply were characterized as oligotrophic, the others were mesotrophic and eutrotrophic sites. Environmental variables, mainly nutrients, conductivity, COD, BOD5 and TSS tended to increase as from P3 due to management and fertilization. Greater impact has been registered in the fish farm under analysis for variables COD, ammonia, total phosphorus and TSS during the discharge and pond emptying period. Frequent monitoring of water quality should be undertaken in fish breeding and plankton production ponds, especially in those close to P3 and P4. Removal of sediment in decantation lake or P5 is also recommended to decrease nutrient concentrations, especially phosphorus, accumulated on the bottom soil.

  10. Description age-3 brood rainbow trout bred in the conditions of the industral fish farm "Sloboda Banyliv"

    Directory of Open Access Journals (Sweden)

    P. Mendryshora

    2017-06-01

    Full Text Available Purpose. To analyze the results of cultivation and give fish-breeding and biological characteristics of age-3 brood rainbow trout grown using industrial technology in the conditions of the trout farm "Sloboda Banyliv." Methodology. Fish cultivation was carried in tank conditions of the trout farm "Sloboda Banyliv". The material for the study were age-3 brood rainbow trout obtained from eggs of the fall-spawning form of rainbow trout. Cultivation was carried out in a 216 m2 tank, stocking density of 255 fish/m2, using standard trout culture methods. Statistical analysis of the material was performed in Microsoft Office Excel (2003. Analysis of the variables was performed in the system of absolute values. The analysis criteria were their mean values mean deviations (M±m, standard error (σ, variability coefficient (Cv. Fish were fed with specialized feed manufactured by “BioMar” (Denmark with a high protein content (more than 40%. Findings. Based on the performed selective-breeding works aimed at creating brood stocks of rainbow trout, it was found that brood fish reared in the industrial conditions of the fish farm “Sloboda Banyliv”, despite instable culture conditions, were characterized by a moderate growth rate and had high values of productive and reproductive features. Mean weight of age-3 rainbow trout females was 1282.5 g, fecundity — 3.48 thousand eggs. Mean weight of produced eggs was 239.17 g, while individual parameters were 70.4 mg for the weight and 4.58 mm for the diameter. Originality. For the first time a study aimed at the formation of brood stocks of rainbow trout with analysis of phenotypic and productive features in the conditions of a fish farm with instable temperature and water regimes has been conducted. Practical value. The results of the performed work will allow selecting and forming a brood stock with high values of productive and reproductive features.

  11. Environmental and human health risk assessment of organic micro-pollutants occurring in a Spanish marine fish farm

    International Nuclear Information System (INIS)

    Munoz, Ivan; Martinez Bueno, Maria J.; Agueera, Ana; Fernandez-Alba, Amadeo R.

    2010-01-01

    In this work the risk posed to seawater organisms, predators and humans is assessed, as a consequence of exposure to 12 organic micro-pollutants, namely metronidazole, trimethoprim, erythromycin, simazine, flumequine, carbaryl, atrazine, diuron, terbutryn, irgarol, diphenyl sulphone (DPS) and 2-thiocyanomethylthiobenzothiazole (TCMTB). The risk assessment study is based on a 1-year monitoring study at a Spanish marine fish farm, involving passive sampling techniques. The results showed that the risk threshold for irgarol concerning seawater organisms is exceeded. On the other hand, the risk to predators and especially humans through consumption of fish is very low, due to the low bioconcentration potential of the substances assessed. - Exposure and effects of twelve organic micro-pollutants are evaluated at a Spanish fish farm.

  12. Environmental and human health risk assessment of organic micro-pollutants occurring in a Spanish marine fish farm

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Ivan, E-mail: ivanmuno@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Martinez Bueno, Maria J., E-mail: mjbueno@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Agueera, Ana, E-mail: aaguera@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Fernandez-Alba, Amadeo R., E-mail: amadeo@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain)

    2010-05-15

    In this work the risk posed to seawater organisms, predators and humans is assessed, as a consequence of exposure to 12 organic micro-pollutants, namely metronidazole, trimethoprim, erythromycin, simazine, flumequine, carbaryl, atrazine, diuron, terbutryn, irgarol, diphenyl sulphone (DPS) and 2-thiocyanomethylthiobenzothiazole (TCMTB). The risk assessment study is based on a 1-year monitoring study at a Spanish marine fish farm, involving passive sampling techniques. The results showed that the risk threshold for irgarol concerning seawater organisms is exceeded. On the other hand, the risk to predators and especially humans through consumption of fish is very low, due to the low bioconcentration potential of the substances assessed. - Exposure and effects of twelve organic micro-pollutants are evaluated at a Spanish fish farm.

  13. Occurrence of Antimicrobial Resistance in Fish-Pathogenic and Environmental Bacteria Associated with Four Danish Rainbow Trout Farms

    DEFF Research Database (Denmark)

    Schmidt, Anja S.; Bruun, Morten Sichlau; Dalsgaard, Inger

    2000-01-01

    in fish, water, and sediment samples, two major fish pathogens (88 Flavobacterium psychrophilum isolates and 134 Yersinia ruckeri isolates) and 313 motile Aeromonas isolates, representing a group of ubiquitous aquatic bacteria, were isolated from the same samples. MICs were obtained applying...... flavobacteria and aeromonads, thus indicating a substantial impact of fish farming on several groups of bacteria associated with aquacultural environments....

  14. Economic and Environmental Impacts of Improving Growth Rate and Feed Efficiency in Fish Farming Depend on Nitrogen and Density Limitation

    NARCIS (Netherlands)

    Besson, M.; Komen, H.; Vandeputte, M.; Aubin, J.; Boer, de I.J.M.; Arendonk, van J.A.M.

    2014-01-01

    The aim of fish breeding is to increase profit by producing faster growing fish with lower feed intake. However, little is known about the economic and environmental impacts of selective breeding programs for fish. We modelled a fish farm producing African catfish in a Recirculating Aquaculture

  15. Radionuclide concentrations in game and nongame fish upstream and downstream of Los Alamos National Laboratory: 1981 to 1993

    International Nuclear Information System (INIS)

    Fresquez, P.R.; Armstrong, D.R.; Salazar, J.G.

    1994-08-01

    Radionuclide concentrations were determined in game (surface-feeding) and nongame (bottom-feeding) fish collected from reservoirs upstream (Abiquiu, Heron, and El Vado) and downstream (Cochiti) of Los Alamos National Laboratory from 1981 to 1993. The average levels of 90 Sr, 137 Cs, 238 Pu, and 239 Pu in game and nongame fish collected from Cochiti reservoir were not significantly different in fish collected from reservoirs upstream of the Laboratory. Total uranium was the only radionuclide that was found to be significantly higher n both game and nongame fish from Cochiti as compared to fish from Abiquiu, Heron, and El Vado. Uranium concentrations in fish collected from Cochiti, however, significantly decreased from 1981 to 1993, and no evidence of depleted uranium was found in fish samples collected from Cochiti in 1993. Based on the average concentration of radionuclides over the year the effective (radiation) dose equivalent from consuming 46 lb of game fish and nongame fish from Cochiti reservoir after natural background has been subtracted was 0.005 and 0.009 mrem/yr, respectively. The highest dose was <0.01% of the International Commission on Radiological Protection (ICRP) permissible dose limit for protecting members of the public

  16. Determination of trace elements in tailpipe fish produced in artificial farms and from white and blue nile

    International Nuclear Information System (INIS)

    Ahmed, Zeinb Khalil Elsaim

    2017-01-01

    In this study, an analytical protocol of x-ray fluorescence spectroscopy was used to determine the concentration of 13 trace elements, potassium (K), antimony (Sb), iron (Fe), copper (Cu), zinc (Zn), lead (Pb), bromine (Br), rubidium (Rb), strontium (Sr), mercury (Hg), chromium (Cu), manjense (Mn), and calcium (Ca), in tilapa fish. A total of 70 samples covering 35 fish samples collected from different states includes Eldamazine for blue nile samples and the Mawrada market for the white nile samples and 5 artificial fish farms samples were collected from Om badda in Omdurman and Bahry state for three farms Alsamraband Aldorshab and from Alshagra state in Khartoum, during may to June 2016. The trace elements detected in all samples, and the concentration in part million (ppm). The concentrations of trace elements followed the sequence of, K, Ca, Fe, Zn, Cu, Sr, Rb, Pb, but Cr, Hg and Ni were observed in one fish fram (farm A). The analysis included two tissues (flesh and gills), because most people in Sudan consume the flesh and gills, specially in the small fishes, consider as good indicators for the trace elements, and toxic compounds in general. The analysis indicated that the white nile fishes have higher l eves of most of the trace elements compared to the blue nile, e.g. Fe (560±186) in the white nile, whereas in the blue nile, (188±63). On the other hand , the artificial tilapia farms showed significant variations in the trace elements concentrations. The analysis revealed that a higher concentrations of most of the trace elements in gill tissues than flesh, e.g. Fe (1673±1453) in the flesh, and (9768±1175) in the gills. These results indicated that the gill accumulated higher levels of heavy metals than other organs, because they acted as a depot tissue. In addition, the post hoc test was performed following (Dunnett tests), using the blue nile group as a control group, since it has the lowest trace elements concentrations, among the river nile fishes in

  17. Phytoremediation Capabilities of Spirodela polyrhiza and Salvinia molesta in Fish Farm Wastewater: A Preliminary Study

    Science.gov (United States)

    Ng, Y. S.; Samsudin, N. I. S.; Chan, D. J. C.

    2017-06-01

    Fish farm wastewater needs to be treated as it contains considerably high loading of suspended solids and dissolved nutrients from accumulation of by-products e.g. fish excretions and uneaten feed. In this study, macrophytes, namely Spirodela polyrhiza and Salvinia molesta were examined for their phytoremediation efficiency in treating fish farm wastewater in a raceway pond rig. It was carried out indoor for 14 days under controlled environment. Water samples was collected once every 2 days for analysis of NO3 -- N, PO4 3-, NH3-N, COD, turbidity, MLVSS and pH. The results showed that there was decrement of phosphate in fish farm wastewater using either S. polyrhiza or S. molesta. Interestingly, S. polyrhiza was found to be more efficient in phosphate uptake as it removed 72% phosphate at day 4 and up to 95% in the end of the experiment whereas 72% phosphate removal was only achieved by S. molesta at day 10. Similar ammonia decrement was observed for both plants and most of the ammonia were not detected in the wastewater by day 10 for S. polyrhiza, while by day 8 for S. molesta. Nitrate showed increment for both plants which could be due to nitrification. Both plants achieved highest COD removal on day 12, whereby 68% for S. polyrhiza and 63% for S. molesta. They were able to reduce turbidity and total suspended solids (TSS) to very low level and significantly increase clarity of wastewater. S. polyrhiza reduced up to 96% of initial turbidity value and 86% of TSS. 82% reduction of initial turbidity and 79% TSS decrement were observed for S. molesta. pH fluctuations were minimum for both plants, with a range between 7.62 to 7.77. Both plants demonstrated biomass increment for fresh weight in which 84% for S. polyrhiza while 85% for S. molesta. This study proved that the macrophytes were able to treat fish farm wastewater by significantly removing phosphate, ammonia, turbidity and TSS. It aids in minimizing pollutants released to receiving waters and producing biomass

  18. Improving the productivity of imported dairy cattle on small-holder farms in Morocco through supplementation with fish silage blocks

    International Nuclear Information System (INIS)

    Guerouali, A.

    1999-01-01

    The present study was designed to identify problems that lower the productivity of imported dairy cattle in Morocco. For this purpose, a comprehensive survey was carried out on 8 small-holder farms over a period of two years. Analysis of the data collected indicated that in most of the herds reproductive performance was adequate (calving intervals ranging from 338 ± 11 to 420 ± 31 and services to conception ranging from 1.14 ± 0.13 to 1.91 ± 0.3), but the animals had difficulty in meeting the nutrient requirements for milk production. Although some farmers provided supplements to their animals they were either expensive or not available at the required time. One possible way of alleviating the problem was the introduction of a fish by-product into the dairy cattle ration. Two experiments were conducted, one at the Institute experimental farm and the other at a private farm selected for the survey. In both experiments, fish silage blocks were incorporated into the ration of dairy cattle in replacement of an equal amount of the most commonly used supplements. The introduction of fish silage blocks in the ration did not affect their intake or body condition. In addition, the yield and quality of the milk were maintained. This substitution allowed the farmer to utilize by-products from the fish industry which are readily available and less costly than most conventional supplementary feeds. It is concluded, that the proposed utilization of fish silage blocks will reduce the production costs and improve the economic efficiency of the small-holder farms. (author)

  19. Principle and design of hatch operation system for fish migrating upstream-downstream of the discharge sill

    Directory of Open Access Journals (Sweden)

    Răzvan G.Voicu

    2016-09-01

    Full Text Available To improve fish migration and restore local lotic ecosystems, it is necessary to consider the various current hydro-construction methods. There have been partial successes in systems that improve fish passage over various obstacles but new approaches that present more efficient solutions and international collaboration among specialists are required. This article deals with European themes of great interest; issues related to interruption of longitudinal connectivity in heavily modified water courses, and improving the ecological status of damaged lotic systems, with the goal of achieving the environmental objectives set forth by the Water Framework Directive 2000/60/EC (WFD and the national legislative framework regarding water policy (which reflects the European directives Water Law no. 107, with subsequent amendments, NT No. / 2006 OM 1163/2007, and discusses the obligation to ensure that construction works protect fish migration to maintain ecological balance in the reservoirs. It is possible to use this system in almost any fish-bearing stream, both upstream and downstream of maximum circulation, which makes the system an excellent solution for assisting and improving migration.

  20. Mesoscale changes in the water column in response to fish farming zones in three coastal areas in the Eastern Mediterranean Sea

    Science.gov (United States)

    Pitta, P.; Apostolaki, E. T.; Giannoulaki, M.; Karakassis, I.

    2005-11-01

    The hypothesis that the presence of fish farming zones affects the water quality and plankton communities at large spatial scales was investigated through sampling carried out in three regions of the Aegean Sea during May and September. In each region, two sub-areas were sampled: one with fish farming zones (within 2-3 nm) and one without fish farms ('reference site', more than 20 nm). Replicated water samples at different depths were taken in each sub-area for each of the investigated regions. Samples were analysed for nutrients, chlorophyll a, phaeopigments, POC and PON as well as for heterotrophic bacteria, cyanobacteria, flagellates and ciliates. Statistically significant changes in some nutrient species were found during September, which is in the period of maximal supply of feed to caged fish and nutrient loss to a highly stratified oligotrophic environment. Most of the significant changes of nutrients as well as chlorophyll a or PON were found at the deepest layer of the water column below the thermocline, indicating that it is related to the remineralization of benthic organic material. The data support previously published results in this area indicating that there is a rapid transfer of nutrients up the food web. This study also showed the need for studying the effects of fish farms on water quality at larger spatial scales.

  1. PHYTOPLANKTON COMPOSITION IN FISH FARMS ALONG THE EASTERN ADRIATIC COAST

    Directory of Open Access Journals (Sweden)

    Marija Tomec

    2006-10-01

    Full Text Available Investigations of net phytoplankton composition were performed at three fish farms situated at the northern, middle and southern part of the eastern Adriatic Sea coast, respectively. In the northern part investigations were conducted in the Limski kanal, in the middle part at the Ugljan island and in the southern part in the place Drače on the Pelješac peninsula (Figure 1. At all three localities fish culture included mostly two species: gilthead sea bream (Sparus aurata and sea bass (Dicentrarchus labrax. Beside some physico–chemical parameters (sea water temperature, salinity special attention was placed on the examination of qualitative net phytoplankton composition, which was conducted in the period of May and November 2004 and May and October 2005. Samples were collected at the depths of 0. 5 and 4 meters. According to the physico–chemical parameters, sea water temperature was influenced by the temperature of the environment. Qualitative net phytoplankton composition consisted of 153 microphytic species belonging to the systematic compartments of Cyanobacteria, Chrysophyta and Dinophyta (Table 1. The most numerous algal group were diatoms or Bacillarophyceae (84 species or 55% with relative frequencies of species from 1 to 7. Taxonomic composition of diatoms showed the community Chaetoceros–Rhizosolenia (Proboscia as the dominant one. The second numerically most dominant compartment were Dinophyta (62 species or 401% with dominant the species of the genera Ceratium and Protoperidinium. Relative frequencies of species was ranging from 1 to 7 (mass presence of specimens in the water column. From Cyanobacteria (4 species or 3%, only filamentous algae were determined, with individual presence in net phytoplankton composition. Qualitative net phytoplankton composition suggests the similarity of species composition in the water column at all investigated fish farms. From the obtained characteristics of net phytoplankton composition

  2. Fish farming of native species in Colombia: current situation and perspectives

    DEFF Research Database (Denmark)

    Cruz-Casallas, P. E.; Medina-Robles, V. M.; Velasco-Santamaria, Y. M.

    2011-01-01

    . The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico......In Colombia and the rest of the world, the decrease in capture fisheries production has turned the aquaculture into an alternative source of protein for the populations food security as well as an important productive activity, generating employment and income for the rural communities...... Prochilodus magdalenae (Steindachner), carp Cyprinus carpio (Linnaeus) and yamu Brycon amazonicus (Spix & Agassiz). From the three main fish species, cachama blanca is the only native species, which has shown excellent performance in pond farming due to its rusticity, omnivorous habits, docility, meat quality...

  3. Influence of tubificid worms on nutrient fluxes across water-sediment interface in fish farm settling ponds

    Directory of Open Access Journals (Sweden)

    Puigagut J.

    2014-04-01

    Full Text Available The influence of tubificid worms on nutrient translocation from water to fish farm sediments accumulating in settling ponds was addressed under laboratory conditions. Small microcosms of 0.5 L were filled up with 35 g of sludge from a fish farm settling pond and 0.15 L of filtered settling pond water. The experimental set up consisted of one control line (no worms added, a second experimental line with 1 mg of tubificid worms·g-1 fresh sediment (550 individuals·m-2 and a third experimental line with 40 mg of tubificid worms·g-1 fresh sediment (22 000 individuals·m-2. Nutrients translocation was determined by monitoring overlaying water concentration of ammonia, nitrate and phosphate for ten days. Results showed that abundances of 550 individuals·m-2 had no significant influence on the fluxes of nutrients here considered. However, the influence of higher abundances of tubificids (22 000 individuals·m-2 was of significant extent on the translocation of nitrate and phosphate. Accordingly, bioturbation of tubificids caused 55% lower nitrate uptake by the sediment when compared to control conditions. Phosphorus released by the sediments of the control condition was ca. 90% higher than that recorded under abundances of tubificids (22 000 individuals·m-2. Results obtained allowed us to estimate that fish farm settling ponds highly colonized by tubificid worms (22 000 individuals·m-2 may contribute to decrease phosphorus discharge (in terms of soluble phosphorus in ca. 5 g of P·ton-1 of fish produced.

  4. Fillet proximate composition, lipid quality, yields, and organoleptic quality of Mediterranean-farmed marine fish: A review with emphasis on new species.

    Science.gov (United States)

    Grigorakis, Kriton

    2017-09-22

    Species diversification in Mediterranean mariculture involves various important fish that contribute to the diet of many human populations. These include meagres (Sciaenidae), flatfishes, mullets, and various sparids. Their quality aspects (yields, fillet proximate composition, and lipid quality) are discussed in this review. Their filleting yield is mostly 40-45%. The viscerosomatic index ranges from 1.5% to 14%, depending on species. Low muscle fat contents of flatfishes and meagres differentiate them from the rest of the farmed species. Farmed fish contain high n-3 polyunsaturates fatty acids (PUFA; 12.3-36.3% vs. 5.48-37.2% in the wild) and have higher muscle fat and n-6 PUFA contents (mainly 18:2 n-6) than their wild counterparts. The aquaculture management, diet, and season can affect fillet composition and fatty acids, while season (i.e. food availability and maturation) largely affects lipid quality in wild fish. Data on the sensory quality of Mediterranean-farmed species are mainly limited to whether specific management differentiates the sensory quality; thus, further development of tools for sensory analysis is required. Observations on the quality features in farmed Mediterranean fish indicate that species diversification can also provide product diversification based on different commercial weights and fillet quality specifications.

  5. Stable isotope evidence for the environmental impact of a land-based fish farm in the western Mediterranean

    International Nuclear Information System (INIS)

    Vizzini, Salvatrice; Mazzola, Antonio

    2004-01-01

    Isotopic examination (δ 13 C and δ 15 N) of organic matter sources and consumers was used to assess the impact and trace the dispersal of wastewater from a land-based fish farm in western Mediterranean. The results provide evidence of the non-negligible effect of aquaculture facilities on the natural stable isotopic composition of organisms. Aquaculture waste entered the food web, altering the natural isotopic composition of organic matter sources at the base and the upper trophic levels. Nitrogen-rich fish waste mainly affected δ 15 N values, while δ 13 C showed less alteration. Waste seemed to disperse widely enough to affect the isotopic composition at the study site about 500 m from the outfall, while sites at 1 and 2 km from the outfall showed values that were similar to each other and different from those of the impacted site. The impact was detected at different ecosystem levels, although primary producers were more affected by fish farm waste taking up aquaculture-derived nutrients

  6. Animal welfare in brown trout farming: hematological results

    Directory of Open Access Journals (Sweden)

    G. Forneris

    2010-01-01

    Full Text Available The effect of stress resulting from fish farming has received considerable attention in this last period and fish welfare in aquaculture is a relevant topic, very important for the future of aquaculture (Watson et al., 2004; Klinger et al., 1996; Peres et al., 2004; Ron et al., 1995;Wagner et al., 1995;Watson et al., 1998. Brown trout farming is less developed then rainbow trout farming, but this kind of fish farming is increasing, mainly for fish conservation and restocking aquaculture.

  7. Environmental health impacts of feeding crops to farmed fish.

    Science.gov (United States)

    Fry, Jillian P; Love, David C; MacDonald, Graham K; West, Paul C; Engstrom, Peder M; Nachman, Keeve E; Lawrence, Robert S

    2016-05-01

    Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. Traditionally, aquaculture feed has contained high levels of wild fish, which is unsustainable for ocean ecosystems as demand grows. The aquaculture industry is shifting to crop-based feed ingredients, such as soy, to replace wild fish as a feed source and allow for continued industry growth. This shift fundamentally links seafood production to terrestrial agriculture, and multidisciplinary research is needed to understand the ecological and environmental health implications. We provide basic estimates of the agricultural resource use associated with producing the top five crops used in commercial aquaculture feed. Aquaculture's environmental footprint may now include nutrient and pesticide runoff from industrial crop production, and depending on where and how feed crops are produced, could be indirectly linked to associated negative health outcomes. We summarize key environmental health research on health effects associated with exposure to air, water, and soil contaminated by industrial crop production. Our review also finds that changes in the nutritional content of farmed seafood products due to altered feed composition could impact human nutrition. Based on our literature reviews and estimates of resource use, we present a conceptual framework describing the potential links between increasing use of crop-based ingredients in aquaculture and human health. Additional data and geographic sourcing information for crop-based ingredients are needed to fully assess the environmental health implications of this trend. This is especially critical in the context of a food system that is using both aquatic and terrestrial resources at unsustainable rates. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Long-term effects of an offshore wind farm in the North Sea on fish communities

    DEFF Research Database (Denmark)

    Stenberg, Claus; Støttrup, Josianne; Deurs, Mikael van

    2015-01-01

    Long-term effects of the Horns Rev 1 offshore wind farm (OWF) on fish abundance, diversity and spatial distribution were studied. This OWF is situated on the Horns Reef sand bank in the North Sea. Surveys were conducted in September 2001, before the OWF was established in 2002, and again...... in September 2009, 7 yr post-establishment. The sampling surveys used a multi-mesh-size gillnet. The 3 most abundant species in the surveys were whiting Merlangius merlangus, dab Limanda limanda and sandeels Ammodytidae spp. Overall fish abundance increased slightly in the area where the OWF was established...... but declined in the control area 6 km away. None of the key fish species or functional fish groups showed signs of negative long-term effects due to the OWF. Whiting and the fish group associated with rocky habitats showed different distributions relative to the distance to the artificial reef structures...

  9. Prevalence of antibiotic resistance genes in the bacterial flora of integrated fish farming environments of Pakistan and Tanzania.

    Science.gov (United States)

    Shah, Syed Q A; Colquhoun, Duncan J; Nikuli, Hamisi L; Sørum, Henning

    2012-08-21

    The use of a wide variety of antimicrobials in human and veterinary medicine, including aquaculture, has led to the emergence of antibiotic resistant pathogens. In the present study, bacteria from water, sediments, and fish were collected from fish farms in Pakistan and Tanzania with no recorded history of antibiotic use. The isolates were screened for the presence of resistance genes against various antimicrobials used in aquaculture and animal husbandry. Resistant isolates selected by disk diffusion and genotyped by Southern hybridization were further screened by polymerase chain reaction (PCR) and amplicon sequencing. The prominent resistance genes identified encoded tetracycline [tetA(A) and tetA(G)], trimethoprim [dfrA1, dfrA5, dfrA7, dfrA12, and dfrA15], amoxicillin [bla(TEM)], streptomycin [strA-strB], chloramphenicol [cat-1], and erythromycin resistance [mefA]. The int1 gene was found in more than 30% of the bacterial isolates in association with gene cassettes. MAR indices ranged from 0.2 to 1. The bla(NDM-1) gene was not identified in ertapenem resistant isolates. It is hypothesized that integrated fish farming practices utilizing domestic farm and poultry waste along with antibiotic residues from animal husbandry may have contributed to a pool of resistance genes in the aquaculture systems studied.

  10. First testing of an AUV mission planning and guidance system for water quality monitoring and fish behavior observation in net cage fish farming

    Directory of Open Access Journals (Sweden)

    D. Karimanzira

    2014-12-01

    Full Text Available Recently, underwater vehicles have become low cost, reliable and affordable platforms for performing various underwater tasks. While many aquaculture systems are closed with no harmful output, open net cage fish farms and land-based fish farms can discharge significant amounts of wastewater containing nutrients, chemicals, and pharmaceuticals that impact on the surrounding environment. Although aquaculture development has often occurred outside a regulatory framework, government oversight is increasingly common at both the seafood quality control level, and at baseline initiatives addressing the basic problem of pollution generated by culture operations, e.g. the European marine and maritime directives. This requires regular, sustainable and cost-effective monitoring of the water quality. Such monitoring needs devices to detect the water quality in a large sea area at different depths in real time. This paper presents a concept for a guidance system for a carrier (an autonomous underwater vehicle of such devices for the automated detection and analysis of water quality parameters.

  11. Can energy willow (Salix sp.) remediate cadmium- and nickel-contaminated fish farm sludge?

    DEFF Research Database (Denmark)

    Pedersen, Marianne Bruus

    it meets the criteria. Phytoremediation by willow may combine accumulation of cadmium and nickel from the sludge with the production of an energy crop. The ability of eight selected willow clones to take up and tolerate cadmium and nickel was studied in pots under outdoor conditions. Fish farm sludge...

  12. Effects of nutrient enrichment derived from fish farming activities on macroinvertebrate assemblages in a subtropical region of Hong Kong.

    Science.gov (United States)

    Gao, Qin-Feng; Cheung, Kwok-Leung; Cheung, Siu-Gin; Shin, Paul K S

    2005-01-01

    To study the correlation between nutrient enrichment derived from fish farming activities and changes in macrobenthic assemblages, a one-year field study was conducted in Kau Sai Bay marine fish culture zone of Hong Kong. Bimonthly sediment samples were collected at six stations: two at the fish cages, two near the boundary of the fish culture area, and two reference sites further away from the culture area. Sediment physico-chemical characteristics in terms of silt/clay fraction, moisture content, total organic carbon (TOC), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) were analyzed. The macrobenthos (>0.5 mm) present in the sediment were sorted, identified and enumerated. On average, TOC, TKN and TP levels at the fish cage stations were 82.8%, 128.5% and 1315.7% higher than those at the reference stations, respectively. As a result, the N:P molar ratio was greatly reduced from 8.75 at the reference stations to 1.83 at the fish cage stations. Univariate and multivariate analyses revealed that diversity of macrofauna was significantly reduced and community structure differed at the fish cage stations relative to the reference sites. The intermediary stations near the fish culture area showed a transitional state of disturbance. Faunal diversity was negatively correlated with nutrient level, reflecting the adverse impacts of nutrient enrichment derived from fish farming activities on the benthic assemblages. Whilst in subtropical Asia-Pacific trash fish is the major feed for fish culture resulting in a higher nutrient loading and nutrient ratio accumulated in the sediment beneath the fish rafts, the effects of nutrient enrichment on macrobenthic assemblages are comparable to that in temperate waters owing to relatively high sediment metabolism rate and smaller fish culture scale in Hong Kong.

  13. Particulate waste outflow from fish-farming cages. How much is uneaten feed?

    Science.gov (United States)

    Ballester-Moltó, M; Sanchez-Jerez, P; Cerezo-Valverde, J; Aguado-Giménez, F

    2017-06-15

    Particulate wastes drive benthic organic enrichment from cage fish farming. Differentiation between faeces and uneaten feed estimates at cage level are of great value to both economize the feeding process and reduce waste. This study estimates the particulate waste outflowing cages at different depths and orientations, and the wasted feed component by combining in situ measurements and modelling. Particulate matter flux (PMF) was greater vertically through the cage bottoms (60.89%), but lateral outflow was also substantial (39.11%). PMF occurs all around the cages, and the influence of the mainstream current was low. Wasted feed was greatly variable, reaching high values (about 50% of supplied feed. The self-application of feed wastage monitoring and estimates by fish farmers is recommended to improve sustainability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The bottlenose dolphin Tursiops truncatus foraging around a fish farm: Effects of prey abundance on dolphins’ behavior

    Directory of Open Access Journals (Sweden)

    Bruno Díaz LÓPEZ

    2009-08-01

    Full Text Available The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied. The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond, individually and as groups, to the relative abundance of prey around a fish farm. Detailed views of dolphins’ behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data. A total of 2150 dive intervals were analyzed, corresponding to 342 focal samples, lasting over 34 hours. Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds. This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area. This study’s results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding, dolphins did not modify dive duration. Additionally, underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities. Thus, bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey. When top predators display behavioral responses to activities not directed at them, the task of studying all possible effects of human activities can become even more challenging [Current Zoology 55(4: 243–248, 2009].

  15. Analysis of Goat Farming on Integrated Farming System in Banyumas

    OpenAIRE

    Hidayat, NN

    2007-01-01

    The objective of this research were : 1) to find out the income generated from goat farming and its contribution to farmer income in several farming combination, 2) to find out the economic efficiency in goat farming with paddy and fish production, 3) to determine factors affecting level of production and income in different farming system, partially and aggregately, and 4) to determine the best combination of farming which generated maximum income. Household farmer survey method was performe...

  16. Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus)

    NARCIS (Netherlands)

    Besson, M.; Komen, H.; Aubin, J.; Boer, de I.J.M.; Poelman, M.; Quillet, E.; Vancoillie, C.; Vandeputte, M.; Arendonk, van J.A.M.

    2014-01-01

    In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal

  17. Fish ladders: safe fish passage or hotspot for predation?

    Directory of Open Access Journals (Sweden)

    Angelo Antonio Agostinho

    Full Text Available Fish ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent of large predatory fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir using gillnets, cast nets and counts or visual observations. The captured fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-fish vertebrates. The main predatory fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the fish corridor into a hotspot for

  18. TECHNOLOGY CHARACTERIZATION OF THE FISH FARM OF THE MUNICIPALITY OF CAPITÃO POÇO, PARÁ, BRAZIL

    Directory of Open Access Journals (Sweden)

    Tiago Pereira Brito

    2017-07-01

    Full Text Available The present study describes the technological aspects of fish farming developed on the Capitão Poço in northeastern state of Pará. The data were collected through 17 semi-structured interviews in aquaculture properties in the region.The farmer was legally responsible for most property. The property's operating time ranged from 3 to 20 years and the time of experience in aquaculture activity from 10 months to 20 years (mean 5.4 ± 2.9 years. Aquaculture represented a secondary activity is for subsistence or to supplement the family income. The properties had a total area ranging from 0.5 to 750 hectares (average 124.9 ± 150.0 ha, with water area between 0.00165 and 2.16 ha (average 0.4944 ± 0.5694 ha. The semi-intensive production system was predominant (88.2%, however, the intensive system keeper tanks was also recorded (11.8%, and recorded both monocultures (70.6% as policultives (29, 4%, with cultive of Oreochromis niloticus, Colossoma macropomum, Leporinus friderici and two species hybrid. The management with regard to the analysis of water quality of farming, food supply and evaluation of growth performance, although carried out were not satisfactory, requiring greater technical training to producers. Keywords Amazon; aquaculture; farmer fish; fish; cultivation system.

  19. Occurrence of antibiotic resistance and characterization of resistant genes and integrons in Enterobacteriaceae isolated from integrated fish farms south China

    Science.gov (United States)

    Su, Hao-Chang; Ying, Guang-Guo; Tao, Ran; Zhang, Rui-Quan; Fogarty, Lisa R.; Kolpin, Dana W.

    2011-01-01

    Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture.

  20. Fish parasites

    DEFF Research Database (Denmark)

    This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems......This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems...

  1. Simulation of wake effects between two wind farms

    International Nuclear Information System (INIS)

    Hansen, K S; Réthoré, P-E; Peña, A; Ott, S; Van der Laan, M P; Volker, P; Palma, J; Hevia, B G; Prospathopoulos, J; Schepers, G; Palomares, A

    2015-01-01

    SCADA data, recorded on the downstream wind farm, has been used to identify flow cases with visible clustering effects. The inflow condition is derived from a partly undisturbed wind turbine, due to lack of mast measurements. The SCADA data analysis concludes that centre of the deficit for the downstream wind farm with disturbed inflow has a distinct visible maximum deficit zone located only 5-10D downstream from the entrance. This zone, representing 20-30% speed reduction, increases and moves downstream for increasing cluster effect and is not visible outside a flow sector of 20-30°. The eight flow models represented in this benchmark include both RANS models, mesoscale models and engineering models. The flow cases, identified according to the wind speed level and inflow sector, have been simulated and validated with the SCADA results. The model validation concludes that all models more or less are able to predict the location and size of the deficit zone inside the downwind wind farm. (paper)

  2. On-farm feed: the potential for improving profitability in aquaculture

    OpenAIRE

    Ibiyo, L.M.O.; Olowosegun, T.

    2005-01-01

    The urge to develop a standard practical diet for farmed fish in Nigeria has been on the increase since the last decade. Since ages diets has ever represent the largest single cost item of most fish farm operations. This is the reason why careful selection of feed ingredients for use in aqafeed plays a vital role in the resultant nutritional and economic success of farmed fish. In an attempt to meet the objectives of culturing fish two main sources of fish feed have been identified for meetin...

  3. SILVER CRUCIAN OR CHITON AND DAMAGES IT SAUSSES BY ITS PRESENCE ON FISH FARMS

    Directory of Open Access Journals (Sweden)

    Ljubomir Kajgana

    1996-06-01

    Full Text Available By its presence, silver crucian carp or chiton (Carassius auratus gibelio Bloch. makes lot of damage on fish-farms. By its nutrition way, the chiton competes with carp, thus reducing its growths and increasing the nutritive coefficient what is unjustified both economically and technologically. The diclinous and hermaphroditic way of procreation influences the spread of this species. After the dissection of an chiton exemplar of 10-12 dag in October 1995 in Našice “Ribnjak 1905” it was stated that it had 23% of male fish. Spawn was in the IV. stage of sex maturity according to Kiseljević. The ways of chiton coming and going to particular pounds as well as measures to control it are analyzed in the text. It is recommended to turn full attention to the filling and re-filling of pounds, prevent the coming of wild fish and fill canals and pounds thoroughly.

  4. CONDITIONS OF FISH FARMING IN NATURA 2000 AREAS, BASED ON THE EXAMPLE OF THE CATCHMENT OF BARYCZ

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    Katarzyna Tokarczyk-Dorociak

    2016-07-01

    Full Text Available One of the factors that contributed to the construction of approx.77 km2 offish ponds in the catchment of Barycz starting from the 13th century, which in turn transformed the woods into a mosaic of waters, forests and arable land, were the advantageous physiographic conditions. Fish farming operations conducted in this area led to the creation of a cultural landscape characterised by unique natural values, similar to the natural landscape.Approx.240 species of birds are observed here, of which 170 are nesting species. Due to its natural values, this area has been subject to natural reserve protection as part of the Landscape Park "Dolina Baryczy" (the Barycz Valley. It was entered in the "Living Lakes" list and it is protected under the Ramsar Convention as well as under the European nature protection network Natura 2000.The established forms of nature protection mean the introduction of a certain binding regime, pursuant to which the economic activity conducted in protected areas must take into account the prohibitions and orders introduced by documents that establish the said forms of protection. Additionally, there is a legal requirement to create a protection plan or conservation plan that constitutes a basis for the realisation of conservation-related objectives. A commercial company Stawy Milickie S.A. (public limited company operates in the area of this largest fish pond complex in Poland. The scope of its operations includes more than just the breeding and sale of freshwater fish (6500 ha of ponds but also environmental protection, environmental education and the development of tourism as well as stimulating the development and professional activation of local communities basing on the natural resources that exist in the catchment of Barycz. This study presents the conditions related to fish farming operations conducted in this area. Conducting an extensive management (i.e. often uneconomical from the economic point of view is a

  5. An outbreak of myxozoan parasites in farmed freshwater fish Colossoma macropomum (Cuvier, 1818 (Characidae, Serrasalminae in the Amazon region, Brazil

    Directory of Open Access Journals (Sweden)

    Marcela Videira

    2016-05-01

    Full Text Available The tambaqui (Colossoma macropomum is a native fish species that is farmed most frequently and in the largest quantities throughout Brazil. The high production of this species from fish farms has contributed to the occurrence of emerging parasites, which may compromise fish health and productivity. In a batch of 2500 tambaqui fry acquired for experimental farming procedures in Brazil, a mortality rate of 80% was observed, with the fish swimming erratically and gasping for air at the water surface. From among the specimens that were still alive, 60 individuals were selected at random. Organs or fragments of organs containing lesions and/or cysts were examined under an optical microscope to investigate for the presence of parasitic spores. Of the 60 specimens of tambaqui analyzed, 83.3% were found to be infected in different organs, such as the gills, liver, and gallbladder with myxosporidian species belonging to four genera, namely, Myxobolus, Ellipsomyxa, Henneguya and Thelohanellus. The parasite with the greatest prevalence was Myxobolus sp., located in the gills (70%, followed by Henneguya sp. in the gills region (68.3%, Myxobolus sp. in the liver (63.3%, Thelohanellus sp. in the liver (58.3%, and Ellipsomyxa in the gallbladder (50%. This is the first report of parasitic infection caused by the genera Ellipsomyxa and Thelohanellus in C. macropomum. The present study reported the second incidence of the occurrence of the genus Thelohanellus in South America. This study suggested that the mortality among C. macropomum specimens was caused by the outbreak of myxosporidians. Keywords: Amazon, Tambaqui, Parasite, Myxozoa, Myxosporidians

  6. Scrapie infectivity is quickly cleared in tissues of orally-infected farmed fish

    Directory of Open Access Journals (Sweden)

    Faoro Franco

    2006-06-01

    Full Text Available Abstract Background Scrapie and bovine spongiform encephalopathy (BSE belongs to the group of animal transmissible spongiform encephalopathy (TSE. BSE epidemic in the UK and elsewhere in Europe has been linked to the use of bovine meat and bone meals (MBM in the feeding of cattle. There is concern that pigs, poultry and fish bred for human consumption and fed with infected MBM would eventually develop BSE or carry residual infectivity without disease. Although there has been no evidence of infection in these species, experimental data on the susceptibility to the BSE agent of farm animals other than sheep and cow are limited only to pigs and domestic chicken. In the framework of a EU-granted project we have challenged two species of fish largely used in human food consumption, rainbow trout (Oncorhynchus mykiss and turbot (Scophthalmus maximus, with a mouse-adapted TSE strain (scrapie 139A, to assess the risk related to oral consumption of TSE contaminated food. In trout, we also checked the "in vitro" ability of the pathological isoform of the mouse prion protein (PrPSc to cross the intestinal epithelium when added to the mucosal side of everted intestine. Results Fish challenged with a large amount of scrapie mouse brain homogenate by either oral or parenteral routes, showed the ability to clear the majority of infectivity load. None of the fish tissues taken at different time points after oral or parenteral inoculation was able to provoke scrapie disease after intracerebral inoculation in recipient mice. However, a few recipient mice were positive for PrPSc and spongiform lesions in the brain. We also showed a specific binding of PrPSc to the mucosal side of fish intestine in the absence of an active uptake of the prion protein through the intestinal wall. Conclusion These results indicate that scrapie 139A, and possibly BSE, is quickly removed from fish tissues despite evidence of a prion like protein in fish and of a specific binding of Pr

  7. MORPHOMETRIC CHARACTERISTICS OF THE REPLACEMENT-BROOD STOCK OF RAINBOW TROUT (ONCORHYNCHUS MYKISS (WALBAUM, 1792 REARED IN THE CONDITIONS OF THE INDUSTRIAL FISH FARM "SLOBODA-BANYLIV”

    Directory of Open Access Journals (Sweden)

    P. Mendrishora

    2017-09-01

    Full Text Available Purpose. To analyze the results of morphometric measurements and dates of aquaculture-biological characteristics of the young-of-the-year and age-1+ rainbow trout reared under industrial technology at instable conditions of the fish farm “Sloboda-Banyliv”. Methodology. The study has been performed at the industrial fish farm “Sloboda-Banyliv”, Chernivtsi region. The materials for the study were young-of-the-year and age-1+ rainbow trout obtained from the eggs of autumn-spawning form rainbow trout. The young-of-the-year were reared in a 216 m2 tank with stocking density of 255 ind./m2, age-1+ fish were reared in 108 m2 tank with a stocking density of 33 ind./m2 according to generally accepted methods in trout culture. Morphometric measurements of fish were performed according to I.F. Pravdin. Statistical processing of data was carried out in Microsoft Office Excel (2003. The analysis of values was done in the system of absolute values. The analyzed criteria of the measured parameters were their mean values and standard errors (M±m, deviation (σ, variability coefficient (Cv. Fish were fed with the artificial feed with high protein content manufactured by “Biomar” (Denmark. Findings. The studies on rainbow trout rearing under industrial conditions showed that fish body proportions did not change with age, however, the length of their fins decreased. The slenderness coefficient in age-1+ fish decreased insignificantly that is typical with increasing body depth. Despite instable rearing conditions, both young-of-the-year and age-1+ fish were characterized by moderate growth rate and high feed-conversion efficiency. Originality. For the first time, in conditions of Ukraine, a study on the formation of rainbow trout brood stocks in a fish farm with instable rearing conditions was performed with the use of the analysis of phenotypical and productive features. Practical value. The results of the performed work will provide an opportunity to

  8. Appearance traits in fish farming: progress from classical genetics to genomics, providing insight into current and potential genetic improvement

    Directory of Open Access Journals (Sweden)

    Nelson eColihueque

    2014-08-01

    Full Text Available Appearance traits in fish, those external body characteristics that influence consumer acceptance at point of sale, have come to the forefront of commercial fish farming, as culture profitability is closely linked to management of these traits. Appearance traits comprise mainly body shape and skin pigmentation. Analysis of the genetic basis of these traits in different fish reveals significant genetic variation within populations, indicating potential for their genetic improvement. Work into ascertaining the minor or major genes underlying appearance traits for commercial fish is emerging, with substantial progress in model fish in terms of identifying genes that control body shape and skin colors. In this review, we describe research progress to date, especially with regard to commercial fish, and discuss genomic findings in model fish in order to better address the genetic basis of the traits. Given that appearance traits are important in commercial fish, the genomic information related to this issue promises to accelerate the selection process in coming years.

  9. Appearance traits in fish farming: progress from classical genetics to genomics, providing insight into current and potential genetic improvement

    Science.gov (United States)

    Colihueque, Nelson; Araneda, Cristian

    2014-01-01

    Appearance traits in fish, those external body characteristics that influence consumer acceptance at point of sale, have come to the forefront of commercial fish farming, as culture profitability is closely linked to management of these traits. Appearance traits comprise mainly body shape and skin pigmentation. Analysis of the genetic basis of these traits in different fish reveals significant genetic variation within populations, indicating potential for their genetic improvement. Work into ascertaining the minor or major genes underlying appearance traits for commercial fish is emerging, with substantial progress in model fish in terms of identifying genes that control body shape and skin colors. In this review, we describe research progress to date, especially with regard to commercial fish, and discuss genomic findings in model fish in order to better address the genetic basis of the traits. Given that appearance traits are important in commercial fish, the genomic information related to this issue promises to accelerate the selection process in coming years. PMID:25140172

  10. Influence of depth, time and human activity on detection rate of acoustic tags: a case study on two fish farms.

    Science.gov (United States)

    Otterå, H; Skilbrei, O T

    2016-03-01

    The detection rates of stationary acoustic transmitters deployed at three depths on two Atlantic salmon Salmo salar cage farms for c. 2 months were investigated. Deployment depth, time of day, day of the year and specific incidences at the farm substantially affected the rate of signal detection by the receiver. © 2016 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

  11. The role of farmed fish in the diets of the resource-poor in Egypt.

    OpenAIRE

    El Mahdi, A.; Krstic, J.; Abdallah, A.; Abdullah, H.; Kantor, P.; Valpiani, N.

    2015-01-01

    The Egyptian aquaculture industry provides more than 100,000 full-time or part-time jobs and produces the country’s least-expensive farmed animal protein. Thus, aquaculture plays an important role in both sustaining livelihoods and improving the diet quality and nutritional health of Egyptians, including a significant proportion of the 25.5% who are resource-poor. Recognizing this dual role, WorldFish has promoted sustainable growth in Egyptian aquaculture for more than 20 years. Through its ...

  12. Ecological responses of epilithic diatoms and aquatic macrophytes to fish farm pollution in a Spanish river

    Directory of Open Access Journals (Sweden)

    Camargo, Julio A.

    2007-12-01

    Full Text Available We examined the ecological responses of epilithic diatoms and aquatic macrophytes to organic pollution and nutrient enrichment caused by a trout farm effluent in the upper Tajuña River (Guadalajara, Spain. Four sampling sites were selected over the study area: one site (S-1 placed upstream from the trout farm was used as a reference station; sampling sites S-2, S-3 and S-4 were set, respectively, about 10, 100 and 1000 metres downriver of the trout farm outlet. The river bottom was mainly stony with cobbles and pebbles at S-1, S-3 and S-4, but at S-2 it was covered by a thick layer of organic sediment. Although some macrophyte species (Apium nodiflorum, Groenlandia densa were either absent or fewer downstream of the farm, abundance (% coverage and diversity (number of species for the aquatic macrophyte community as a whole increased. In contrast, epilithic diatoms were completely absent at S-2, and some species (Diploneis parma, Fragilaria ulna, Gomphonema angustatum, Nitzschia dissipata were also absent at S-3 and S-4. Indeed, diatom diversity (number of species was lower at S-3 and S-4 than at S-1. However, diatom abundance (cells/cm2 was higher at S-3 and S-4 than at S-1. Biological indices for diatoms (IBD, TDI indicated a better water quality at S-1 than at S-3 and S-4, with a clear tendency to improve with distance from the fish farm. In contrast, biological indices of macrophytes (IM, IVAMG indicated a similar water quality at S-1, S-3 and S-4, but with bad water quality at S-2. We conclude that epilithic diatoms may be more useful than aquatic macrophytes for biological monitoring of fish farm pollution in fluvial ecosystems. However, as historical and seasonal factors may be relevant to understanding the distribution, abundance and diversity of primary producers in running waters, further studies on long-term seasonal changes are needed to improve the use of macrophyte and diatom indices in assessing fish farm pollution.En este trabajo

  13. Comparative study of the nutritional composition and toxic elements of farmed and wild Chanodichthys mongolicus

    Science.gov (United States)

    Jiang, Haifeng; Cheng, Xiaofei; Geng, Longwu; Tang, Shizhan; Tong, Guangxiang; Xu, Wei

    2017-07-01

    Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements. Proximate composition, amino acid and fatty acid profiles, and toxic elements contents of farmed and wild Chanodichthys mongolicus were established and compared. Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed ( Pacids (TAA), total essential amino acids (TEAA), total non-essential amino acids (TNEAA) and total delicious amino acids (TDAA) in farmed fish were all significantly higher than those in the wild equivalent ( Pacid profiles in both farmed and wild C. mongolicus were dominated by monounsaturated fatty acid (MUFA), with farmed fish contained much more MUFA content compared to wild counterpart ( Pacid (PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than farmed fish ( Pacid (C18:2n6) were the predominant PUFA in wild and farmed C. mongolicus, respectively. Moreover, farmed fish displayed an overall lower toxic element levels (As, Cd, Pb and Hg) in comparison with wild fish, and both were far lower than the established limit standard. In conclusion, our results suggest that the nutritional quality of farmed C. mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition, and therefore further studies should focus on the improving C. mongolicus diet in order to enhance the overall nutritional composition.

  14. Influence of a trout farm on macrozoobenthos communities of the Trešnjica river, Serbia

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    Živić Ivana

    2009-01-01

    Full Text Available Trout farming poses an increasing threat to quality of the water of clean highland streams. Research of this problem has focused primarily on changes in physico-chemical composition of the water and structure of the river bottom, and less on the effects on living organisms. In the present work, we investigated influence of the farm with the highest trout production in Serbia, the 'Riboteks' Trout Farm on the Trešnjica River, on its macrozoobenthos communities. Our investigations showed that the 'Riboteks' Trout Farm wastewaters caused a clear and statistically significant change of moderate intensity in all measured parameters describing the composition and structure of macrozoobenthos communities. These changes were most pronounced in the part of the watercourse closest to the influx of waste water (locality III but remained statistically significant even 500 m downstream (locality IV and were lost only about 3.5 km away from the influx of the farm's wastewater (locality V. The most pronounced were changes in the participation in total abundance of the Baetidae, Chironomidae, and Plecoptera. Additionally, results of the present work confirmed that the mass of fish on the trout farm is a parameter that adequately defines the strength of its action, above all the intensity of its influence on structure of the macrozoobenthos community.

  15. Mesophilic anaerobic treatment of sludge from saline fish farm effluents with biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Gebauer, R. [Finnmark University College, Alta (Norway). Dept. of Aquaculture and Natural Sciences

    2004-06-01

    The mesophilic anaerobic treatment of sludge from saline fish farm effluents (total solids (TS): 8.2-10.2 wt%, chemical oxygen demand (COD): 60-74 g/l, sodium (Na): 10-10.5 g/l) was carried out in continuously stirred tank reactors (CSTRs) at 35 {sup o}C. COD stabilization between 36% and 55% and methane yields between 0.114 and 0.184 l/g COD added were achieved. However, the process was strongly inhibited, presumably by sodium, and unstable, with propionic acid being the main compound of the volatile fatty acids (VFA). When diluting the sludge 1:1 with tap water (Na: 5.3 g/l), the inhibition could be overcome and a stable process with low VFA concentrations was achieved. The results of the study are used to make recommendations for the configuration of full-scale treatment plants for the collected sludge from one salmon farming licence and to estimate the energy production from these plants. (Author)

  16. Flow Structures and Efficiency of Swimming Fish school: Numerical Study

    Science.gov (United States)

    Yatagai, Yuzuru; Hattori, Yuji

    2013-11-01

    The flow structure and energy-saving mechanism in fish school is numerically investigated by using the volume penalization method. We calculate the various patterns of configuration of fishes and investigate the relation between spatial arrangement and the performance of fish. It is found that the down-stream fish gains a hydrodynamic advantage from the upstream wake shed by the upstream fish. The most efficient configuration is that the downstream fish is placed in the wake. It reduces the drag force of the downstream fish in comparison with that in solo swimming.

  17. Infectious bacterial pathogens, parasites and pathological correlations of sewage pollution as an important threat to farmed fishes in Egypt.

    Science.gov (United States)

    Mahmoud, Mahmoud A; Abdelsalam, Mohamed; Mahdy, Olfat A; El Miniawy, Hala M F; Ahmed, Zakia A M; Osman, Ahmed H; Mohamed, Hussein M H; Khattab, A M; Zaki Ewiss, M A

    2016-12-01

    This paper is a part of a multi-disciplinary research "Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins". The project aimed to investigate the environmental impact of implementing sewage water before and after treatment using the effluent of the on-site decentralized Japanese' Johkasou system, in agriculture and producing fish protein. The aim is to establish such system in Egypt to strengthen the sanitary conditions of water resources. In the present study, the impact of the sewage pollution in some fish farms at El-Fayyum, Port Said and El-Dakahlia governorates in Egypt was carried out. Water and fish (Oreochromis niloticus and Mugil cephalus) samples were collected from private fish farms of such localities. Bacteriological and chemical examination of water samples revealed the existence of coliforms and many other bacterial species of significant human health hazards. The chemical parameters of water showed a marked deviation from normal levels while examination of fish flesh specimens indicated contamination with Streptococcus Sp., Staphylococcus Sp., and Salmonella in all examined localities. Other bacterial isolates of human health importance (Morganella morganii, Pseudomonas cepacia and Enterococcos durans) were identified. The parasitological examination revealed the presence of encysted metacercariae (EMC); Diplostomatidae, Prohemistomatidae and Heterphyidae. Moreover, two protozoan parasites (Mxyoboulus tilapiae and Ichthyophthirius multifilis) were also recorded. The histopathological examination revealed mild tissue reaction in case of bacterial infection and severe pathological lesions in different organs in case of EMC infection. Lamellar hyperplasia and mononuclear cell infiltration in branchial tissue was common findings. In skeletal muscles, atrophy of muscle fibres, myolysis and myophagia were detected. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Operational welfare indicators (OWI) in rainbow trout farming

    DEFF Research Database (Denmark)

    Buchmann, Kurt

    2007-01-01

    A number of welfare parameters are defined in order to create tools for the future management of welfare in farmed fish......A number of welfare parameters are defined in order to create tools for the future management of welfare in farmed fish...

  19. The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Petersen, Andreas

    2007-01-01

    Objectives: To determine the genetic basis for tetracycline and sulphonamide resistance and the prevalence of class I and II integrons in oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Methods: A total of 222 isolates were screened for tetracycline resistance...... and Southern blots with sulII and tet(39) probes were performed on selected isolates. Results: The recently identified tetracycline resistance gene tet(39) was demonstrated in 75% (166/222) of oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Isolates that were also...

  20. Fish under exercise

    NARCIS (Netherlands)

    Palstra, A.P.; Planas, J.V.

    2011-01-01

    Improved knowledge on the swimming physiology of fish and its application to fisheries science and aquaculture (i.e., farming a fitter fish) is currently needed in the face of global environmental changes, high fishing pressures, increased aquaculture production as well as increased concern on fish

  1. Environmental DNA for freshwater fish monitoring: insights for conservation within a protected area.

    Science.gov (United States)

    Fernandez, Sara; Sandin, Miguel M; Beaulieu, Paul G; Clusa, Laura; Martinez, Jose L; Ardura, Alba; García-Vázquez, Eva

    2018-01-01

    Many fish species have been introduced in wild ecosystems around the world to provide food or leisure, deliberately or from farm escapes. Some of those introductions have had large ecological effects. The north American native rainbow trout ( Oncorhynchus mykiss Walbaum, 1792) is one of the most widely farmed fish species in the world. It was first introduced in Spain in the late 19th century for sport fishing (Elvira 1995) and nowadays is used there for both fishing and aquaculture. On the other hand, the European native brown trout ( Salmo trutta L.) is catalogued as vulnerable in Spain. Detecting native and invasive fish populations in ecosystem monitoring is crucial, but it may be difficult from conventional sampling methods such as electrofishing. These techniques encompass some mortality, thus are not adequate for some ecosystems as the case of protected areas. Environmental DNA (eDNA) analysis is a sensitive and non-invasive method that can be especially useful for rare and low-density species detection and inventory in water bodies. In this study we employed two eDNA based methods (qPCR and nested PCR-RFLP) to detect salmonid species from mountain streams within a protected area, The Biosphere Reserve and Natural Park of Redes (Upper Nalón Basin, Asturias, Northern Spain), where brown trout is the only native salmonid. We also measured some habitat variables to see how appropriate for salmonids the area is. The sampling area is located upstream impassable dams and contains one rainbow trout fish farm. Employing qPCR methodology, brown trout eDNA was detected in all the nine sampling sites surveyed, while nested PCR-RFLP method failed to detect it in two sampling points. Rainbow trout eDNA was detected with both techniques at all sites in the Nalón River' (n1, n2 and n3). Salmonid habitat units and water quality were high from the area studied. In this study, a high quantity of rainbow trout eDNA was found upstream and downstream of a fish farm located

  2. Environmental DNA for freshwater fish monitoring: insights for conservation within a protected area

    Directory of Open Access Journals (Sweden)

    Sara Fernandez

    2018-03-01

    upstream and downstream of a fish farm located inside a Biosphere Reserve. Unreported escapes from the fish farm are a likely explanation of these results. Since salmonid habitat is abundant and the water quality high, the establishment of rainbow trout populations would be favored should escapes occur. Environmental DNA has here proved to be a valuable tool for species detection in freshwater environments, and the probe-based qPCR highly sensitive technique for detection of scarce species. We would recommend this method for routine monitoring and early detection of introduced species within natural reserves.

  3. Energy productivity and efficiency of the ‘gher’ (prawn-fish-rice) farming system in Bangladesh

    International Nuclear Information System (INIS)

    Rahman, Sanzidur; Barmon, Basanta K.

    2012-01-01

    ‘Gher’ farming is a unique system that incorporates the joint operation of three enterprises: freshwater prawn, fish and HYV rice, and is expanding rapidly in the coastal regions of Bangladesh because of its proven high income earning potential. In this paper, the sustainability of this system is evaluated by analysing its performance in terms of energy use by applying a stochastic distance function approach which revealed interesting and unexpected results. The prawn enterprise which is the key income earning component is found to be technically inefficient while the rice enterprise is found to be efficient. The net energy balance and the energy use efficiency of the ‘gher’ farming system is estimated at 18,510 MJ ha −1 and 1.72 respectively. The ‘gher’ farmers are operating at a very high level of technical (energy) efficiency (92%). Diversification amongst enterprises is associated with technical (energy) inefficiency. However, larger operation size enhances efficiency. The key policy implication is that the ‘gher’ farming system can be sustained in the long run provided that productivity from the rice enterprise remains high. Also, policies to support the expansion of ‘gher’ farm sizes will improve efficiency. -- Highlights: ► Sustainability of gher farming system is evaluated in terms of energy use. ► The prawn enterprise is technically inefficient while rice enterprise is efficient. ► The net energy balance is 18,510 MJ ha -1 and energy use efficiency is 1.72. ► The overall technical (energy) efficiency is very high (92%). ► The gher farming system can be sustained if rice productivity remains high.

  4. Variation of limnological parameters in a tropical lake used for tilapia cage farming

    Directory of Open Access Journals (Sweden)

    Graciele P. Venturoti

    2015-11-01

    Full Text Available The aim of this study was to assess the effects of tilapia cage culture on the water quality and sediment of Palminhas Lake during both the dry and rainy seasons. Eight sites within the lake (four in fish farms and four in areas without fish farms and one site on an affluent stream were sampled monthly from February 2011 to January 2012. Dissolved oxygen and pH were significantly lower at fish farm sites than at locations without farms, while chlorophyll a was higher at fish farm sites. Moreover, large seasonal variations were observed, which were not related to the fish farms. The Secchi disc depth and ammonia nitrogen level were significantly higher during the dry season, but temperature, dissolved oxygen, pH, total phosphorus and chlorophyll a were significantly higher during the rainy season. The affluent stream contributed substantially to lake eutrophication. Palminhas Lake is mesotrophic and has exhibited a progressive worsening in water quality over the past 20 years. These changes were not caused by fish farming alone but probably by other anthropic activities in the areas surrounding the lake.

  5. Economic differential of integrated fish, rice cum piggery and fish ...

    African Journals Online (AJOL)

    Fish, rice cum piggery and fish, rice cum poultry production integration platforms were set up to perfect the ideas of integrated fish farming in Sierra Leone. Water quality parameters measured biweekly included: dissolved oxygen, water temperature, pH, water hardness, water alkalinity, ammonia, nitrate, BOD and nitrite.

  6. Methodology to identify the location of shoals of fish downstream from hydroelectric power plant; Metodologia para identificar a locacao de cardumes de peixes a jusante de UHE

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, C.B.; Viana, E.M.F.; Faria, M.T.C. de [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Centro de Pesquisas Hidraulicas e Recursos Hidricos], Emails: martinez@cce.ufmg.br, ednamariafaria@ufmg.br, mtcdf@uol.com.br

    2009-07-01

    The location identification of fish shoals at the downstream of an hydroelectric power plants is a task of importance especially when one takes into account the need to identify possible locations for the deployment of fish transportation mechanism. This paper presents a methodology based on the use of reduced models, which will be operated during the biological testing, under flow and conditions similar to the field where will be included shoals of fish. These groups will be observed during a period of time under varying conditions of discharge of hydraulic turbines. At the end of this observation it can be identified preferential location areas of fish shoals that will be evaluated later in order to install transposition systems in the place.

  7. Environmental impacts of coastal farming: carbon and nitrogen budgets for trout farming activity in Kaldbaksfjørđur (Faroe Islands)

    DEFF Research Database (Denmark)

    Nordi, Gunnvør a; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated...... derived from fish food settled on the seabed, where it was either mineralized or accumulated in the sediment. Based on transect measurements of diagenetic activity, the farm footprint was found to cover an area ~10 times the farm area. OC mineralization in the sediment increased linearly with increasing...

  8. MOTIVATIONS FOR INVOLVEMENT IN URBAN CATFISH FARMING AND SUSTAINABLE FOOD SECURITY IN NIGERIA

    Directory of Open Access Journals (Sweden)

    Afolabi Monisola TUNDE

    2017-10-01

    Full Text Available Fish farming is known as one of the ways of ensuring food security and alleviating poverty through income generation. It is very common in the urban areas of Nigeria because of great demand for fish. This study determines motivations for involvement in urban catfish farming and sustainable food security in Ilorin, Kwara State, Nigeria. Specifically, the study identifies fish farmers and their socio-demographic characteristics in the study area; it examines motives of fish farming; examines the contributions of fish farming to household food security; and assesses the challenges faced by fish farmers for increased production. Both primary and secondary sources of information were employed and a total of 120 fish farmers were sampled randomly with copies of structured questionnaire. Frequency counts, percentages, tabulations and matrix ranking were employed to analyze the gathered data. The findings revealed that catfish production has actually contributed immensely to sustainable food security by making fish available, accessible and stable within the study area. The main motive for involvement in fish farming by the farmers includes food security (with a mean value of 3.80. This was followed by income supplement (x = 3.50, source of employment (x = 3.42 and increase in price of meat (x = 3.37. It can therefore be concluded that catfish farming in the study area has not only improve practitioners’ food security but has also contributed immensely to their income. The paper recommends the need to include fish farming in urban planning and that it should be encouraged in both rural and urban areas so as to have sustainable food security in the country as a whole.

  9. Agri-aqua farming in Thailand

    OpenAIRE

    Buendia, R.Y.

    1997-01-01

    Integrated agriculture-aquaculture systems have been in existence in Thailand for centuries. This country has the most varied integrated farming operations in southeast Asia; pig, cattle, buffalo, chicken, duck, vegetable, aquatic plant, rice and orchard in combination with fish are practices. The systems most preferred by subsistence farmers are rice-fish, duck-fish and chicken-fish culture. A brief outline is given of these 3 systems.

  10. Cowlitz Falls fish passage

    International Nuclear Information System (INIS)

    1995-09-01

    The upper Cowlitz was once home to native salmon and steelhead. But the combined impacts of overharvest, farming, logging and road building hammered fish runs. And in the 1960s, a pair of hydroelectric dams blocked the migration path of ocean-returning and ocean-going fish. The lower Cowlitz still supports hatchery runs of chinook, coho and steelhead. But some 200 river miles in the upper river basin--much of it prime spawning and rearing habitat--have been virtually cut off from the ocean for over 26 years. Now the idea is to trap-and-haul salmon and steelhead both ways and bypass previously impassable obstacles in the path of anadromous fish. The plan can be summarized, for the sake of explanation, in three steps: (1) trap and haul adult fish--collect ocean-returning adult fish at the lowermost Cowlitz dam, and truck them upstream; (2) reseed--release the ripe adults above the uppermost dam, and let them spawn naturally, at the same time, supplement these runs with hatchery born fry that are reared and imprinted in ponds and net pens in the watershed; (3) trap and haul smolts--collection the new generation of young fish as they arrive at the uppermost Cowlitz dam, truck them past the three dams, and release them to continue their downstream migration to the sea. The critical part of any fish-collection system is the method of fish attraction. Scientists have to find the best combination of attraction system and screens that will guide young fish to the right spot, away from the turbine intakes. In the spring of 1994 a test was made of a prototype system of baffles and slots on the upriver face of the Cowlitz Falls Dam. The prototype worked at 90% efficiency in early tests, and it worked without the kind of expensive screening devices that have been installed on other dams. Now that the success of the attraction system has been verified, Harza engineers and consultants will design and build the appropriate collection part of the system

  11. Homestead fish farmers' production profile in Osun state, Nigeria ...

    African Journals Online (AJOL)

    Homestead fish farming in the Nigeria is carried out by small scale operators in small fresh water ponds. ... fish farmers in Osun state is also characterized by a high level of use of improved fish farming techniques and improved technologies.

  12. Mercury and stable isotope signatures in caged marine fish and fish feeds

    Energy Technology Data Exchange (ETDEWEB)

    Onsanit, Sarayut; Chen, Min; Ke, Caihuan [State Key Laboratory for Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen 361005 (China); Wang, Wen-Xiong [State Key Laboratory for Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen 361005 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Mercury concentrations in caged fish were closely related to Hg concentrations in fish feeds. Black-Right-Pointing-Pointer The trophic transfer factor of methylmercury was dependent on fish feeds, and was the highest for fish fed on pellet feeds. Black-Right-Pointing-Pointer Fish farming may be a good way of reducing the human exposure to Hg because Hg levels can be carefully controlled. - Abstract: Total mercury (THg) and methylmercury (MeHg) concentrations were determined in four species of marine caged carnivorous fish, one species of herbivorous fish and three types of fish feeds (dried pellet feed, forage fish and fish viscera), collected from five cage sites in the rural areas along Fujian coastline, China. For the carnivorous fish, the concentrations of THg and MeHg ranged from 0.03 to 0.31 {mu}g/g and from 0.02 to 0.30 {mu}g/g on wet weight basis, respectively. The concentrations were lower for the herbivorous fish with both within the range of 0.01-0.03 {mu}g/g. Out of the three tested fish feeds, tuna viscera contained the highest level of mercury (0.20 {mu}g/g THg and 0.13 {mu}g/g MeHg), with pellet feed containing the lowest level (0.05 {mu}g/g THg and 0.01 {mu}g/g MeHg). The calculated trophic transfer factor of MeHg was the highest (12-64) for fish fed on pellet feeds, and was the lowest for fish fed on tuna viscera. A significant relationship was found between Hg concentrations in caged fish and in fish feeds, thus Hg was primarily accumulated from the diet. Furthermore, the stable isotope {delta}{sup 15}N was positively correlated with the Hg concentration in two caged sites, indicating that {delta}{sup 15}N may be a suitable tool for tracking mercury in caged fish. We conclude that fish farming may be a good way of reducing the human exposure to Hg because mercury levels can be carefully controlled in such farming systems.

  13. Mercury and stable isotope signatures in caged marine fish and fish feeds

    International Nuclear Information System (INIS)

    Onsanit, Sarayut; Chen, Min; Ke, Caihuan; Wang, Wen-Xiong

    2012-01-01

    Highlights: ► Mercury concentrations in caged fish were closely related to Hg concentrations in fish feeds. ► The trophic transfer factor of methylmercury was dependent on fish feeds, and was the highest for fish fed on pellet feeds. ► Fish farming may be a good way of reducing the human exposure to Hg because Hg levels can be carefully controlled. - Abstract: Total mercury (THg) and methylmercury (MeHg) concentrations were determined in four species of marine caged carnivorous fish, one species of herbivorous fish and three types of fish feeds (dried pellet feed, forage fish and fish viscera), collected from five cage sites in the rural areas along Fujian coastline, China. For the carnivorous fish, the concentrations of THg and MeHg ranged from 0.03 to 0.31 μg/g and from 0.02 to 0.30 μg/g on wet weight basis, respectively. The concentrations were lower for the herbivorous fish with both within the range of 0.01–0.03 μg/g. Out of the three tested fish feeds, tuna viscera contained the highest level of mercury (0.20 μg/g THg and 0.13 μg/g MeHg), with pellet feed containing the lowest level (0.05 μg/g THg and 0.01 μg/g MeHg). The calculated trophic transfer factor of MeHg was the highest (12–64) for fish fed on pellet feeds, and was the lowest for fish fed on tuna viscera. A significant relationship was found between Hg concentrations in caged fish and in fish feeds, thus Hg was primarily accumulated from the diet. Furthermore, the stable isotope δ 15 N was positively correlated with the Hg concentration in two caged sites, indicating that δ 15 N may be a suitable tool for tracking mercury in caged fish. We conclude that fish farming may be a good way of reducing the human exposure to Hg because mercury levels can be carefully controlled in such farming systems.

  14. Market tntegration between farmed and wild fish

    DEFF Research Database (Denmark)

    Bronnmann, Julia; Ankamah-Yeboah, Isaac; Nielsen, Max

    2016-01-01

    Following decade-long growth in worldwide farming of pangasius and tilapia, imports to Germany, a main European market, have been reduced since 2010. One reason for this might be supply growth of wild species at the total German whitefish market, if market integration exists between farmed and wi...

  15. Preliminary aspects concerning phytoplankton structure in the Balta Mare – Carja 1 fish farm

    Directory of Open Access Journals (Sweden)

    Maria FETECAU

    2010-08-01

    Full Text Available The present paper presents information on the structure and the dynamics of the water ecosystem’s phytoplankton of the Carja 1 fish farm - Vaslui County, carps and Asian cyprinids are grown ascommon fish. To establish the structure and the dynamics of the phytoplankton, two samples from 6 stations were taken in the spring and in the autumn, using of a Garmin GPS 7- type navigation system.When analysing the number of individuals and the algae species present in the phytoplankton’s structure, one can notice the low development level of the vegetable plankton. From the quantity point of view, one can notice the numerical abundance of the clorophyceae in all the analysed samples. The dominant species were: Scenedesmus acuminatus, Scenedesmus quadricauda, Tetrastrum staurogenieforme. The small number of species and algae specimens determined in the phytoplankton’s structure emphasizes the reduced level of trophicity and biodiversity of the analysed ecosystem.

  16. Fish farming in «Baetica». The «piscine» of the halieutic site at Trafalgar Cape (Cádiz

    Directory of Open Access Journals (Sweden)

    Darío BERNAL CASASOLA

    2011-10-01

    Full Text Available The present paper presents a structure of Roman date, cut into bedrock, and possibly used for fish farming purposes. So far, this sort of evidence, which is well attested in Italian villae maritimae dating to the Late Republic and the Early Empire, had only been found in the Iberian Peninsula in the southern Tarraconense (coast of Alicante. The above mentioned structure is, therefore, the first of its kind found in the Baetica. Interpretation must combine archaeological evidence for Roman fish farming in Andalusia (ostrearum vivaria at Traducta, current Algeciras and geoarchaeological features; the structure is located in the intertidal zone and enjoys fresh water supply from the nearby halieutic site of Trafalgar Cape (Barbate, Cádiz. This paper aims at the re-interpretation of this coastal site, previously interpreted as a salted products factory, or cetaria, but the topographical and architectural features of which (vats with inner steps, cisterns, terraced structures, etc. are rather suggestive of a villa maritima or a complex centre for the exploitation of marine resources.

  17. Environmental radiological studies downstream from the Rancho Seco Nuclear Power Generating Station, 1985

    International Nuclear Information System (INIS)

    Noshkin, V.E.; Wong, K.M.; Eagle, R.J.; Brunk, J.L.; Jokela, T.A.

    1986-01-01

    Information compiled in 1985 while assessing the environmental impact of radionuclides previously discharged with aqueous releases from the Rancho Seco Nuclear Power Generating Plant is presented. In October 1984, the quantities of gamma-emitting radionuclides in water discharged to Clay Creek from the plant were reduced below operationally defined detection limits for liquid effluents. However, radionuclides previously discharged persist in the downstream environment and are found in many aquatic dietary components. 134 Cs and 137 Cs are the primary gamma-emitting radionuclides detected in the edible flesh of different fish, crayfish, and frogs. Coefficients for exponential equations are generated, from a least square analysis, that relate the change in concentration of 137 Cs in fish to distance downstream and time between March and October 1985. Concentrations of 137 Cs in surface creek sediments also decreased in the downstream direction much in the same manner as concentrations decreased in fish. However, there was no significant difference in the radiocesium concentrations in surface sediements collected from comparable locations during both 1984 and 1985

  18. Consumers’ attitude towards fish meat

    Directory of Open Access Journals (Sweden)

    Francesca Conte

    2014-09-01

    Full Text Available The overall aim of this paper is to show the factors that may affect consumers’ attitude towards farmed fish products. Consumers ask new products on the basis of different quality attributes: stability, safety, composition, better health effects, environment protection, etc. Different and controversial opinions on farmed and wild fish are also explored by literature review. The authors pay attention also to fish welfare as an emerging issue and effective information about fish products as a factor exerting a positive influence on consumers’ decision of purchase. Some relevant legislative notes on the paper’s topics are also cited. The qualitative aspects of aquaculture fish and the consumers’ demand and choice need further studies, according to some factors, such as the changing consumers’ attitudes towards fish products, the different fish quality perception and the development in the aquaculture systems.

  19. Dam crossing by migrating fish. State of the technique

    International Nuclear Information System (INIS)

    Travade, F.; Larinier, M.

    1992-01-01

    In the first part of this paper, the present state of design of fish ways is reviewed, focusing on the interest and the limits of each type of fish facility. The second part deals with downstream migration problems at hydroelectric power plants: fish damage in spillways and hydraulic turbines and design of fish screening and other diversionary techniques used to prevent entry of downstream migrant into intakes. 14 refs., 13 figs

  20. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru

    Directory of Open Access Journals (Sweden)

    Aubrey L. Langeland

    2017-03-01

    Full Text Available Artisanal and small-scale gold mining (ASGM has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1 examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO Expert Committee of Food Additives (JECFA’s Provisional Tolerable Weekly Intake (PTWI; and (2, to measure the mercury levels of paco (Piaractus brachypomus fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight. We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute

  1. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

    Science.gov (United States)

    Langeland, Aubrey L; Hardin, Rebecca D; Neitzel, Richard L

    2017-03-14

    Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO) Expert Committee of Food Additives (JECFA)'s Provisional Tolerable Weekly Intake (PTWI); and (2), to measure the mercury levels of paco ( Piaractus brachypomus ) fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight). We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred) in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute to human

  2. A historical review of the key bacterial and viral pathogens of Scottish wild fish.

    Science.gov (United States)

    Wallace, I S; McKay, P; Murray, A G

    2017-12-01

    Thousands of Scottish wild fish were screened for pathogens by Marine Scotland Science. A systematic review of published and unpublished data on six key pathogens (Renibacterium salmoninarum, Aeromonas salmonicida, IPNV, ISAV, SAV and VHSV) found in Scottish wild and farmed fish was undertaken. Despite many reported cases in farmed fish, there was a limited number of positive samples from Scottish wild fish, however, there was evidence for interactions between wild and farmed fish. A slightly elevated IPNV prevalence was reported in wild marine fish caught close to Atlantic salmon, Salmo salar L., farms that had undergone clinical IPN. Salmonid alphavirus was isolated from wild marine fish caught near Atlantic salmon farms with a SAV infection history. Isolations of VHSV were made from cleaner wrasse (Labridae) used on Scottish Atlantic salmon farms and VHSV was detected in local wild marine fish. However, these pathogens have been detected in wild marine fish caught remotely from aquaculture sites. These data suggest that despite the large number of samples taken, there is limited evidence for clinical disease in wild fish due to these pathogens (although BKD and furunculosis historically occurred) and they are likely to have had a minimal impact on Scottish wild fish. © 2017 Crown Copyright. Journal of Fish Diseases © 2017 John Wiley & Sons Ltd.

  3. Evaluation of Application Space Expansion for the Sensor Fish

    Energy Technology Data Exchange (ETDEWEB)

    DeRolph, Christopher R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bevelhimer, Mark S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-02-01

    The Pacific Northwest National Laboratory has developed an instrument known as the sensor fish that can be released into downstream passage routes at hydropower facilities to collect data on the physical conditions that a fish might be exposed to during passage through a turbine. The US Department of Energy Wind and Water Power Program sees value in expanding the sensor fish application space beyond large Kaplan turbines in the northwest United States to evaluate conditions to which a greater variety of fish species are exposed. Development of fish-friendly turbines requires an understanding of both physical passage conditions and biological responses to those conditions. Expanding the use of sensor fish into other application spaces will add to the knowledge base of physical passage conditions and could also enhance the use of sensor fish as a site-specific tool in mitigating potential impacts to fish populations from hydropower. The Oak Ridge National Laboratory (ORNL) National Hydropower Assessment Program (NHAAP) database contains hydropower facility characteristics that, along with national fish distribution data, were used to evaluate potential interactions between fish species and project characteristics related to downstream passage issues. ORNL developed rankings for the turbine types in the NHAAP database in terms of their potential to impact fish through injury or mortality during downstream turbine passage. National-scale fish distributions for 31 key migratory species were spatially intersected with hydropower plant locations to identify facilities where turbines with a high threat to fish injury or mortality overlap with the potential range of a sensitive fish species. A dataset was produced that identifies hydropower facilities where deployment of the sensor fish technology might be beneficial in addressing issues related to downstream fish passage. The dataset can be queried to target specific geographic regions, fish species, license expiration

  4. Evaluation of the use of fresh water by four Egyptian farms applying integrated aquaculture – agriculture

    NARCIS (Netherlands)

    Heijden, van der P.G.M.; Nasr-Alla, A.; Kenawy, D.; El-Naggar, G.; Beveridge, M.

    2012-01-01

    This report describes a study done in 2010 by researchers of the WorldFish Center on water use in Egyptian farms that apply aquaculture – agriculture integration. Two of the four farms that were monitored derived the main income from farming and selling fish, the two other farms were mainly

  5. Downstream fish passage guide walls: A hydraulic scale model analysis

    Science.gov (United States)

    Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

    2018-01-01

    Partial-depth guide walls are used to improve passage efficiency and reduce the delay of out-migrating anadromous fish species by guiding fish to a bypass route (i.e. weir, pipe, sluice gate) that circumvents the turbine intakes, where survival is usually lower. Evaluation and monitoring studies, however, indicate a high propensity for some fish to pass underneath, rather than along, the guide walls, compromising their effectiveness. In the present study we evaluated a range of guide wall structures to identify where/if the flow field shifts from sweeping (i.e. flow direction primarily along the wall and towards the bypass) to downward-dominant. Many migratory fish species, particularly juveniles, are known to drift with the flow and/or exhibit rheotactic behaviour during their migration. When these behaviours are present, fish follow the path of the flow field. Hence, maintaining a strong sweeping velocity in relation to the downward velocity along a guide wall is essential to successful fish guidance. Nine experiments were conducted to measure the three-dimensional velocity components upstream of a scale model guide wall set at a wide range of depths and angles to flow. Results demonstrated how each guide wall configuration affected the three-dimensional velocity components, and hence the downward and sweeping velocity, along the full length of the guide wall. In general, the velocities produced in the scale model were sweeping dominant near the water surface and either downward dominant or close to the transitional depth near the bottom of the guide wall. The primary exception to this shift from sweeping do downward flow was for the minimum guide wall angle tested in this study (15°). At 15° the flow pattern was fully sweeping dominant for every cross-section, indicating that a guide wall with a relatively small angle may be more likely to produce conditions favorable to efficient guidance. A critical next step is to evaluate the behaviour of migratory fish as

  6. An overview of the sustainability of rice agroecosystem through rice-fish integration

    International Nuclear Information System (INIS)

    Ahyaudin Ali

    2002-01-01

    Rice-fish integration in the rice agroecosystem has been introduced and is expanding in Malaysia. This type of farm integration has resulted in land optimization, thus enabling farmers to grow both fish and rice in one farming system. Introducing fish into the ricefield has also increased seasonal income as well as reduced pesticide use. Although basic ecological knowledge on rice-fish integration has allowed rice-fish integration to be introduced, further research is required to allow for fine tuning of the methodologies used. Thus research on the ecology, management, production methods and the characterization of rice-fish farming system of Malaysia is needed. Further characterization and description is needed on the ecology of the rice-fish farming system of Malaysia in terms of production, food webs, nutrient flow and system diversity. To increase the sustainability efficiency and productivity of the system, implementation of management techniques formulated through research is required. (Author)

  7. Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus).

    Science.gov (United States)

    Besson, M; Komen, H; Aubin, J; de Boer, I J M; Poelman, M; Quillet, E; Vancoillie, C; Vandeputte, M; van Arendonk, J A M

    2014-12-01

    In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal growth coefficient (TGC) and the feed conversion ratio (FCR). This approach was applied to a farm producing African catfish (Clarias gariepinus) in a recirculating aquaculture system (RAS). In the RAS, 2 factors could limit production level: the nitrogen treatment capacity of the biofilter or the fish density in rearing tanks at harvest. Profit calculation includes revenue from fish sales, cost of juveniles, cost of feed, cost of waste water treatment, and fixed costs. In the reference scenario, profit was modeled to zero. EV were calculated as the difference in profit per kilogram of fish between the current population mean for both traits (µt) and the next generation of selective breeding (µt+Δt) for either TGC or FCR. EV of TGC and FCR were calculated for three generations of hypothetical selection on either TGC or FCR (respectively 6.8% and 7.6% improvement per generation). The results show that changes in TGC and FCR can affect both the number of fish that can be stocked (number of batches per year and number of fish per batch) and the factor limiting production. The EV of TGC and FCR vary and depend on the limiting factors. When dissolved NH3-N is the limiting factor for both µt and µt+Δt, increasing TGC decreases the number of fish that can be stocked but increases the number of batches that can be grown. As a result, profit remains constant and EVTGC is zero. Increasing FCR, however, increases the number of fish stocked and the ratio of fish produced per kilogram of feed consumed ("economic efficiency"). The EVFCR is 0.14 €/kg of fish, and profit per kilogram of fish increases by about 10%. When density is the limiting factor for both µt and µt+Δt, the

  8. Longitudinal habitat disruption in Neotropical streams: fish assemblages under the influence of culverts

    Directory of Open Access Journals (Sweden)

    José Roberto Mariano

    Full Text Available This study assessed differences in fish assemblages existing upstream and downstream two types of culverts, one on each of two different Neotropical streams. We analyzed the composition and structure of the ichthyofauna and tested for spatial patterns. Fish sampling was carried out monthly between November 2009 and October 2010 using different fishing gears. We collected 2,220 fish of 33 species; 901 in stretches of the Lopeí stream - circular culvert and 1,310 in stretches of the Pindorama stream - box culvert. Fish abundance was similar in upstream and downstream stretches of the circular culvert, whereas it was slightly higher in the upstream than downstream stretch for the box culvert. Characiformes predominated in the upstream stretch of both culverts. On the other hand, Siluriformes was abundant in the downstream stretch of the circular culvert, with similar abundance in the stretches of the box culvert. Species richness and diversity (Shannon-Weiner Index were higher in the downstream stretch of the circular culvert, but they were similar in both stretches of the box culvert. The most abundant species were Astyanax altiparanae, A. paranae, A. fasciatus, Ancistrus sp., and Hypostomus sp. The last two species were more abundant in the downstream stretch of the circular culvert, and similar in stretches of the box culvert. Our study indicated variations in the species abundance, richness, and diversity between upstream and downstream stretches in particular of the circular culvert in the Lopeí stream, suggesting that fish movements are restrained more intensively in this culvert, especially for Siluriformes. The drop in the circular culvert outlet probably created passage barriers especially for those fish that has no ability to jump, where downstream erosion could lead to culvert perching. Studies on appropriate road crossing design or installation are fundamental whereas improvements in these structures can restore the connectivity of

  9. Fish welfare in capture fisheries

    NARCIS (Netherlands)

    Veldhuizen, L.J.L.; Berentsen, P.B.M.; Boer, de I.J.M.; Vis, van de J.W.; Bokkers, E.A.M.

    2018-01-01

    Concerns about the welfare of production animals have extended from farm animals to fish, but an overview of the impact of especially capture fisheries on fish welfare is lacking. This review provides a synthesis of 85 articles, which demonstrates that research interest in fish welfare in capture

  10. Wind farm production estimates

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Larsen, Gunner Chr.; Aagaard Madsen, Helge

    2012-01-01

    In this paper, the Dynamic Wake Meandering (DWM) model is applied for simulation of wind farm production. In addition to the numerical simulations, measured data have been analyzed in order to provide the basis for a full-scale verification of the model performance. The basic idea behind the DWMm......In this paper, the Dynamic Wake Meandering (DWM) model is applied for simulation of wind farm production. In addition to the numerical simulations, measured data have been analyzed in order to provide the basis for a full-scale verification of the model performance. The basic idea behind...... the DWMmodel is to model the in- stationary wind farm flow characteristics by considering wind turbine wakes as passive tracers continuously emitted from the wind farm turbines each with a downstream transport pro- cess dictated by large scale turbulent eddies (lateral and ver- tical transportation; i.......e. meandering) and Taylor advection. For the present purpose, the DWM model has been im- plemented in the aeroelastic code HAWC2 [1], and the per- formance of the resulting model complex is mainly verified by comparing simulated and measured loads for the Dutch off-shore Egmond aan Zee wind farm [2]. This farm...

  11. Environmental hedging: A theory and method for reconciling reservoir operations for downstream ecology and water supply

    Science.gov (United States)

    Adams, L. E.; Lund, J. R.; Moyle, P. B.; Quiñones, R. M.; Herman, J. D.; O'Rear, T. A.

    2017-09-01

    Building reservoir release schedules to manage engineered river systems can involve costly trade-offs between storing and releasing water. As a result, the design of release schedules requires metrics that quantify the benefit and damages created by releases to the downstream ecosystem. Such metrics should support making operational decisions under uncertain hydrologic conditions, including drought and flood seasons. This study addresses this need and develops a reservoir operation rule structure and method to maximize downstream environmental benefit while meeting human water demands. The result is a general approach for hedging downstream environmental objectives. A multistage stochastic mixed-integer nonlinear program with Markov Chains, identifies optimal "environmental hedging," releases to maximize environmental benefits subject to probabilistic seasonal hydrologic conditions, current, past, and future environmental demand, human water supply needs, infrastructure limitations, population dynamics, drought storage protection, and the river's carrying capacity. Environmental hedging "hedges bets" for drought by reducing releases for fish, sometimes intentionally killing some fish early to reduce the likelihood of large fish kills and storage crises later. This approach is applied to Folsom reservoir in California to support survival of fall-run Chinook salmon in the lower American River for a range of carryover and initial storage cases. Benefit is measured in terms of fish survival; maintaining self-sustaining native fish populations is a significant indicator of ecosystem function. Environmental hedging meets human demand and outperforms other operating rules, including the current Folsom operating strategy, based on metrics of fish extirpation and water supply reliability.

  12. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    Full Text Available Although dozens of fish ladders have been constructed at dams of Brazilian reservoirs, there are few studies evaluating their efficiency as a tool for the conservation of Neotropical ichthyofauna, especially for migratory species. Therefore, the present study evaluated the selectivity of the species that entered and ascended the fish ladder located next to Lajeado Dam (Luis Eduardo Magalhães Hydroelectric Power Plant on the Tocantins River. Samples were taken monthly from November, 2002 through October, 2003, in the resting pools of the ladder, using cast nets, and in the downstream stretch, using gillnets. The selectivity of the ladder in attracting fish was evaluated by comparing the occurrence, relative abundance, dominance and the congruence of abundance ranks of migratory and non-migratory species in the ladder and in the stretch of river immediately downstream. Species richness and fish abundance in the resting pools were used to evaluate selectivity along the ladder. The effects on selectivity by temporal variations in water level downriver and maximum flow velocity in the fish ladder were also analyzed. Out of the 130 species recorded downriver, 62.3% were caught in the ladder, and migratory species were clearly favored. However, more than 2/3 of the catch belonged to only three species (Rhaphiodon vulpinus, Psectrogaster amazonica and Oxydoras niger. Although the majority of the species that entered the ladder were able to reach its top, there was a sharp reduction in abundance of individuals towards the top. Temporal variations in the water level below the dam influenced richness and abundance of fish concentrated downstream and in the ladder, with lower values during periods of low water. In the ladder, a maximum flow velocity of 2.3 m/s, although also selective, proved to be more appropriate for fish ascension than a velocity of 2.8 m/s. It was concluded that the entry and ascension of the fish in the ladder were not congruent with

  13. Effects of Changes in Food Supply at the Time of Sex Differentiation on the Gonadal Transcriptome of Juvenile Fish. Implications for Natural and Farmed Populations

    OpenAIRE

    Díaz, Noelia; Ribas, Laia; Piferrer, Francesc

    2014-01-01

    Background: Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish. Methods and Findings: This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1) 4-month-old sexually undif...

  14. A Study of Fish Lice (Argulus Sp.) Infection in Freshwater Food Fish

    OpenAIRE

    Aalberg K.; Koščová L.; Šmiga Ľ.; Košuth P.; Koščo J.; Oros M.; Barčák D.; Lazar P.

    2016-01-01

    Argulus sp., commonly referred to as fish lice, are crustacean ectoparasites of fishes. The hematophagous parasites attach to and feed off the integument of their hosts. Outbreaks of epizootics have been reported worldwide, causing mass mortalities and having serious economic implications for fish farms and culture efforts. Argulus fish lice may also serve as vectors of infectious diseases and as intermediate hosts of other parasites. Two native European species, A. foliaceus and A. coregoni,...

  15. Intracellular Bacterial Infections: A Challenge for Developing Cellular Mediated Immunity Vaccines for Farmed Fish

    Directory of Open Access Journals (Sweden)

    Hetron Mweemba Munang’andu

    2018-04-01

    Full Text Available Aquaculture is one of the most rapidly expanding farming systems in the world. Its rapid expansion has brought with it several pathogens infecting different fish species. As a result, there has been a corresponding expansion in vaccine development to cope with the increasing number of infectious diseases in aquaculture. The success of vaccine development for bacterial diseases in aquaculture is largely attributed to empirical vaccine designs based on inactivation of whole cell (WCI bacteria vaccines. However, an upcoming challenge in vaccine design is the increase of intracellular bacterial pathogens that are not responsive to WCI vaccines. Intracellular bacterial vaccines evoke cellular mediated immune (CMI responses that “kill” and eliminate infected cells, unlike WCI vaccines that induce humoral immune responses whose protective mechanism is neutralization of extracellular replicating pathogens by antibodies. In this synopsis, I provide an overview of the intracellular bacterial pathogens infecting different fish species in aquaculture, outlining their mechanisms of invasion, replication, and survival intracellularly based on existing data. I also bring into perspective the current state of CMI understanding in fish together with its potential application in vaccine development. Further, I highlight the immunological pitfalls that have derailed our ability to produce protective vaccines against intracellular pathogens for finfish. Overall, the synopsis put forth herein advocates for a shift in vaccine design to include CMI-based vaccines against intracellular pathogens currently adversely affecting the aquaculture industry.

  16. SUGGESTIONS OF SCENARIOS FOR RESTORING LONGITUDINAL CONNECTIVITY TO SUSTAIN FISH FAUNA MIGRATION UPSTREAM AND DOWNSTREAM OF APAHIDA BOTTOM SILL

    Directory of Open Access Journals (Sweden)

    Razvan VOICU

    2016-12-01

    Full Text Available Rivers and their corridors form complex ecosystems that include adjacent land, flora and fauna and the actual courses of water. Given the ecological criteria for prioritizing the rehabilitation of longitudinal continuity of watercourses recommended by the International Commission for Protection of the Danube River (ICPDR (Appendix 1 and starting from the analysis of the Management Plan to ensure longitudinal continuity of watercourses in Some?-Tisa River Area (Annex 9.17.a in BMP – Basin Management Plan there have been proposed several scenarios in order to facilitate fish species migration above the bottom sill from Apahida. The selected case study is focused on the mentioned discharge or bottom sill in Apahida town (hm 985 located 45 m downstream of the bridge located at the intersection of two streets; this bottom sill is 0.8 m high and was built in order to correct the slope, to reduce erosion and to enhance water oxygenation. Currently the bottom sill is supervised by Some?-Tisa River Basin Water Administration, Cluj SGA. One of the important migratory fish species in the study area is the Common Nase (Chondrostoma nasus protected by Bern Convention (Appendix III; barbel (Barbus barbus- rare species, protected Habitats Directive (Annex V,annex 4A of Low nr.462 and Red List of RBDD; bream (Abramis brama bream (Abramis brama - IUCN Red List of Threatened Species. The water catchment area of the Apahida commune in Cluj County blocks migration of various species of migratory fish such as: Common Nase (Chondrostoma nasus protected by the Bern Convention (Appendix III; Barbel (Barbus barbus - rare species, protected Habitats Directive (Annex V, Annex 4A of Low No 462 and Red List of RBDD; Bream (Abramis brama Bream (Abramis brama - IUCN Red List of Threatened Species. To help the three species of fish come the solutions proposed in this article.

  17. Farming the Sea

    Science.gov (United States)

    Morgan, William

    1971-01-01

    Florida has initiated a training program in an entirely new dimension--Sea Farming. Presented is a description of the vocational agriculture program designed to teach propagation, cultivation, harvesting, marketing, and conservation practices related to production of oysters, shrimp, scallops, crabs, and fin fishes. (Editor/GB)

  18. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Science.gov (United States)

    Manthey-Karl, Monika; Lehmann, Ines; Ostermeyer, Ute; Schröder, Ute

    2016-01-01

    To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus) and barramundi (Lates calcarifer) and of farmed pangasius (Pangasianodon hypophthalmus). The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1) were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable. PMID:28231154

  19. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Directory of Open Access Journals (Sweden)

    Monika Manthey-Karl

    2016-08-01

    Full Text Available To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus and barramundi (Lates calcarifer and of farmed pangasius (Pangasianodon hypophthalmus. The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1 were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable.

  20. Biomagnification of organochlorine pollutants in farmed and wild gilthead sea bream (Sparus aurata) and stable isotope characterization of the trophic chains

    International Nuclear Information System (INIS)

    Serrano, Roque; Blanes, Miguel A.; Lopez, Francisco J.

    2008-01-01

    Organochlorine pollutants (pesticides and polychlorinated biphenyls) were analysed in farmed and wild gilthead sea bream (Sparus aurata) tissues (white muscle and liver) from the Western Mediterranean (Spain) and in their diets. Determination was carried out by gas chromatography coupled to tandem mass spectrometry after clean up of the fatty extracts by normal phase HPLC, with detection limits around 0.1 ng/g. Carbon and nitrogen stable isotope ratios were also determined in the samples. Organochlorine compounds concentration was found to be uniform throughout the year in farmed fish, in both white muscle and liver. In contrast, wild fish showed contamination profiles that reflect environmental factors and the biological cycle. Although biomagnification factors for white muscle and liver were found to be 2.4 and 3.0, respectively for farmed fish, and 0.15 and 0.54 for wild specimens, wild fish presented higher levels of organochlorine contaminants than farmed fish. Nitrogen stable isotopes determination in muscle from wild and farmed sea bream during the year gave us a profile related to the biological cycle. δ 15 N mean values from farmed fish were 2.0 per mille higher than from wild fish throughout the year that corresponding to close to one trophic step. δ 13 C values were stable during the year, and also more enriched in the case of farmed fish. The low levels of contaminants found in the feed supplied to farmed fish explain the organochlorine concentrations in their tissues which remain below wild fish, in spite of the intensive culture conditions and higher trophic level of cultured specimens

  1. Biomagnification of organochlorine pollutants in farmed and wild gilthead sea bream (Sparus aurata) and stable isotope characterization of the trophic chains

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Roque [Research Institute for Pesticides and Water (IUPA). Avda Sos Baynat, s/n. University Jaume I, 12071 Castellon (Spain)], E-mail: serrano@qfa.uji.es; Blanes, Miguel A.; Lopez, Francisco J. [Research Institute for Pesticides and Water (IUPA). Avda Sos Baynat, s/n. University Jaume I, 12071 Castellon (Spain)

    2008-01-25

    Organochlorine pollutants (pesticides and polychlorinated biphenyls) were analysed in farmed and wild gilthead sea bream (Sparus aurata) tissues (white muscle and liver) from the Western Mediterranean (Spain) and in their diets. Determination was carried out by gas chromatography coupled to tandem mass spectrometry after clean up of the fatty extracts by normal phase HPLC, with detection limits around 0.1 ng/g. Carbon and nitrogen stable isotope ratios were also determined in the samples. Organochlorine compounds concentration was found to be uniform throughout the year in farmed fish, in both white muscle and liver. In contrast, wild fish showed contamination profiles that reflect environmental factors and the biological cycle. Although biomagnification factors for white muscle and liver were found to be 2.4 and 3.0, respectively for farmed fish, and 0.15 and 0.54 for wild specimens, wild fish presented higher levels of organochlorine contaminants than farmed fish. Nitrogen stable isotopes determination in muscle from wild and farmed sea bream during the year gave us a profile related to the biological cycle. {delta}{sup 15}N mean values from farmed fish were 2.0 per mille higher than from wild fish throughout the year that corresponding to close to one trophic step. {delta}{sup 13}C values were stable during the year, and also more enriched in the case of farmed fish. The low levels of contaminants found in the feed supplied to farmed fish explain the organochlorine concentrations in their tissues which remain below wild fish, in spite of the intensive culture conditions and higher trophic level of cultured specimens.

  2. Biometric and metabolic profiles associated to different rearing conditions in offshore farmed gilthead sea bream (Sparus aurata L.).

    Science.gov (United States)

    Melis, Riccardo; Anedda, Roberto

    2014-06-01

    Modern multivariate methods are applied to both biometric measurements and NMR metabolic profiling of fillet to discriminate farmed gilthead sea bream reared in different farming conditions. Two fish groups having the same average size, from the same farm, were caught in May and October. Biometric data demonstrate that condition factor is higher for the leaner fish, sampled in May, while liver somatic index is lower in fish sampled in October. Biometric features are related to metabolic changes that involve lipid storage from May to September, and their mobilization from muscle and liver during prespawning season (September, October). Structural phospholipids (phosphatidylcholine, phosphatidylethanolamine) and essential fatty acids (eicosapentaenoic and docosahexaenoic acids) characterize the lipid profile of the May catch, while triglycerides, monounsaturated and diunsaturated fatty acids, likely from absorption of vegetable oil components of feeds, suggest fish fattening in the warm season and discriminate fish caught in October. Among polar metabolites, taurine, glutamine, glycine, alanine, and creatine/phosphocreatine confirm their role as good biomarkers for the discrimination among fish produced in different farming conditions, especially involving feed digestion and metabolism, chronic stress, and alteration of energetic balance in cage-reared fish. Qualitative traits of farmed fish are therefore the result of a complex combination of environmental factors and farming practices, which should be analyzed to increase consumers' and farmers' awareness. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Measurement of velocity deficit at the downstream of a 1:10 axial hydrokinetic turbine model

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Budi [ORNL; Neary, Vincent S [ORNL; Hill, Craig [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414; Chamorro, Leonardo [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414

    2012-01-01

    Wake recovery constrains the downstream spacing and density of turbines that can be deployed in turbine farms and limits the amount of energy that can be produced at a hydrokinetic energy site. This study investigates the wake recovery at the downstream of a 1:10 axial flow turbine model using a pulse-to-pulse coherent Acoustic Doppler Profiler (ADP). In addition, turbine inflow and outflow velocities were measured for calculating the thrust on the turbine. The result shows that the depth-averaged longitudinal velocity recovers to 97% of the inflow velocity at 35 turbine diameter (D) downstream of the turbine.

  4. Seasonal comparison of wild and farmed brown trout (Salmo trutta forma fario L., 1758): crude lipid, gonadosomatic index and fatty acids.

    Science.gov (United States)

    Kaya, Yalçin; Erdem, Mehmet Emіn

    2009-08-01

    Brown trout is one of the most preferred wild freshwater fish species in the east Black Sea region (Turkey) due to its nutritional value and palatable aroma as well as being popular for sport fishing. In this research, seasonal variations in the crude lipid, gonadosomatic index and fatty acid composition of wild and farmed brown trout were investigated. The spawning period of wild and farmed brown trout appears to be from August to October and from October to January, respectively. The mean crude lipid content in farmed brown trout (3.62%) was significantly higher (P≤0.05) than that of wild brown trout (2.80%). Significant seasonal differences (P≤0.05) in crude lipid content were observed in both fish. The percentage of total saturated fatty acids was similar (P≥0.05) in both fish. Total polyunsaturated fatty acids were higher (P≤0.05) in the wild brown trout compared with the farmed brown trout, while its total monounsaturated fatty acids content was lower (P≤0.05). The muscle lipids of wild fish contained significantly (P≤0.05) higher percentages of C16:1n-7, C17:1n-7, C18:3n-3, C20:2n-6, C20:4n-6, C20:5n-3 and C22:2n-6 fatty acids and contained lower percentages of C14:0, C18:1n-9, C18:2n-6, C20:1n-9, C24:1n-9 and C22:6n-3 fatty acids than farmed fish. The total amounts of n-3 fatty acids in wild fish were higher than in farmed fish, but total amounts of n-6 fatty acids in farmed fish were higher than in wild fish. The n3/n6 proportion in wild fish was higher than that of farmed fish.

  5. Spatial complementarity of forests and farms: accounting for ecosystem services

    Science.gov (United States)

    Subhrendu K. Pattanayak; David T. Butry

    2006-01-01

    Our article considers the economic contributions of forest ecosystem services, using a case study from Flores, Indonesia, in which forest protection in upstream watersheds stabilize soil and hydrological flows in downstream farms. We focus on the demand for a weak complement to the ecosystem services--farm labor-- and account for spatial dependence due to economic...

  6. Levels of polychlorinated dibenzo(p)dioxins, dibenzofurans and dioxin-like PCBs in Irish farmed salmon

    Energy Technology Data Exchange (ETDEWEB)

    Gruemping, R.; Hamm, S.; Stegemann, D.; Maulshagen, A. [eurofins/GfA, Muenster (Germany)

    2004-09-15

    A recent survey published by Hites in the journal Science compared the level of organochlorine contaminants including PCBs and dioxins in farmed versus wild salmon collected from around the world. Most organochlorine substances analysed in the study show a significantly higher concentration level in farmed than in wild salmon. While dioxin and PCB levels of wild fish mainly reflect the contamination level of the environment in which the fish is grown, the dioxin and PCB concentration in farmed fish may mainly be attributed to the fish feed used. In January 2004, the Irish Sea Fisheries Board (BIM) conducted the present study on the concentration of Polychlorinated Dibenzo(p)dioxins (PCDDs), Dibenzofurans (PCDFs) and dioxinlike PCBs (WHO-PCBs) in farmed salmon from two locations in Ireland. The present study should examine whether the PCDD/F and WHO-PCB levels of Irish farmed salmon correlate to the dioxin data for farmed Atlantic salmon from other countries in Northern Europe (e.g. Scotland, Faroe Islands and Norway) presented in the study by Hites. In the Hites survey, raw salmon filets with skin on were tested. Since PCBs, dioxins and other organic pollutants are mainly bound to the fish fat, a reduction of fat content by removal of the skin was supposed to lower the amount of organic contaminants. Thus, the effect of skin removal on the dioxin and PCB levels was also examined in the present study. In addition, the influence of cooking the fish meat was investigated.

  7. Caracterização da piscicultura na região do Vale do Ribeira - SP Characterization of fish farming in the Ribeira Valley region - SP

    Directory of Open Access Journals (Sweden)

    Daniela Castellani

    2005-02-01

    Full Text Available Este trabalho buscou caracterizar a piscicultura na Região do Vale do Ribeira quanto aos sistemas de manejo. Estudaram-se quarenta e duas pisciculturas sendo que, destas, 36 praticam o sistema semi-intensivo e seis o sistema intensivo, com os seguintes objetivos: engorda de peixes, produção de alevinos e pesque-pagues. Foram listadas 41 espécies de peixes cultivadas. Apenas 6 espécies são nativas da Bacia do Rio Ribeira de Iguape: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier e Valenciennes, 1928, jundiá (Rhamdia quelen Quoy e Gaimard, 1824, cascudo (Hypostomus sp Marschall, 1873 e cará (Geophagus brasiliensis Quoy e Gaimard, 1824. Em 95% das pisciculturas foram verificadas fugas de peixes exóticos e alóctones dos cultivos. A tilápia nilótica (Oreochromis niloticus Linneaus, 1758 foi a espécie mais freqüente em escapes, e também é a segunda mais cultivada pelos piscicultores, perdendo somente para o pacu (Piaractus mesopotamicus Halmberg, 1887. Foi possível verificar mediante o cálculo da conversão alimentar, que há um desperdício anual de cerca de 32% da ração utilizada nos cultivos pesquisados. A piscicultura encontra-se em plena expansão nesta região, e já representa a atividade agropecuária mais importante após a bananicultura.The aim of this work was to characterize the fish farming in the Ribeira de Iguape Basin, southern São Paulo State (Brazil, in relation to the management systems. Forty two farms were studied. A semi-intensive system is used by 36 farmers, while an intensive system is used only by 6 studied farmers. Their objectives were raising fish, juvenile fish production and sportive fishery. Forty one fish species were found to be cultivated, but only six were native species from Ribeira Valley: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier and Valenciennes, 1928, jundi

  8. Fish screens at hydroelectric diversions

    International Nuclear Information System (INIS)

    Ott, R.F.

    1994-01-01

    Preventing downstream migrating fish from entering the turbines at hydroelectric projects is a standard mitigation goal of state and federal fishery management agencies. The object is to minimize the adverse impacts to the fish associated with the exclusion and passage through the bypass water conveyance facilities. In the western United States, most of the fishery management agencies have fish screen design criteria that focus on the approach and transportational velocities, maximum opening dimensions of the screen material, and the cleaning standards. Recently, more attention has been given to fish behavioral traits such as attraction and sustained and darting swimming speed, which has resulted in more attention to the position of the screens to the flow and the length of time the downstream migrants are exposed to the screens. Criteria for length of time of exposure, size and position of bypass, flow and velocities in the bypass entrances, discharge requirements back into the receiving water, and exposure to predation have created unique challenges to the fish screen designer. This paper discusses some of the more recent types of fixed fish screens that are being installed at hydroelectric plants that meet these challenges

  9. THE GENETIC STRUCTURE OF DIFFERENT AGE GROUPS OF SILVER (HYPOPHTHALMICHTHYS MOLITRIX) AND BIGHEAD (ARISTICHTHYS NOBILIS) CARPS FROM FISH FARM LIMANSKE

    OpenAIRE

    Т. Nagorniuk; I. Hrytsyniak; N. Borysenko

    2015-01-01

    Purpose. Studying the peculiarities of the genetic structure of different age groups of silver and bighead carps from fish farm Limanske with the use of genetic-biochemical markers. Methodology. The methods of vertical polyacrylamide and horizontal starch electrophoresis with our own modifications have been used for the study. Sampling of the biological material and histochemical staining of gel plates were carried out using the generally accepted methods. Statistical analysis of the obta...

  10. Nematodes as indicators of shrimp farm impact on an amazonian estuary (Curuçá, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Virag Venekey

    2016-03-01

    Full Text Available Abstract Shrimp farming reduces demand on wild fishery stocks and avoids environmental damage resulting from fishing practices, however, it has the potential to affect the water quality if not properly managed. In this study the impacts of a shrimp farm in an Amazonian estuary were evaluated, focusing on changes in nematodes regarding taxonomic composition, richness, density and diversity. Sampling was conducted in August 2004 (dry season and January 2005 (rainy season in the river at stations situated upstream and downstream at different distances from the main source of farm effluent discharge. Thirty-eight genera were recorded with Terschellingia dominating in the dry season and Terschellingia, Daptonema, Ptycholaimellus and Gomphionema in the rainy season. Abundances were within the range recorded in other estuaries and together with genera richness and diversity showed a strong temporal pattern with significantly higher values in the rainy season. No clear patterns of changes were observed at the stations. Some signs of organic enrichment were detected but they were not yet intense, probably a consequence of the strong local hydrodynamics and the age of the shrimp farm, which was just starting its operation. We recommend that in future studies on farming impacts a combination of factors, beyond the physical and chemical parameters of the water and sediments or taxonomic refinement, should be taken into account - such as the duration of the operation of the farm, the area occupied by ponds and the farm's production. Furthermore, we also believe that nematodes are a useful tool for evaluating aquaculture impacts due to the ease of sampling and because they are organisms at the base of marine food chain.

  11. A Study of Fish Lice (Argulus Sp. Infection in Freshwater Food Fish

    Directory of Open Access Journals (Sweden)

    Aalberg K.

    2016-09-01

    Full Text Available Argulus sp., commonly referred to as fish lice, are crustacean ectoparasites of fishes. The hematophagous parasites attach to and feed off the integument of their hosts. Outbreaks of epizootics have been reported worldwide, causing mass mortalities and having serious economic implications for fish farms and culture efforts. Argulus fish lice may also serve as vectors of infectious diseases and as intermediate hosts of other parasites. Two native European species, A. foliaceus and A. coregoni, as well as the invasive Japanese fish louse A. japonicus, have previously been recorded in Slovakia. This study investigated samples collected at fish farms and culture sites of Common carp (Cyprinus carpio L., Pike-perch (Sander lucioperca L. and Brook trout (Salvelinus fontinalis M. in Eastern Slovakia, as well as samples collected from live fish imported to the Slovak Republic. A quantitative description of the of Argulus sp. was recorded from each locality. Samples from Common carp were identified as the invasive A. japonicus, and samples from Pike-perch and Brook trout were identified as A. foliaceus. Evidence of a mixed infection of Pike-perch with both A. foliaceus and A. japonicus was found in samples from Zemplínska Šírava, which was substantiated by electron microscopic examination. Morphometric characteristics were measured and averages and ranges produced for each species and sex.

  12. Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

    DEFF Research Database (Denmark)

    Apostolaki, E; Holmer, Marianne; Marbà, N

    2011-01-01

    We studied the relationship between sediment nutrient enrichment and carbon sequestration, using the ratio of gross primary production to respiration (P/R), in a fish-farming impacted and an unaffected Mediterranean seagrass (Posidonia oceanica) ecosystem in the Aegean Sea, Greece. Carbon (C......), nitrogen (N) and phosphorus (P) sedimentation, nutrient pools in sediment and dissolved nutrients in pore water were significantly and positively intercorrelated, indicating close linkage between sedimentation and sediment nutrient pools in seagrass meadows. C, N and P sediment pools were significantly...... nutrient enrichment. Threshold values are given for C, N and P sedimentation rates and sediment pools, and for N and P concentrations in pore waters, after which P/R ratio in the seagrass meadow decreases below 1, indicating a shift from autotrophy to heterotrophy with sediment nutrient enrichment...

  13. Anadromous fish behaviour important for fish passage

    International Nuclear Information System (INIS)

    Kynard, B.E.

    1993-01-01

    An understanding of the behavior of target fish species is necessary for proper design, location, and operation of a successful upstream or downstream fishway for anadromous migrants. Important fish behaviors are seasonal and daily timing of migration; rheotaxis and near field behavior; stimulus-response behavior; swimming capability; shoaling behavior; response to physical environmental factors such as illumination, sound, water depth, current velocity, and structure; response to chemicals; and response to biological factors such as competition for space and response to predators. The information on migrant fish behavior is reviewed, using examples from the literature on the behavior of eastern anadromous species, particularly Atlantic salmon (Salmo salar) and American shad (Alosa sapidissima). 87 refs

  14. Analyzing Broadband Divide in the Farming Sector

    DEFF Research Database (Denmark)

    Jensen, Michael; Gutierrez Lopez, Jose Manuel; Pedersen, Jens Myrup

    2013-01-01

    , upstream and downstream connection. The main constraint is that farms are naturally located in rural areas where the required access broadband data rates are not available. This paper studies the broadband divide in relation to the Danish agricultural sector. Results show how there is an important......Agriculture industry has been evolving for centuries. Currently, the technological development of Internet oriented farming tools allows to increase the productivity and efficiency of this sector. Many of the already available tools and applications require high bandwidth in both directions...... difference between the broadband availability for farms and the rest of the households/buildings the country. This divide may be slowing down the potential technological development of the farming industry, in order to keep their competitiveness in the market. Therefore, broadband development in rural areas...

  15. Modeling Parasite Dynamics on Farmed Salmon for Precautionary Conservation Management of Wild Salmon

    Science.gov (United States)

    Rogers, Luke A.; Peacock, Stephanie J.; McKenzie, Peter; DeDominicis, Sharon; Jones, Simon R. M.; Chandler, Peter; Foreman, Michael G. G.; Revie, Crawford W.; Krkošek, Martin

    2013-01-01

    Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March–June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions. PMID:23577082

  16. Modeling parasite dynamics on farmed salmon for precautionary conservation management of wild salmon.

    Directory of Open Access Journals (Sweden)

    Luke A Rogers

    Full Text Available Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis on domesticated populations of Atlantic salmon (Salmo salar in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity, local host density (measured as cohort surface area, and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp. migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions.

  17. Relação parasito-hospedeiro em peixes de pisciculturas da região de Assis, Estado de São Paulo, Brasil. 2. Piaractus mesopotamicus (Holmberg, 1887 = Host-parasite relationship of fishes from fish farm in Assis region, São Paulo State, Brazil. 2. Piaractus mesopotamicus (Holmberg, 1887

    Directory of Open Access Journals (Sweden)

    Maria de los Angeles Perez Lizama

    2007-10-01

    Full Text Available Piaractus mesopotamicus (Holmberg, 1887 é uma das espécies nativas mais difundidas em pisciculturas no Brasil. Este estudo foi realizado em três pisciculturas do Estado de São Paulo, durante os meses de fevereiro a dezembro de 2004. Oitenta e três espécimes (92,2% estavamparasitados por pelo menos uma espécie de parasito. Oito espécies de ectoparasitos foram registradas. Anacanthorus penilabiatus, A. spatulathus e Mymarothecium sp. 2 foram classificadas como centrais, e Mymarothecium sp. 1, secundária. As demais foram consideradas satélites. Foi possível evidenciar que, apesar de as espécies serem altamente prevalentes, poucas delas foram abundantes. Anacanthorus penilabiatus apresentou correlação negativa e significativa entre a abundância de parasitismo e o comprimento-padrão do hospedeiro, na propriedade do município de Tarumã, Estado de São Paulo. Mymarothecium sp. 2 apresentou correlação positiva significativa na piscicultura de Cândido Mota, Estado de São Paulo. Neste estudo, os resultados do fator de condição relativo demonstram que somente na propriedade de Palmital, Estado de São Paulo, ocorreu correlaçãosignificativa entre o Kn e a abundância de parasitismo para algumas espécies. Anacanthorus penilabiatus e A. spatulathus apresentaram-se correlacionadas positivamente com a relação hepatossomática naspisciculturas dos municípios de Tarumã e Cândido Mota, Estado de São Paulo. Em se tratando da relação esplenossomática, somente a espécie de ergasilídeo apresentou-se negativa e significativamente correlacionada em Cândido Mota, Estado de São Paulo.Piaractus mesopotamicus (Holmberg, 1887 is one of the most abundant native species in fish farmings in Brazil. This study was conducted in three fish farmings in São Paulo State, during February and December, 2004. Eighty-three specimens (92.2% were parasitized by at least one parasite species. Eight species of ectoparasites were registered

  18. Environmental radiological studies downstream from Rancho Seco Nuclear Power Generating Station

    International Nuclear Information System (INIS)

    Noshkin, V.E.; Wong, K.M.; Eagle, R.J.; Dawson, J.W.; Brunk, J.L.; Jokela, T.A.

    1985-01-01

    This report summarizes the information compiled in 1984 while assessing the environmental impact of radionuclides in aquatic releases from the Rancho Seco Nuclear Power Generating Station. Gamma-emitting radionuclides discharged since 1981 are found in many of the dietary components derived from the creeks receiving the effluent wastewater. Some soils and crops are found to contain radionuclides that originate from the contaminated water that was transferred to land during the irrigation season. 134 Cs and 137 Cs are the primary gamma-emitting radionuclides detected in the edible flesh of fish from the creeks. Concentrations in the flesh of fish decreased exponentially with distance from the plant. No significant differences in the 137 Cs activity were found between male and female fish of equal size, but concentrations may vary in fish of different size, with the season and diet. 21% of the total 137 Cs and 134 Cs discharged between 1981 and 1984 is associated with the creek sediments to a distance of 27 km from the plant. Fractions of the missing inventory have been transferred to land during the irrigation season or to downstream regions more distant than 27 km from the plant. The radiocesium content of the sediments in 1984 decreased significantly in a downstream direction, much in the same manner as concentrations decreased in fish. Radioactivity originating from the plant was not above detection limits in any terrestrial food item sampled beyond 6.5 km from the plant. Based on the usage factors provided by individuals interviewed in a 1984 survey, the fish and aquatic-organism ingestion pathway contributed the largest radiological dose to humans utilizing products contaminated with the radionuclides in the liquid wastes discharged from the Rancho Seco Nuclear Power Generating Station in 1984

  19. Small larvae in large rivers: observations on downstream movement of European grayling Thymallus thymallus during early life stages.

    Science.gov (United States)

    Van Leeuwen, C H A; Dokk, T; Haugen, T O; Kiffney, P M; Museth, J

    2017-06-01

    Behaviour of early life stages of the salmonid European grayling Thymallus thymallus was investigated by assessing the timing of larval downstream movement from spawning areas, the depth at which larvae moved and the distribution of juvenile fish during summer in two large connected river systems in Norway. Trapping of larvae moving downstream and electrofishing surveys revealed that T. thymallus larvae emerging from the spawning gravel moved downstream predominantly during the night, despite light levels sufficient for orientation in the high-latitude study area. Larvae moved in the water mostly at the bottom layer close to the substratum, while drifting debris was caught in all layers of the water column. Few young-of-the-year still resided close to the spawning areas in autumn, suggesting large-scale movement (several km). Together, these observations show that there may be a deliberate, active component to downstream movement of T. thymallus during early life stages. This research signifies the importance of longitudinal connectivity for T. thymallus in Nordic large river systems. Human alterations of flow regimes and the construction of reservoirs for hydropower may not only affect the movement of adult fish, but may already interfere with active movement behaviour of fish during early life stages. © 2017 The Fisheries Society of the British Isles.

  20. Prevalence and location of Listeria monocytogenes in farmed rainbow trout.

    Science.gov (United States)

    Miettinen, Hanna; Wirtanen, Gun

    2005-10-15

    A total of 510 rainbow trout originating from fish farms in lakes and sea areas around Finland were studied for the presence of Listeria monocytogenes. Samples were studied as pools from five fish. Gill, viscera, and skin from the pooled samples were analysed separately. The individual samples were analysed later if the pooled sample was found to be Listeria positive. The prevalence of Listeria spp. and L. monocytogenes in pooled unprocessed fresh rainbow trout was on average 35.0% and 14.6%, respectively. On the other hand, the prevalence of Listeria spp. and L. monocytogenes in individual thawed fish was found to be 14.3% and 8.8%, respectively. These numbers tend to overestimate and underestimate the real situation because not all fish in pooled samples were necessarily contaminated and in some of the Listeria positive pooled samples all individual samples turned out to be Listeria free. The prevalence of L. monocytogenes varied greatly between different fish farms from zero to 100% in pooled samples and from zero to 75% according to individually studied fish samples. Some indications of the influence of weather conditions and seasonal variations that strongly affected the Listeria contamination of fish were also noticed. The location of Listeria spp. and L. monocytogenes in different parts of the fish differed with statistical significance in rainbow trout. Up to 95.6% of the L. monocytogenes and 84.5% of Listeria spp. positive samples were gill samples. Only 4.4% (2/45) of the L. monocytogenes positive samples were obtained from skin or viscera. Closer study at one fish farm revealed that there was only one L. monocytogenes ribotype present in the contaminated fish, although water and surfaces were heavily contaminated with six other L. monocytogenes ribotypes.

  1. Total Mercury and Methylmercury Contamination in Fish from Sites along the Elbe River

    Directory of Open Access Journals (Sweden)

    P. Maršálek

    2006-01-01

    Full Text Available The aim of the study was to evaluate total mercury Hg and methylmercury MeHg contamination in muscle tissues of fish collected in 2002 from the Labe (Elbe river at sites upstream of Pardubice and downstream of Pardubice and Hřensko, and in 2004 from the Labe river upstream and downstream of the Spolana factory in Neratovice, and from the Vltava river downstream of Lenora. Eighty eight fish of the following species were sampled: bream (Abramis brama L., perch (Perca fluviatilis L., chub (Leuciscus cephalus L. and barbel (Barbus barbus L.. Total mercury content in chub, perch and bream was in the range of 0.05 - 1.96 mg kg-1 w.w., 0. 09 - 1.46 mg kg-1 w.w. and 0.35 - 0.82 mg kg-1 w.w., respectively. Methylmercury content in chub, perch and bream was in the range of 0.04 - 2.11 mg kg-1 w.w., 0.1 - 1.73 mg kg-1 w.w. and 0.371 - 0.650 mg kg-1 w.w., respectively. Significant correlation (p p < 0.05 between THg and MeHg contents were found between individual sites. In 2002, for example, the most contaminated fish were found downstream of Pardubice, followed by fish from upstream of Pardubice and from Hřensko. In 2004, fish from downstream and upstream of the Spolana factory in Neratovice were more contaminated than fish from the Vltava river downstream of Lenora. The methylmercury-tototal mercury ratio in muscle tissue was close to 1.0.

  2. Reducing Turbine Mechanical Loads Using Flow Model-Based Wind Farm Controller

    DEFF Research Database (Denmark)

    Kazda, Jonas; Cutululis, Nicolaos Antonio

    Cumulated O&M costs of offshore wind farms are comparable with wind turbine CAPEX of such wind farm. In wind farms, wake effects can result in up to 80% higher fatigue loads at downstream wind turbines [1] and consequently larger O&M costs. The present work therefore investigates to reduce...... these loads during the provision of grid balancing services using optimal model-based wind farm control. Wind farm controllers coordinate the operating point of wind turbines in a wind farm in order to achieve a given objective. The investigated objective of the control in this work is to follow a total wind...... farm power reference while reducing the tower bending moments of the turbines in the wind farm. The wind farm controller is tested on a 8 turbine array, which is representative of a typical offshore wind farm. The operation of the wind farm is simulated using the dynamic wind farm simulation tool S imWind...

  3. Survey of n-3 and n-6 polyunsaturated fatty acids in fish and fish products.

    Science.gov (United States)

    Strobel, Claudia; Jahreis, Gerhard; Kuhnt, Katrin

    2012-10-30

    The imbalance of the n-3/n-6 ratio in the Western diet is characterised by a low intake of n-3 long-chain (LC) PUFA and a concurrent high intake of n-6 PUFA. Fish, in particular marine fish, is a unique source of n-3 LC PUFA. However, FA composition of consumed fish changed, due to the increasing usage of n-6 PUFA-rich vegetable oils in aquaculture feed and in fish processing (frying) which both lead to a further shift in n-6 PUFA to the detriment of n-3 LC PUFA.The aim of this study was to determine the ratio of n-3/n-6 including the contents of EPA and DHA in fish fillets and fish products from the German market (n=123). Furthermore, the study focussed on the FA content in farmed salmon compared to wild salmon as well as in processed Alaska pollock fillet, e.g., fish fingers. Total fat and FA content in fish products varied considerably depending on fish species, feed management, and food processing. Mackerel, herring and trout fillets characteristically contained adequate dietary amounts of absolute EPA and DHA, due to their high fat contents. However, despite a lower fat content, tuna, pollock, and Alaska pollock can contribute considerable amounts of EPA and DHA to the human supply.Farmed salmon are an appropriate source of EPA and DHA owing to their higher fat content compared to wild salmon (12.3 vs. 2.1 wt %), however with elevated SFA, n-9 and n-6 FA contents representing the use of vegetable oils and oilseeds in aquaculture feed. The n-3/n-6 ratio was deteriorated (2.9 vs. 12.4) but still acceptable. Compared to pure fish fillets, breaded and pre-fried Alaska pollock fillet contained extraordinarily high fat and n-6 PUFA levels. Since fish species vary with respect to their n-3 LC PUFA contents, eating a variety of fish is advisable. High n-6 PUFA containing pre-fried fish support the imbalance of n-3/n-6 ratio in the Western diet. Thus, consumption of pure fish fillets is to be favoured. The lower n-3 PUFA portion in farmed fish can be offset by the

  4. Survey of n-3 and n-6 polyunsaturated fatty acids in fish and fish products

    Directory of Open Access Journals (Sweden)

    Strobel Claudia

    2012-10-01

    Full Text Available Abstract Background The imbalance of the n-3/n-6 ratio in the Western diet is characterised by a low intake of n-3 long-chain (LC PUFA and a concurrent high intake of n-6 PUFA. Fish, in particular marine fish, is a unique source of n-3 LC PUFA. However, FA composition of consumed fish changed, due to the increasing usage of n-6 PUFA-rich vegetable oils in aquaculture feed and in fish processing (frying which both lead to a further shift in n-6 PUFA to the detriment of n-3 LC PUFA. The aim of this study was to determine the ratio of n-3/n-6 including the contents of EPA and DHA in fish fillets and fish products from the German market (n=123. Furthermore, the study focussed on the FA content in farmed salmon compared to wild salmon as well as in processed Alaska pollock fillet, e.g., fish fingers. Results Total fat and FA content in fish products varied considerably depending on fish species, feed management, and food processing. Mackerel, herring and trout fillets characteristically contained adequate dietary amounts of absolute EPA and DHA, due to their high fat contents. However, despite a lower fat content, tuna, pollock, and Alaska pollock can contribute considerable amounts of EPA and DHA to the human supply. Farmed salmon are an appropriate source of EPA and DHA owing to their higher fat content compared to wild salmon (12.3 vs. 2.1 wt %, however with elevated SFA, n-9 and n-6 FA contents representing the use of vegetable oils and oilseeds in aquaculture feed. The n-3/n-6 ratio was deteriorated (2.9 vs. 12.4 but still acceptable. Compared to pure fish fillets, breaded and pre-fried Alaska pollock fillet contained extraordinarily high fat and n-6 PUFA levels. Conclusions Since fish species vary with respect to their n-3 LC PUFA contents, eating a variety of fish is advisable. High n-6 PUFA containing pre-fried fish support the imbalance of n-3/n-6 ratio in the Western diet. Thus, consumption of pure fish fillets is to be favoured. The lower

  5. Use of compositional analysis to distinguish farmed and wild gilthead seabream (Sparus aurata

    Directory of Open Access Journals (Sweden)

    F. Valfré

    2010-01-01

    Full Text Available Recent food scares have emphasized the need for traceability in the food chain. This is particularly true in the fish sector, where a large difference in the final price between wild and farmed fish and even between farmed fish reared in different countries exists. So for these commercial and hygienic reasons it is very important to find useful tools for the characterization of quality of fish and for the differentiation of fish from different production methods and from different countries, in accordance with EC Regulation No. 2065/2001 and Italian Ministry of Agriculture Decree No. 27.03.02, that allow retail trade of fishery and aquaculture products only against the indication of the official commercial name, the method of production and the geographical origin of fish (Moretti et al., 2003.

  6. In-operation learning of optimal wind farm operation strategy

    OpenAIRE

    Oliva Gratacós, Joan

    2017-01-01

    In a wind farm, power losses due to wind turbine wake effects can be up to 30-40% under certain conditions. As the global installed wind power capacity increases, the mitigation of wake effects in wind farms is gaining more importance. Following a conventional control strategy, each individual turbine maximizes its own power production without taking into consideration its effects on the performance of downstream turbines. Therefore, this control scheme results in operation con...

  7. PHYTOPLANKTON ASSEMBLAGES AT FISH FARM IN MASLINOVA BAY (THE ISLAND OF BRAČ

    Directory of Open Access Journals (Sweden)

    Sanda Skejić

    2012-07-01

    Full Text Available The aim of this study was to establish phytoplankton composition at the sea bream (Sparus aurata and sea bass (Dicentrarchus labrax fish farm in the middle Adriatic Sea. The investigation was performed from September 2005 to September 2006 at a station located in Maslinova Bay at the island of Brač. Considering the whole research period, diatoms generally prevailed in terms of abundance while dinoflagellates were particularly abundant in June. Number of species of diatoms in comparison to dinoflagellates through the investigated period was similar. From 111 species of phytoplankton found, there were 55 species of Bacillariophyceae (diatoms, 47 species of Dinophyta (dinoflagellates, 5 species of Prymnesiophyceae, 3 Chrysophyceae and 1 Euglenophyta. Among the diatoms, the majority of species belonged to genus Chaetoceros. The most represented dinoflagellate genera were Oxytoxum and Gymnodinium. There were no considerable differences in phytoplankton composition with respect to different depths, but seasonal influence was significant. Biodiversity and abundance ranges of phytoplankton species indicated good water conditions and there were no evident alterations induced by the increased release of nutrients.

  8. Pulsed-field gel electrophoresis and multi locus sequence typing for characterizing genotype variability of Yersinia ruckeri isolated from farmed fish in France.

    Science.gov (United States)

    Calvez, Ségolène; Fournel, Catherine; Douet, Diane-Gaëlle; Daniel, Patrick

    2015-06-23

    Yersinia ruckeri is a pathogen that has an impact on aquaculture worldwide. The disease caused by this bacterial species, yersiniosis or redmouth disease, generates substantial economic losses due to the associated mortality and veterinary costs. For predicting outbreaks and improving control strategies, it is important to characterize the population structure of the bacteria. The phenotypic and genetic homogeneities described previously indicate a clonal population structure as observed in other fish bacteria. In this study, the pulsed-field gel electrophoresis (PFGE) and multi locus sequence typing (MLST) methods were used to describe a population of isolates from outbreaks on French fish farms. For the PFGE analysis, two enzymes (NotI and AscI) were used separately and together. Results from combining the enzymes showed the great homogeneity of the outbreak population with a similarity > 80.0% but a high variability within the cluster (cut-off value = 80.0%) with a total of 43 pulsotypes described and an index of diversity = 0.93. The dominant pulsotypes described with NotI (PtN4 and PtN7) have already been described in other European countries (Finland, Germany, Denmark, Spain and Italy). The MLST approach showed two dominant sequence types (ST31 and ST36), an epidemic structure of the French Y. ruckeri population and a preferentially clonal evolution for rainbow trout isolates. Our results point to multiple types of selection pressure on the Y. ruckeri population attributable to geographical origin, ecological niche specialization and movements of farmed fish.

  9. Preliminary studies in rice-fish culture in a rainfed lowland ecology ...

    African Journals Online (AJOL)

    Mixed farms of rice and fish are yet to receive attention in Ghana, despite lowland rice being grown under inundation in most areas nationwide. In a preliminary study, Nile tilapia (Oreochromis niloticus) was successfully cultured in a rainfed lowland rice farm, although no additional care was provided for fishes. The highest ...

  10. Fish Farmers' Perception of Climate change impact on fish ...

    African Journals Online (AJOL)

    Michael Madukwe

    *Department of Agricultural Extension and Management ... Respondents in the area perceived climate change factors ... rural farmers who implement their regular annual farm business plans risk total ... 2010). Constraints to increased fish production in Nigeria include, among others, ..... Build ponds close to water sources.

  11. Heart and skeletal muscle inflammation (HSMI disease diagnosed on a British Columbia salmon farm through a longitudinal farm study.

    Directory of Open Access Journals (Sweden)

    Emiliano Di Cicco

    Full Text Available Heart and skeletal muscle inflammation (HSMI is an emerging disease of marine-farmed Atlantic Salmon (Salmo salar, first recognized in 1999 in Norway, and later also reported in Scotland and Chile. We undertook a longitudinal study involving health evaluation over an entire marine production cycle on one salmon farm in British Columbia (Canada. In previous production cycles at this farm site and others in the vicinity, cardiac lesions not linked to a specific infectious agent or disease were identified. Histologic assessments of both live and moribund fish samples collected at the farm during the longitudinal study documented at the population level the development, peak, and recovery phases of HSMI. The fish underwent histopathological evaluation of all tissues, Twort's Gram staining, immunohistochemistry, and molecular quantification in heart tissue of 44 agents known or suspected to cause disease in salmon. Our analysis showed evidence of HSMI histopathological lesions over an 11-month timespan, with the prevalence of lesions peaking at 80-100% in sampled fish, despite mild clinical signs with no associated elevation in mortalities reported at the farm level. Diffuse mononuclear inflammation and myodegeneration, consistent with HSMI, was the predominant histologic observation in affected heart and skeletal muscle. Infective agent monitoring identified three agents at high prevalence in salmon heart tissue, including Piscine orthoreovirus (PRV, and parasites Paranucleospora theridion and Kudoa thyrsites. However, PRV alone was statistically correlated with the occurrence and severity of histopathological lesions in the heart. Immunohistochemical staining further localized PRV throughout HSMI development, with the virus found mainly within red blood cells in early cases, moving into the cardiomyocytes within or, more often, on the periphery of the inflammatory reaction during the peak disease, and reducing to low or undetectable levels later in

  12. Sensitivity of the downward to sweeping velocity ratio to the bypass flow percentage along a guide wall for downstream fish passage

    Science.gov (United States)

    Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

    2017-01-01

    Partial-depth impermeable guidance structures (or guide walls) are used as a method to assist in the downstream passage of fish at a hydroelectric facility. However, guide walls can result in a strong downward velocity causing the approaching fish to pass below the wall and into the direction of the turbine intakes. The objective of this study was to describe how the ratio of the vertical velocity to the sweeping velocity magnitude changes along the full length and depth of a guide wall under a wide range of bypass flow percentages within a power canal. This paper focused on two guide wall configurations, each set at an angle of 45 ° to the approaching flow field and at a depth of 10 and 20 ft (3.05 and 6.10 m). The hydraulic conditions upstream of each guide wall configuration were shown to be impacted by a change in the bypass flow percentage, not only near the bypass but also at upstream sections of the guide wall. Furthermore, the effect of changing the bypass flow percentage was similar for both guide wall depths. In both cases, the effect of increasing the bypass flow percentage was magnified closer to the bypass and deeper in the water column along the guide wall.

  13. Depletion of selected polychlorodibenzodioxins and polychlorodibenzofurans in farmed trout exposed to contaminated feeds

    Energy Technology Data Exchange (ETDEWEB)

    Brambilla, G.; Dellatte, E.; Fochi, I.; Iacovella, N.; Domenico, A. di [Dept. Food Safety and Animal Health, Ist. Superiore di Sanita, Rome (Italy)]|[Dept. Environment and Primary Health Care, Ist. Superiore di Sanita, Rome (Italy)

    2004-09-15

    Farmed fish can bioaccumulate persistent toxic substances when fed on animal-based fat feeds. This fact has recently prompted a re-evaluation of the overall toxicological risk associated with contamination levels recorded in farmed vs. wild salmons. The bioaccumulation of polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) in farmed trout has recently been described nevertheless, poor information is available about their depletion under controlled conditions. In this paper, the results of a 90-day depletion study in groups of trout exposed to three different levels of feed contamination for 30 days are reported. As a follow-up of a PCB depletion study the present paper aims at giving indications for risk management in fish farming practices, to prevent an unacceptable contamination of the produce intended for human consumption.

  14. Copepoda parasites in economically important fish, Mugilidae ...

    African Journals Online (AJOL)

    FUNMILAYO

    of economically important fish, both from the wild and fish farms, thus making them difficult to market. In this study ... Sakiti, 1997; Gbankoto et al., 2003) but no work has been carried out on ... digital weighing balance and recorded. ..... Life Sci. J. 9(3):733-737. Paperna I, Lahav M (1971). New records and further data on fish.

  15. Global assessment of polybrominated diphenyl ethers in farmed and wild salmom

    Energy Technology Data Exchange (ETDEWEB)

    Hites, R. [Indiana Univ., Bloomington, IN (United States); Foran, J. [Midwest Center for Environmental Science, Milwaukee, WI (United States); Schwager, S.; Knuth, B. [Cornell Univ., Ithaca, NY (United States); Hamilton, C. [AXYS Analytical, Sydney (Australia); Carpenter, D. [Albany Univ., NY (United States)

    2004-09-15

    Despite their societal benefits, polybrominated diphenyl ethers (PBDEs) seem to be migrating from the products in which they are used and entering the environment and people. PBDEs are now ubiquitous; they can be found in air, water, fish, birds, marine mammals, and people, and in most cases, the concentrations of these compounds have increased dramatically over the last 20 years. One source of PBDEs in people is their food supply, and an increasingly important food is salmon, which is nutritious and high in beneficial fats. Between 1987 and 1999, salmon consumption increased annually at a rate of 10-20%. Currently, over half the salmon sold globally is farm-raised in Northern Europe, Chile, Canada, and the United States, and the annual global production of farmed salmon (predominantly Atlantic salmon) has risen from {proportional_to}27,000 to over 1 million metric tons during the past two decades. The health benefits of eating fish such as salmon have been well documented. However, salmon are relatively fatty, carnivorous fish that feed high in the food web, and as such, they bioaccumulate contaminants. In a previous study, we reported that levels of persistent, bioaccumulative contaminants (such as PCBs, dioxins, and several chlorinated pesticides) are significantly higher in farm-raised salmon than in wild salmon and that salmon raised on European farms have significantly greater toxic contaminant loads than those raised on North and South American farms. In this report, we provide results on polybrominated diphenyl ether concentrations in salmon purchased from farms in eight major salmon farming regions, in five species of wild Pacific salmon, and in salmon fillets purchased at supermarkets in North America and Europe.

  16. Tissue distribution of organochlorine pesticides in fish collected from the Pearl River Delta, China: Implications for fishery input source and bioaccumulation

    International Nuclear Information System (INIS)

    Guo Ying; Meng Xiangzhou; Tang Honglei; Zeng, Eddy Y.

    2008-01-01

    Fish tissues from different fishery types (freshwater farmed, seawater farmed and seawater wild) were analyzed for organochlorine pesticides (OCPs), with the aim to further our understanding of bioaccumulation, and reflect the state of different fishery environments. Significantly higher ΣOCP levels were found in seawater farmed fish than others, and among three freshwater farmed species, the lowest levels occurred in filter-feeding fish (bighead carp). Liver contained the highest ΣOCP levels, while no significant differences were found among other tissues. Among DDT components, p,p'-DDT was abundant in seawater fish, while for freshwater fish, p,p'-DDE was the predominant congeners, except for northern snakehead (34% for p,p'-DDE and 30% for p,p'-DDT). The new source of DDTs to freshwater fish ponds was partly attributed to dicofol, whereas sewage discharged from the Pearl River Delta and anti-fouling paint were likely the DDTs sources to seawater farmed fish. - Occurrence of organochlorine pesticides in fish tissues was examined to assess input sources and modes of bioaccumulation in the Pearl River Delta, China

  17. Business plan Tilapia cage farming in Tete Zambezi Valley, Mozambique

    NARCIS (Netherlands)

    Meer, van der Magnus; Brouwer, Herman

    2015-01-01

    Tete province offers great opportunities for cage farming of tilapia in Lake Cahora Bassa. The climate and water quality are favourable for fish production, and the fast economic developments in the region will facilitate fish sales. In Tete tilapia (pende) is highly valued food. Major markets for

  18. Marine Model Trout Farms: developments in marine RAS

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg

    2011-01-01

    , nitrogen is removed in a full-scale experimental set-up where sludge from the drum filter is hydrolysed and the VFAs generated used as energy-source for the denitrification process in separate tanks/filters. Final polishing follows in a constructed wetland. For the first 2 years of operation production......Economical and environmentally sustainable production of large salmonids in sea water has in Denmark been called for during some years. Based on the experience gained from the Danish Model Trout Farms in freshwater, a rather similar concept has been developed for farming of larger fish in sea water...... temperature the pumps can be individually turned on/off primarily in relation to oxygen need and consumption in the fish tank. In a 1 year batch production some 20 t of fish will be introduced in April and some 80 t are supposed to be harvested in December. End-of-pipe treatment is a two-step process. First...

  19. A Framework Based on a Systems Approach to Developing Safety Indicators in Fish Farming

    Directory of Open Access Journals (Sweden)

    Siri Mariane Holen

    2018-05-01

    Full Text Available The fish farming industry is one of the industries in Norway with the highest occupational fatality and injury rate. Despite the serious health, safety, and environmental issues in the industry, little is done to measure changes in safety over time beyond the traditional Lost Time Injury (LTI registrations. In this article the objective is twofold; (i to propose a framework for developing safety indicators based on Systems-Theoretic Process Analysis (STPA, and (ii to apply the framework to find indicators relevant for hazards in operations where subcontractors participate. STPA uses a hierarchical portrayal of the system in focus, in contrast to sequential models, and views safety as a control problem. It is believed that a systemic approach to indicator development better captures the complex safety challenges in aquaculture. Thirteen indicators are identified within areas such as maintenance, training, and planning. The indicators identified may function as a basis for decisions and actions that must be undertaken to ensure safe operations.

  20. Use of food waste, fish waste and food processing waste for China's aquaculture industry: Needs and challenge.

    Science.gov (United States)

    Mo, Wing Yin; Man, Yu Bon; Wong, Ming Hung

    2018-02-01

    China's aquaculture industry is growing dramatically in recent years and now accounts for 60.5% of global aquaculture production. Fish protein is expected to play an important role in China's food security. Formulated feed has become the main diet of farmed fish. The species farmed have been diversified, and a large amount of 'trash fish' is directly used as feed or is processed into fishmeal for fish feed. The use of locally available food waste as an alternative protein source for producing fish feed has been suggested as a means of tackling the problem of sourcing safe and sustainable feed. This paper reviews the feasibility of using locally available waste materials, including fish waste, okara and food waste. Although the fishmeal derived from fish waste, okara or food waste is less nutritious than fishmeal from whole fish or soybean meal, most fish species farmed in China, such as tilapia and various Chinese carp, grow well on diets with minimal amounts of fishmeal and 40% digestible carbohydrate. It can be concluded that food waste is suitable as a component of the diet of farmed fish. However, it will be necessary to revise regulations on feed and feed ingredients to facilitate the use of food waste in the manufacture of fish feed. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. How many fish in a tank? Constructing an automated fish counting system by using PTV analysis

    Science.gov (United States)

    Abe, S.; Takagi, T.; Takehara, K.; Kimura, N.; Hiraishi, T.; Komeyama, K.; Torisawa, S.; Asaumi, S.

    2017-02-01

    Because escape from a net cage and mortality are constant problems in fish farming, health control and management of facilities are important in aquaculture. In particular, the development of an accurate fish counting system has been strongly desired for the Pacific Bluefin tuna farming industry owing to the high market value of these fish. The current fish counting method, which involves human counting, results in poor accuracy; moreover, the method is cumbersome because the aquaculture net cage is so large that fish can only be counted when they move to another net cage. Therefore, we have developed an automated fish counting system by applying particle tracking velocimetry (PTV) analysis to a shoal of swimming fish inside a net cage. In essence, we treated the swimming fish as tracer particles and estimated the number of fish by analyzing the corresponding motion vectors. The proposed fish counting system comprises two main components: image processing and motion analysis, where the image-processing component abstracts the foreground and the motion analysis component traces the individual's motion. In this study, we developed a Region Extraction and Centroid Computation (RECC) method and a Kalman filter and Chi-square (KC) test for the two main components. To evaluate the efficiency of our method, we constructed a closed system, placed an underwater video camera with a spherical curved lens at the bottom of the tank, and recorded a 360° view of a swimming school of Japanese rice fish (Oryzias latipes). Our study showed that almost all fish could be abstracted by the RECC method and the motion vectors could be calculated by the KC test. The recognition rate was approximately 90% when more than 180 individuals were observed within the frame of the video camera. These results suggest that the presented method has potential application as a fish counting system for industrial aquaculture.

  2. THE STATE OF ICHTHYOFAUNA IN THE BAY OF THE KIEV RESERVOIR EXPLOITED UNDER THE REGIME OF THE COMMODITY FISH FARM

    Directory of Open Access Journals (Sweden)

    I. Buzevich

    2014-12-01

    Full Text Available Purpose. Assessment of the number, stock, and major biological indices of the representatives of commercial ichthyofauna in the liman commodity fish farm created on the Kуiv reservoir. Methodology. The work is based on the ichthyologic material obtained from gill net catches with mesh size of 30-120 mm during the summer period of 2013. Data collection and processing were performed according to generally accepted methods. In total, catches of 169 net-days of control nets were analyzed, of which 3426 fish were collected. Quantitative parameters were assessed based on empirical relationships «number – catch-per-unit-effort of gill nets». Findings. Fifteen representatives of commercial ichthyofauna were observed in the bay, which is a cut-off part of the Kуiv reservoir. The majority in small mesh size nets were silver bream Blicca bjoerkna (45.5% in number and Prussian carp Carassius gibelio (24.6%. In large mesh size nets, 65.8% of catches in number and 86.1% by weight composed the introduced species – silver (Hypophthalmichthys molitrix, bighead (Aristichthys nobilis, and common carps (Cyprinus carpio. The native fish fauna of the bay was characterized by sufficiently high portion of commercially valuable fish species that indicates on a possibility for organizing an intensive harvest of the formed stock of the introduced species with high degree of selectivity. Length-weight indices of major commercial species are on the level, which is sufficient for normal fish productivity. Total commercial stocks of native ichthyofauna in the liman is 146 kg/ha that is three times higher than this value for the Kiev reservoir. Originality. For the first time, we performed a complex assessment of the ichthyofauna in the bay of a large reservoir, which for a long time has been used for stocking and intensive fish harvest. Practical value. Sound fish ranching has been shown to provide the stability of structural functional indices of the native

  3. Chemical and biochemical tools to assess pollution exposure in cultured fish

    International Nuclear Information System (INIS)

    Fernandes, Denise; Zanuy, Silvia; Bebianno, Maria Joao; Porte, Cinta

    2008-01-01

    There is little information regarding pollutant levels in farmed fish, and the risks associated to consumption. This study was designed to assess levels of exposure to metals, organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) in farmed sea bass Dicentrarchus labrax from five aquacultures located in Southern Europe. Additionally, several biochemical responses (metallothionein, 7-ethoxyresorufin O-deethylase, vitellogenin) were determined as complementary tools. The obtained data indicate that pollutants exposure in farmed fish is similar to the levels reported in wild specimens from the area. Nonetheless, some biochemical responses were observed in the studied organisms, viz. metallothionein induction in Cu exposed organisms, and 7-ethoxyresorufin O-deethylase (EROD) and vitellogenin induction in PAHs and APEs exposed ones. The study further supports the usefulness of the biomarker approach as a first screening method to discriminate between basal and high levels of exposure in cultured fish. - Pollution assessment in cultured fish: chemical and biochemical tools

  4. Polychlorinated Biphenyls (PCBs) in Catfish and Carp Collected from the Rio Grande Upstream and Downstream of Los Alamos National Laboratory: Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert J. Gonzales

    2008-05-12

    Concern has existed for years that the Los Alamos National Laboratory (LANL), a complex of nuclear weapons research and support facilities, has released polychlorinated biphenyls (PCBs) to the environment that may have reached adjacent bodies of water through canyons that connect them. In 1997, LANL's Ecology Group began measuring PCBs in fish in the Rio Grande upstream and downstream of ephemeral streams that cross LANL and later began sampling fish in Abiquiu and Cochiti reservoirs, which are situated on the Rio Chama and Rio Grande upstream and downstream of LANL, respectively. In 2002, we electroshocked channel catfish (Ictalurus punctatus) and common carp (Carpiodes carpio) in the Rio Grande upstream and downstream of LANL and analyzed fillets for PCB congeners. We also sampled soils along the Rio Chama and Rio Grande drainages to discern whether a background atmospheric source of PCBs that could impact surface water adjacent to LANL might exist. Trace concentrations of PCBs measured in soil (mean = 4.7E-05 {micro}g/g-ww) appear to be from background global atmospheric sources, at least in part, because the bimodal distribution of low-chlorinated PCB congeners and mid-chlorinated PCB congeners in the soil samples is interpreted to be typical of volatilized PCB congeners that are found in the atmosphere and dust from global fallout. Upstream catfish (n = 5) contained statistically (P = 0.047) higher concentrations of total PCBs (mean = 2.80E-02 {micro}g/g-ww) than downstream catfish (n = 10) (mean = 1.50E-02 {micro}g/g-ww). Similarly, upstream carp (n = 4) contained higher concentrations of total PCBs (mean = 7.98E-02 {micro}g/g-ww) than downstream carp (n = 4) (3.07E-02 {micro}g/g-ww); however, the difference was not statistically significant (P = 0.42). The dominant PCB homologue in all fish samples was hexachlorobiphenyls. Total PCB concentrations in fish in 2002 are lower than 1997; however, differences in analytical methods and other uncertainties

  5. Current status of parasitic ciliates Chilodonella spp. (Phyllopharyngea: Chilodonellidae) in freshwater fish aquaculture.

    Science.gov (United States)

    Bastos Gomes, G; Jerry, D R; Miller, T L; Hutson, K S

    2017-05-01

    Freshwater fish farming contributes to more than two-thirds of global aquaculture production. Parasitic ciliates are one of the largest causes of production loss in freshwater farmed fishes, with species from the genus Chilodonella being particularly problematic. While Chilodonella spp. include 'free-living' fauna, some species are involved in mortality events of fish, particularly in high-density aquaculture. Indeed, chilodonellosis causes major productivity losses in over 16 species of farmed freshwater fishes in more than 14 countries. Traditionally, Chilodonella species are identified based on morphological features; however, the genus comprises yet uncharacterized cryptic species, which indicates the necessity for molecular diagnostic methods. This review synthesizes current knowledge on the biology, ecology and geographic distribution of harmful Chilodonella spp. and examines pathological signs, diagnostic methods and treatments. Recent advances in molecular diagnostics and the ability to culture Chilodonella spp. in vitro will enable the development of preventative management practices and sustained freshwater fish aquaculture production. © 2016 John Wiley & Sons Ltd.

  6. Do intracoelomic telemetry transmitters alter the post-release behaviour of migratory fish?

    Science.gov (United States)

    Wilson, Alexander D.M.; Hayden, Todd A.; Vandergoot, Christopher S.; Kraus, Richard T.; Dettmers, John M.; Cooke, Steven J.; Charles C. Krueger,

    2016-01-01

    Electronic tags have become a common tool in fish research, enhancing our understanding of how fish interact with their environment and move among different habitats, for estimating mortality and recording internal physiological states. An often-untested assumption of electronic tagging studies is that tagged fish are representative of untagged conspecifics and thus show ‘normal’ behaviour (e.g. movement rates, swimming activity, feeding). Here, we use a unique data set for potamadromous walleye (Sander vitreus) in Lake Huron and Lake Erie tributaries to assess whether the lack of appropriate controls in electronic tagging could seriously affect behavioural data. We used fish tagged in previous years and compared their migratory behaviour during the spawning season to fish tagged in a current year at the same location. The objective of the study was to determine whether intracoelomic acoustic tag implantation altered downstream movement of walleye after spawning. Fish tagged in a given season travelled slower downstream from two river spawning sites than fish tagged in previous years. Fish tagged one or two years earlier showed no differences between each other in downstream travel time, in contrast to fish tagged in a given year. Our results support notions that standard collection and intracoelomic tagging procedures can alter short-term behaviour (i.e. days, weeks, months), and as such, researchers should use caution when interpreting data collected over such time periods. Further, whenever possible, researchers should also explicitly evaluate post-tagging effects on behaviour as part of their experimental objectives.

  7. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone. A compilation

    Energy Technology Data Exchange (ETDEWEB)

    Lindeboom, H.J.; Brasseur, S.; Leopold, M.; Scheidat, M. [IMARES, PO Box 167, 1790 AD Den Burg (Netherlands); Kouwenhoven, H.J. [NoordzeeWind, 2e Havenstraat 5b, 1976 CE IJmuiden (Netherlands); Bergman, M.J.N.; Daan, R. [Royal NIOZ, PO Box 59, 1790 AB Den Burg (Netherlands); Bouma, S.; Fijn, R.C.; Dirksen, S.; Krijgsveld, K.L. [Bureau Waardenburg, PO Box 365, 4100 AJ Culemborg (Netherlands); De Haan, D.; Van Hal, R.; Hille Ris Lambers, R.; Ter Hofstede, R. [IMARES, PO Box 68, 1970 AB IJmuiden (Netherlands)

    2011-07-15

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  8. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone; a compilation

    Energy Technology Data Exchange (ETDEWEB)

    Lindeboom, H J; Brasseur, S; Leopold, M; Scheidat, M [IMARES, PO Box 167, 1790 AD Den Burg (Netherlands); Kouwenhoven, H J [NoordzeeWind, 2e Havenstraat 5b, 1976 CE IJmuiden (Netherlands); Bergman, M J N; Daan, R [Royal NIOZ, PO Box 59, 1790 AB Den Burg (Netherlands); Bouma, S; Fijn, R C; Dirksen, S; Krijgsveld, K L [Bureau Waardenburg, PO Box 365, 4100 AJ Culemborg (Netherlands); De Haan, D; Van Hal, R; Hille Ris Lambers, R; Ter Hofstede, R, E-mail: han.lindeboom@wur.nl [IMARES, PO Box 68, 1970 AB IJmuiden (Netherlands)

    2011-07-15

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  9. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone. A compilation

    International Nuclear Information System (INIS)

    Lindeboom, H.J.; Brasseur, S.; Leopold, M.; Scheidat, M.; Kouwenhoven, H.J.; Bergman, M.J.N.; Daan, R.; Bouma, S.; Fijn, R.C.; Dirksen, S.; Krijgsveld, K.L.; De Haan, D.; Van Hal, R.; Hille Ris Lambers, R.; Ter Hofstede, R.

    2011-01-01

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  10. Fish farmers' perceptions of constraints affecting aquaculture ...

    African Journals Online (AJOL)

    The study focused on fish farmers' perceptions of constraints affecting aquaculture development in Akwa-Ibom State of Nigeria. Random sampling procedure was used to select 120 respondents from whom primary data was collected. Data analysis was with the aid of descriptive statistics. Results show that fish farming ...

  11. A standard deviation selection in evolutionary algorithm for grouper fish feed formulation

    Science.gov (United States)

    Cai-Juan, Soong; Ramli, Razamin; Rahman, Rosshairy Abdul

    2016-10-01

    Malaysia is one of the major producer countries for fishery production due to its location in the equatorial environment. Grouper fish is one of the potential markets in contributing to the income of the country due to its desirable taste, high demand and high price. However, the demand of grouper fish is still insufficient from the wild catch. Therefore, there is a need to farm grouper fish to cater to the market demand. In order to farm grouper fish, there is a need to have prior knowledge of the proper nutrients needed because there is no exact data available. Therefore, in this study, primary data and secondary data are collected even though there is a limitation of related papers and 30 samples are investigated by using standard deviation selection in Evolutionary algorithm. Thus, this study would unlock frontiers for an extensive research in respect of grouper fish feed formulation. Results shown that the fitness of standard deviation selection in evolutionary algorithm is applicable. The feasible and low fitness, quick solution can be obtained. These fitness can be further predicted to minimize cost in farming grouper fish.

  12. A NEW MODULA TYPO-DIMENSIONAL, CONSTRUCTIVE AND FUNCTIONAL CONCEPT OF VIVA DON EXPERT® FLOATABLE FISH CAGES FOR INTENSIVE AQUACULTURE IN INLAND WATERS

    Directory of Open Access Journals (Sweden)

    D. ONEA

    2009-10-01

    Full Text Available This scientific work presents succinct information about the trials which takes place between 2005-2009 in Constanta (fish farm Canalul Rompetrol. This trials includes the fish farming in cages and leads to finishing off and elaboration of a new modular typo-dimensional, constructive and functional concept of viva don Expert® floatable fish cages for intensive aquaculture in inland waters from Romania like an efficient solution for the qualitative and quantitative increase of local fish production’s (by water volume optimizations, plants, fish farms and technologies optimizations.

  13. Welfare of farmed fish - nutrition, breeding and diseases

    DEFF Research Database (Denmark)

    Buchmann, Kurt

    Proceeding on the workshop on Welfare of fish which was organised by the research school SCOFDA at KU-LIFE on April 11 and 12, 2007. Prooceedings comprise a total of 18 abstracts which were edited by Kurt Buchmann.......Proceeding on the workshop on Welfare of fish which was organised by the research school SCOFDA at KU-LIFE on April 11 and 12, 2007. Prooceedings comprise a total of 18 abstracts which were edited by Kurt Buchmann....

  14. Fish Kill in the Philippines—Déjà Vu

    Directory of Open Access Journals (Sweden)

    Gil Jacinto

    2011-12-01

    Full Text Available Almost ten years ago today, the country woke up toscreaming headlines— “Massive Fish Kill inPangasinan” or something akin to that. The fish killphenomenon, familiar to fishers in freshwater andcoastal bodies of water where fish farming was beingpursued, was suddenly manifested at a scale that hadheretofore not been experienced.

  15. The Adipose Tissue in Farm Animals

    DEFF Research Database (Denmark)

    Sauerwein, Helga; Bendixen, Emoke; Restelli, Laura

    2014-01-01

    and immune cells. The scientific interest in adipose tissue is largely based on the worldwide increasing prevalence of obesity in humans; in contrast, obesity is hardly an issue for farmed animals that are fed according to their well-defined needs. Adipose tissue is nevertheless of major importance...... in these animals, as the adipose percentage of the bodyweight is a major determinant for the efficiency of transferring nutrients from feed into food products and thus for the economic value from meat producing animals. In dairy animals, the importance of adipose tissue is based on its function as stromal...... and metabolic disorders. We herein provide a general overview of adipose tissue functions and its importance in farm animals. This review will summarize recent achievements in farm animal adipose tissue proteomics, mainly in cattle and pigs, but also in poultry, i.e. chicken and in farmed fish. Proteomics...

  16. “AquaTrace” The development of tools for tracing and evaluating the genetic impact of fish from aquaculture

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Bekkevold, Dorte; Svåsand, Terje

    2012-01-01

    Aquaculture represents a key solution to meet the escalating demand for fish. Accordingly, development of appropriate legislation within the European Union aquaculture sector underpinned by cutting‐edge research and technology is required. This necessitates implementation of breeding programmes...... to identify of the genetic origin of both wild and farmed fish (assignment and genetic traceability), as well as for the detection of interbreeding genetic introgression between farmed and wild stocks. This work will be carried out on three marine fish of economic significance: the European sea bass...... (Dicentrarchus labrax), gilthead sea bream (Sparus aurata), and turbot (Scophthalmus maximus). To address quantitative effects of farm introgression, the rationale is to examine links between key fitness and life‐history traits and specific functional genetic variation between wild and farmed fish, using...

  17. Review of mitigation methods for fish passage, instream flows, and water quality

    International Nuclear Information System (INIS)

    Railsback, S.F.

    1991-01-01

    This paper reports on current environmental mitigation practices at nonfederal hydropower projects. Information was obtained from project operators on dissolved oxygen (DO) mitigation, instream flows, upstream fish passage facilities, and downstream fish passage facilities. The most common method for DO mitigation is the use of spill flows, which are costly because of lost power generation. DO concentrations are commonly monitored, but biological effects of DO mitigation are not. At many projects, instream flow requirements have been set without reference to formalized methods. About half of the projects with instream flow requirements monitor flow rates, but few monitor fish populations to verify that instream flows are effective. Angled bar racks are the most commonly used downstream fish passage devices and fish ladders are the most commonly used upstream fish passage devices. Fish passage rates or populations have been monitored to verify the effectiveness of passage mitigation at few projects. This analysis is the first phase of an evaluation of the costs, benefits, and effectiveness of mitigation measures

  18. Velocity field in the wake of a hydropower farm equipped with Achard turbines

    International Nuclear Information System (INIS)

    Georgescu, A-M; Cosoiu, C I; Alboiu, N; Hamzu, Al; Georgescu, S C

    2010-01-01

    The study consists of experimental and numerical investigations related to the water flow in the wake of a hydropower farm, equipped with three Achard turbines. The Achard turbine is a French concept of vertical axis cross-flow marine current turbine, with three vertical delta-blades, which operates irrespective of the water flow direction. A farm model built at 1:5 scale has been tested in a water channel. The Achard turbines run in stabilized current, so the flow can be assumed to be almost unchanged in horizontal planes along the vertical z-axis, thus allowing 2D numerical modelling, for different farm configurations: the computational domain is a cross-section of all turbines at a certain z-level. The two-dimensional numerical model of that farm has been used to depict the velocity field in the wake of the farm, with COMSOL Multiphysics and FLUENT software, to compute numerically the overall farm efficiency. The validation of the numerical models with experimental results is performed via the measurement of velocity distribution, by Acoustic Doppler Velocimetry, in the wake of the middle turbine within the farm. Three basic configurations were studied experimentally and numerically, namely: with all turbines aligned on a row across the upstream flow direction; with turbines in an isosceles triangular arrangement pointing downstream; with turbines in an isosceles triangular arrangement pointing upstream. As long as the numerical flow in the wake fits the experiments, the numerical results for the power coefficient (turbine efficiency) are trustworthy. The farm configuration with all turbines aligned on a same row leads to lower values of the experimental velocities than the numerical ones, while the farm configurations where the turbines are in isosceles triangular arrangement, pointing downstream or upstream, present a better match between numerical and experimental data.

  19. 7 CFR 760.204 - Eligible livestock, honeybees, and farm-raised fish.

    Science.gov (United States)

    2010-01-01

    ..., goats, llamas, poultry, reindeer, sheep, or swine; (2) Be livestock that would normally have been... livestock that has been maintained for commercial use as part of the producer's farming operation on the... been produced and maintained for reasons other than commercial use as part of a farming operation; and...

  20. Fish passage mitigation of impacts from hydroelectric power projects in the United States

    International Nuclear Information System (INIS)

    Cada, G.F.

    1996-01-01

    Obstruction of fish movements by dams continues to be the major environmental issue facing the hydropower industry in the US. Dams block upstream migrations, which can cut off adult fish form their historical spawning grounds and severely curtail reproduction. Conversely, downstream-migrating fish may be entrained into the turbine intake flow and suffer turbine-passage injury or mortality. Hydroelectric projects can interfere with the migrations of a wide variety of fish. Maintenance, restoration or enhancement of populations of these species may require the construction of facilities to allow for upstream and downstream fish passage. The Federal Energy Regulatory Commission (FERC), by law, must give fish and wildlife resources equal consideration with power production in its licensing decisions, must be satisfied that a project is consistent with comprehensive plans for a waterway (including fisheries management plans), and must consider all federal and state resource agency terms and conditions for the protection of fish and wildlife. As a consequence, FERC often requires fish passage mitigation measures as a condition of the hydropower license when such measures are deemed necessary for the protection of fish. Much of the recent research and development efforts of the US Department of Energy's Hydropower Program have focused on the mitigation of impacts to upstream and downstream fish passage. This paper descries three components of that effort: (1) a survey of environmental mitigation measures at hydropower sites across the country; (2) a critical review of the effectiveness of fish passage mitigation measures at 16 case study sites; and (3) ongoing efforts to develop new turbine designs that minimize turbine-passage mortality

  1. Analysis of potential risks from the bacterial communities associated with air-contact surfaces from tilapia (Oreochromis niloticus) fish farming.

    Science.gov (United States)

    Grande Burgos, Maria Jose; Romero, Jose Luis; Pérez Pulido, Rubén; Cobo Molinos, Antonio; Gálvez, Antonio; Lucas, Rosario

    2018-01-01

    Tilapia farming is a promising growing sector in aquaculture. Yet, there are limited studies on microbiological risks associated to tilapia farms. The aim of the present study was to analyse the bacterial communities from solid surfaces in contact with air in a tilapia farm in order to evaluate the presence of bacteria potentially toxinogenic or pathogenic to humans or animals. Samples from a local tilapia farm (tank wall, aerator, water outlets, sink and floor) were analyzed by high throughput sequencing technology. Sequences were assigned to operational taxonomic units (OTUs). Proteobacteria was the main phylum represented in most samples (except for one). Cyanobacteria were a relevant phylum in the inner wall from the fattening tank and the wet floor by the pre-fattening tank. Bacteroidetes were the second phylum in relative abundance for samples from the larval rearing tank and the pre-fattening tank and one sample from the fattening tank. Fusobacteria showed highest relative abundances in samples from the larval rearing tank and pre-fattening tank. Other phyla (Verrucomicrobia, Actinobacteria, Firmicutes, Planktomycetes, Acidobacteria, Chloroflexi, Chlorobi, Gemmatiomonadetes or Fibrobacters) had lower relative abundances. A large fraction of the reads (ranging from 43.67% to 72.25%) were assigned to uncultured bacteria. Genus Acinetobacter (mainly A. calcoaceticus/baumanni) was the predominant OTU in the aerator of the fattening tank and also in the nearby sink on the floor. The genera Cetobacterium and Bacteroides showed highest relative abundances in the samples from the larval rearing tank and the pre-fattening tank. Genera including fish pathogens (Fusobacterium, Aeromonas) were only detected at low relative abundances. Potential human pathogens other than Acinetobacter were either not detected or had very low relative abundances (Acinetobacter and potential cyanotoxin-producing cyanobacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Relação parasito-hospedeiro em peixes de pisciculturas da região de Assis, Estado de São Paulo, Brasil. 1. Oreochromis niloticus (Linnaeus, 1757 - DOI: 10.4025/actascibiolsci.v29i2.594 Host-parasite relationship in fish from fish farms in the Assis region, São Paulo State, Brazil. 1. Oreochromis niloticus (Linnaeus, 1757

    Directory of Open Access Journals (Sweden)

    Maria José Tavares Ranzani-Paiva

    2007-12-01

    Full Text Available Um total de 90 espécimes de Oreochromis niloticus foi coletado bimestralmente entre os meses de fevereiro a dezembro de 2004, em três pisciculturas do Estado de São Paulo. Do total, 82,2% estavam parasitados por pelo menos uma espécie de parasito. Os parâmetros físicos e químicos da água foram utilizados para caracterizar a qualidade da água em cada propriedade. Sete espécies de ectoparasitos foram registradas. Foi possível observar que as pisciculturas apresentam a mesma parasitofauna, porém cada propriedade apresenta uma estrutura da comunidade peculiar. Cichlidogyrus sclerosus e Cichlidogyrus sp. 1 apresentaram correlação negativa significativa da abundância com o comprimento padrão do hospedeiro somente em Palmital. A espécie Cichlidogyrus sp. 2 e o copépode Lamproglena sp. apresentaram correlação positiva significativa da abundância com o comprimento padrão nas pisciculturas de Tarumã e Cândido Mota, respectivamente. Em relação ao fator de condição relativo, somente a espécie Cichlidogyrus sp. 1 apresentou correlação significativa negativa com a abundância de parasitismo. Lamproglena sp. apresentou correlação positiva significativa com a relação hepatossomática (RHS das tilápias em Palmital, e o ergasilídeo apresentou correlação significativa negativa da abundância de parasitismo e a relação esplenossomática (RES dos hospedeiros em Cândido Mota.A total of ninety specimens of Oreochromis niloticus were collected every other month between February and December of 2004 at three fish farms in São Paulo State. 82.2% were parasitized by at least one species of parasite. Physical and chemical water parameters were used to characterize water quality in each fish farm. Seven species of ectoparasites were registered. It was possible to observe that all fish farms presented the same parasite fauna; however, each farm featured its own peculiar community structure. Cichlidogyrus sclerosus and Cichlidogyrus

  3. Can Integrated Livestock-Fish Culture be a Solution to East Afircan's ...

    African Journals Online (AJOL)

    With the present high cost of pelleted fish feeds, integrated fish farming stands to reduce the cost of feeding fish while simultaneously increasing the yield, leading to high economic returns. This paper concludes that livestock-fish integration is one of the most practicable solutions to food insecurity and malnutrition in the East ...

  4. Influence of Moraxella sp. colonization on the kidney proteome of farmed gilthead sea breams (Sparus aurata, L.

    Directory of Open Access Journals (Sweden)

    Viale Iolanda

    2010-10-01

    Full Text Available Abstract Background Currently, presence of Moraxella sp. in internal organs of fish is not considered detrimental for fish farming. However, bacterial colonization of internal organs can affect fish wellness and decrease growth rate, stress resistance, and immune response. Recently, there have been reports by farmers concerning slow growth, poor feed conversion, and low average weight increase of fish farmed in offshore floating sea cages, often associated with internal organ colonization by Moraxella sp. Therefore, presence of these opportunistic bacteria deserves further investigations for elucidating incidence and impact on fish metabolism. Results A total of 960 gilthead sea breams (Sparus aurata, L., collected along 17 months from four offshore sea cage plants and two natural lagoons in Sardinia, were subjected to routine microbiological examination of internal organs throughout the production cycle. Thirteen subjects (1.35% were found positive for Moraxella sp. in the kidney (7, brain (3, eye (1, spleen (1, and perivisceral fat (1. In order to investigate the influence of Moraxella sp. colonization, positive and negative kidney samples were subjected to a differential proteomics study by means of 2-D PAGE and mass spectrometry. Interestingly, Moraxella sp. infected kidneys displayed a concerted upregulation of several mitochondrial enzymes compared to negative tissues, reinforcing previous observations following lipopolysaccharide (LPS challenge in fish. Conclusions Presence of Moraxella sp. in farmed sea bream kidney is able to induce proteome alterations similar to those described following LPS challenge in other fish species. This study revealed that Moraxella sp. might be causing metabolic alterations in fish, and provided indications on proteins that could be investigated as markers of infection by Gram-negative bacteria within farming plants.

  5. Fish assemblages in the Upper Esopus Creek, NY: Current status, variability, and controlling factors

    Science.gov (United States)

    Baldigo, Barry P.; George, Scott D.; Keller, Walter T

    2015-01-01

    The Upper Esopus Creek receives water diversions from a neighboring basin through the Shandaken Tunnel (the portal) from the Schoharie Reservoir. Although the portal is closed during floods, mean flows and turbidity of portal waters are generally greater than in Esopus Creek above their confluence. These conditions could potentially affect local fish assemblages, yet such effects have not been assessed in this highly regulated stream. We studied water quality, hydrology, temperature, and fish assemblages at 18 sites in the Upper Esopus Creek during 2009–2011 to characterize the effects of the portal input on resident-fish assemblages and to document the status of the fishery resource. In general, fish-community richness increased by 2–3 species at mainstem sites near the portal, and median density and biomass of fish communities at sites downstream of the portal were significantly lower than they were at sites upstream of the portal. Median densities of Salmo trutta (Brown Trout) and all trout species were significantly lower than at mainstem sites downstream from the portal—25.1 fish/0.1 ha and 148.9 fish/0.1 ha, respectively—than at mainstem sites upstream from the portal—68.8 fish/0.1 ha and 357.7 fish/0.1 ha, respectively—yet median biomass for Brown Trout and all trout did not differ between sites from both reaches. The median density of young-of-year Brown Trout at downstream sites (9.3 fish/0.1 ha) was significantly lower than at upstream sites (33.9 fish/0.1 ha). Waters from the portal appeared to adversely affect the density and biomass of young-of-year Brown Trout, but lower temperatures and increased flows also improved habitat quality for mature trout at downstream sites during summer. These findings, and those from companion studies, indicate that moderately turbid waters from the portal had few if any adverse impacts on trout populations and overall fish communities in the Upper Esopus Creek during this study.

  6. Fish schooling as a basis for vertical axis wind turbine farm design.

    Science.gov (United States)

    Whittlesey, Robert W; Liska, Sebastian; Dabiri, John O

    2010-09-01

    Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16 x 16 wind turbines. The results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

  7. Fish schooling as a basis for vertical axis wind turbine farm design

    International Nuclear Information System (INIS)

    Whittlesey, Robert W; Liska, Sebastian; Dabiri, John O

    2010-01-01

    Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16 x 16 wind turbines. The results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

  8. Wake interaction and power production of variable height model wind farms

    International Nuclear Information System (INIS)

    Vested, M H; Sørensen, J N; Hamilton, N; Cal, R B

    2014-01-01

    Understanding wake dynamics is an ongoing research topic in wind energy, since wakes have considerable effects on the power production when wind turbines are placed in a wind farm. Wind tunnel experiments have been conducted to study the wake to wake interaction in a model wind farm in tandem with measurements of the extracted power. The aim is to investigate how alternating mast height influences the interaction of the wakes and the power production. Via the use of stereo-particle image velocimetry, the flow field was obtained in the first and last rows of the wind turbine array as a basis of comparison. It was found that downstream of the exit row wind turbine, the power was increased by 25% in the case of a staggered height configuration. This is partly due to the fact that the taller turbines reach into a flow area with a softened velocity gradient. Another aspect is that the wake downstream of a tall wind turbine to some extent passes above the standard height wind turbine. Overall the experiments show that the velocity field downstream of the exit row changes considerably when the mast height is alternating

  9. Waste management of shrimp farms as starting point to develop integrated farming systems (case study: Kuwaru Coast, Bantul, Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    H.G. Saiya

    2015-10-01

    Full Text Available Intensive waste management is a solution to maintain an area of ecological harmony but still can produce economic benefits that are beneficial to social welfare. So in this research, waste of shrimp farms which was just processed by using zeolite, was treated again with a few treatments, i.e. simple filters, constructed wetlands, shell, fish and composting. Simple filters were composed of stone, gravel, coral, charcoal, sand and coconut fibers. Constructed wetland system used was hybrid type which combines type of horizontal flow and type of vertical flow. The shell used was Polymesoda erosa. The fish used was Tilapia. In the composting sediment activator, biang kompos was used with the composting time of one month. The results indicated that the system of simple filters, constructed wetlands, shells and fish proved to be quite effective to reduce levels of pollutants in wastewater and will be more effective if treatment was accompanied with a proper aeration. While, the sediment composted into fertilizer needed to be composted with a longer time than normal composting time. This was because the composted materials were derived from waste having a very low nutrient, so it took longer to restore nutrients. The results also indicated the potential of shrimp farm waste of PT. IBD to be processed into clean water and fertilizer. With the appropriate policies and strategies, this can lead to the development of an integrated farming system to support sustainable coastal ecologically, economically and socially.

  10. Effects of changes in food supply at the time of sex differentiation on the gonadal transcriptome of juvenile fish. Implications for natural and farmed populations.

    Science.gov (United States)

    Díaz, Noelia; Ribas, Laia; Piferrer, Francesc

    2014-01-01

    Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish. This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1) 4-month-old sexually undifferentiated fish, comparing the gonads of fish with the highest vs. the lowest growth, to explore a possible link between transcriptome and future sex, and 2) testis from 11-month-old juveniles where growth had been manipulated through changes in food supply. The four groups used were: i) sustained fast growth, ii) sustained slow growth, iii) accelerated growth, iv) decelerated growth. The transcriptome of undifferentiated gonads was not drastically affected by initial natural differences in growth. Further, changes in the expression of genes associated with protein turnover were seen, favoring catabolism in slow-growing fish and anabolism in fast-growing fish. Moreover, while fast-growing fish took energy from glucose, as deduced from the pathways affected and the analysis of protein-protein interactions examined, in slow-growing fish lipid metabolism and gluconeogenesis was favored. Interestingly, the highest transcriptomic differences were found when forcing initially fast-growing fish to decelerate their growth, while accelerating growth of initially slow-growing fish resulted in full transcriptomic convergence with sustained fast-growing fish. Food availability during sex differentiation shapes the juvenile testis transcriptome, as evidenced by adaptations to different energy balances. Remarkably, this occurs in absence of major histological changes in the testis. Thus, fish are able to recover transcriptionally their testes if they are provided with enough food supply during sex differentiation; however

  11. Summer yield of fish in polyculture in Transkei, South Africa, using ...

    African Journals Online (AJOL)

    Keywords Aquaculture, fish prOduction, polyculture, integrated farming ... *To whom all correspondence should be addressed. Introduction. The use of animal wastes in fish production systems, has been widely practised for centuries in the Far Eastern countries ..... water without problems in fish-pond management. Hybrids.

  12. DNA vaccines for aquacultured fish

    DEFF Research Database (Denmark)

    Lorenzen, Niels; LaPatra, S.E.

    2005-01-01

    of licensing and public acceptance of the technology. The potential benefits of DNA vaccines for farmed fish include improved animal welfare, reduced environmental impacts of aquaculture activities, increased food quality and quantity, and more sustainable production. Testing under commercial production......Deoxyribonucleic acid (DNA) vaccination is based on the administration of the gene encoding the vaccine antigen, rather than the antigen itself. Subsequent expression of the antigen by cells in the vaccinated hosts triggers the host immune system. Among the many experimental DNA vaccines tested...... in various animal species as well as in humans, the vaccines against rhabdovirus diseases in fish have given some of the most promising results. A single intramuscular (IM) injection of microgram amounts of DNA induces rapid and long-lasting protection in farmed salmonids against economically important...

  13. Helminthes and protozoan of farmed pirarucu (Arapaima gigas in eastern Amazon and host-parasite relationship

    Directory of Open Access Journals (Sweden)

    R.G.B. Marinho

    2013-08-01

    Full Text Available The parasitofauna in the giant Amazon basin, pirarucu (Arapaima gigas Schinz, 1822 cultured in fish farms from the state of Amapá, in eastern Amazonia (Brazil was investigated. Of the 100 examined fish, 90.0% were parasitized by Ichthyophthirius multifiliis (Ciliophora, Dawestrema cycloancistrium, Dawestrema cycloancistrioides (Monogenoidea and Polyacanthorhynchus macrorhynchus (Acanthocephala, which had an aggregated distribution pattern. The highest infection rates were caused by I. multifiliis and the lowest by P. macrorhynchus. Infection rates were different for each fish farm, due to different water quality and management characteristics. A negative correlation was found between the intensity of monogenoideans D. cycloancistrium and D. cycloancistrioides and the relative condition factor (Kn, but the welfare of fish was not affected by parasitism. The number of I. multifiliis was positively correlated with the weight and total length of hosts, while the intensity of monogenoideans was negatively correlated with body weight and total length. This study is the first to record the occurrence of P. macrorhynchus in A. gigas farmed in Amazon.

  14. Status and habitat requirements of the white sturgeon populations in the Columbia River downstream from McNary Dam

    International Nuclear Information System (INIS)

    Nigro, A.A.

    1991-09-01

    We report on our progress from April 1990 through March 1991 on determining the status and habitat requirements of white sturgeon populations in the Columbia River downstream from McNary Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW), Washington Department of Fisheries (WDF), US Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS). Study objectives addressed by each agency are to describe the life history and population dynamics of subadults and adults between Bonneville and McNary dams and evaluate the need and identify potential methods for protecting, mitigating and enhancing populations downstream from NcNary Dam; to describe the white sturgeon recreational fishery between Bonneville and McNary dams, describe reproductive and early life history characteristics downstream from Bonneville Dam and describe life history and population dynamics of subadults and adults downstream from Bonneville Dam; to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available between Bonneville and McNary dams; and to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available downstream from Bonneville Dam. Our approach is to work concurrently downstream and upstream from Bonneville Dam. Upstream from Bonneville Dam we began work in the Dalles Reservoir in 1987 and expanded efforts to Bonneville Reservoir in 1988 and John Day Reservoir in 1989. Highlights of results of this work in the Dalles, Bonneville and John Day reservoirs are included in the four pages included in this report

  15. Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Data report 2001

    International Nuclear Information System (INIS)

    Leonhard, S.B.; Pedersen, John

    2002-08-01

    The Ministry of Environment and Energy requested ELSAM and ELTRA to establish an offshore wind farm with an output of 150 MW in the waters of Horns Rev, approximately 15 km off Blaevandshuk, which is the most westerly point of Denmark. The first phase of construction of the wind farm have started in spring 2002. Before the construction activities take place, a baseline description of the benthos has been conducted as a part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines for offshore wind farms prepared by the Danish Energy Agency. The monitoring programme established for the benthic infauna was performed in spring 2001. In addition to a proposed fish investigation programme concerning the stomach contents of fish a comparative programme on benthos was established as part of the monitoring programme. The benthos sampling in connection with the fish programme was conducted in autumn 2001. This benthic survey includes sampling in a proposed reference area for the fish surveys north east of the wind farm. This report presents the data of the baseline environmental survey of the seabed in the wind farm site and in the proposed reference site and a brief description of the weather conditions at the time of sampling. (au)

  16. The effects of tertiary treated municipal wastewater on fish communities of a small river tributary in Southern Ontario, Canada

    International Nuclear Information System (INIS)

    Brown, Carolyn J.M.; Knight, Brendan W.; McMaster, Mark E.; Munkittrick, Kelly R.; Oakes, Ken D.; Tetreault, Grald R.; Servos, Mark R.

    2011-01-01

    Fish community changes associated with a tertiary treated municipal wastewater effluent outfall in the Speed River, Ontario, Canada, were evaluated at nine sites over two seasons (2008) using standardized electrofishing. Habitat evaluations were conducted to ensure that the riffle sites selected were physically similar. The fish community was dominated by several species of darters that differed in their response to the effluent outfall. There was a significant decrease in Greenside Darter (Etheostoma blennioides) but an increase in Rainbow Darter (E. caeruleum) abundance directly downstream of the outfall. Stable isotope signatures (δ 13 C and δ 15 N), which indicate shifts in energy utilization and flow, increased in Rainbow Darter downstream, but showed no change in Greenside Darter. Rainbow Darter may be exploiting a food source that is not as available at upstream sites giving them a competitive advantage over the Greenside Darter immediately downstream of the outfall. - Highlights: → Fish communities are altered by tertiary treated municipal wastewater exposure. → Relative abundance of the two dominant fish (darter) species changed downstream. → Differing stable isotope signatures in fish suggests shifting energy flow and diet. → The altered environment may allow resilient species a competitive advantage. → The system recovers quickly downstream. - Tertiary treated effluent altered fish community composition in a small receiving stream possibly as a result of altered availability of resources (diet) as indicated by stable isotopes.

  17. A stochastic frontier analysis of technical efficiency of fish cage culture in Peninsular Malaysia.

    Science.gov (United States)

    Islam, Gazi Md Nurul; Tai, Shzee Yew; Kusairi, Mohd Noh

    2016-01-01

    Cage culture plays an important role in achieving higher output and generating more export earnings in Malaysia. However, the cost of fingerlings, feed and labour have increased substantially for cage culture in the coastal areas in Peninsular Malaysia. This paper uses farm level data gathered from Manjung, Perak and Kota Tinggi, Johor to investigate the technical efficiency of brackish water fish cage culture using the stochastic frontier approach. The technical efficiency was estimated and specifically the factors affecting technical inefficiencies of fish cage culture system in Malaysia was investigated. On average, 37 percent of the sampled fish cage farms are technically efficient. The results suggest very high degrees of technical inefficiency exist among the cage culturists. This implies that great potential exists to increase fish production through improved efficiency in cage culture management in Peninsular Malaysia. The results indicate that farmers obtained grouper fingerlings from other neighboring countries due to scarcity of fingerlings from wild sources. The cost of feeding for grouper (Epinephelus fuscoguttatus) requires relatively higher costs compared to seabass (Lates calcarifer) production in cage farms in the study areas. Initiatives to undertake extension programmes at the farm level are needed to help cage culturists in utilizing their resources more efficiently in order to substantially enhance their fish production.

  18. Current situation of fish farming in Togo

    African Journals Online (AJOL)

    practiced in ponds and water reservoirs and the semi intensive system (12.09%) implemented in tanks and ponds .... primarily intended to be a source of drinking water ... big fish at regular intervals. .... has the advantage of requiring little space.

  19. The analysis of physicochemical characteristics of pig farm seepage ...

    African Journals Online (AJOL)

    Dikonketso Matjuda

    -bodies, promoting ... that the seepage from pig farm degraded the natural environment by causing eutrophication, promote ... mainly livestock droppings, heavy metals, fertilizers and ... from microorganisms to insects, birds, fish, and at the.

  20. MORTALITY OF YOUTH Arapaima gigas (PISCES: ARAPAIMIDAE FROM A FISH FARMING IN THE NORTH OF BRAZIL, CAUSED BY Hysterothylacium sp. AND Goezia spinulosa (NEMATODA: ANISAKIDAE

    Directory of Open Access Journals (Sweden)

    Patrizia Batista de Azevedo

    2017-03-01

    Full Text Available In youth A. gigas the risk of parasitic infections is very high, due to their feeding habit to prey on small invertebrates, which act as intermediate hosts of different endoparasite species, which can cause serious problems and high mortalities in fish farms. Thus, the aim of the present study was to identify the species that parasitize youth A. gigas raised in captivity in the Manacapuru municipality, Amazonas State and to evaluate their influence on the mortality of these fish. There were examined 66 youth A. gigas and non-parasite was recorded in the host gills. The intestine and stomach of the fish were parasitized by Hysterothylacium sp. larvae (L3 and Goezia spinulosa larvae (L4. The parasitic indexes were high for the two species, being recorded the highest rates of infection by Hysterothylacium sp. There was observed a weak positive correlation between the host standard length and the abundance of Hysterothylacium sp. The lesions observed in the stomach and intestine of the fish, together with the high parasite index values recorded for Hysterothylacium sp. and Goezia spinulosa, leads to the suspicion that the death of the fish was due to complications and damages caused by the presence of these parasites. Keywords: Amazonia; arapaima; death; nematodes.

  1. Fish assemblage structure and habitat associations in a large western river system

    Science.gov (United States)

    Smith, C.D.; Quist, Michael C.; Hardy, R. S.

    2016-01-01

    Longitudinal gradients of fish assemblage and habitat structure were investigated in the Kootenai River of northern Idaho. A total of 43 500-m river reaches was sampled repeatedly with several techniques (boat-mounted electrofishing, hoop nets and benthic trawls) in the summers of 2012 and 2013. Differences in habitat and fish assemblage structure were apparent along the longitudinal gradient of the Kootenai River. Habitat characteristics (e.g. depth, substrate composition and water velocity) were related to fish assemblage structure in three different geomorphic river sections. Upper river sections were characterized by native salmonids (e.g. mountain whitefish Prosopium williamsoni), whereas native cyprinids (peamouth Mylocheilus caurinus, northern pikeminnow Ptychocheilus oregonensis) and non-native fishes (pumpkinseed Lepomis gibbosus, yellow perch Perca flavescens) were common in the downstream section. Overall, a general pattern of species addition from upstream to downstream sections was discovered and is likely related to increased habitat complexity and additions of non-native species in downstream sections. Assemblage structure of the upper sections were similar, but were both dissimilar to the lower section of the Kootenai River. Species-specific hurdle regressions indicated the relationships among habitat characteristics and the predicted probability of occurrence and relative abundance varied by species. Understanding fish assemblage structure in relation to habitat could improve conservation efforts of rare fishes and improve management of coldwater river systems.

  2. Fish and aquatic organisms [Chapter 9

    Science.gov (United States)

    John N. Rinne

    2012-01-01

    The UVR of central Arizona, from its source at Sullivan Lake to the mouth of Sycamore Creek, 60 km (38 mi) downstream, is rare among the State’s rivers because it still retains some of its native fish fauna. In 1994, six of the native fishes that were historically recorded in this reach of the Verde still occurred, along with at least seven nonnative species, and many...

  3. Fish Vaccine Development and Use to Prevent Streptococcal Diseases

    Science.gov (United States)

    An important pathogen of tilapia, hybrid striped bass and trout raised in intensive aquaculture is Streptococcus sp., a cause of severe economic losses in the fish farming industry. Infected fish experience severe to moderate mortality due to Streptococcus iniae and/or S. agalactiae. The diseased ...

  4. Influences of body size and environmental factors on autumn downstream migration of bull trout in the Boise River, Idaho

    Science.gov (United States)

    Monnot, L.; Dunham, J.B.; Hoem, T.; Koetsier, P.

    2008-01-01

    Many fishes migrate extensively through stream networks, yet patterns are commonly described only in terms of the origin and destination of migration (e.g., between natal and feeding habitats). To better understand patterns of migration in bull trout,Salvelinus confluentus we studied the influences of body size (total length [TL]) and environmental factors (stream temperature and discharge) on migrations in the Boise River basin, Idaho. During the autumns of 2001-2003, we tracked the downstream migrations of 174 radio-tagged bull trout ranging in size from 21 to 73 cm TL. The results indicated that large bull trout (>30 cm) were more likely than small fish to migrate rapidly downstream after spawning in headwater streams in early autumn. Large bull trout also had a higher probability of arriving at the current terminus of migration in the system, Arrowrock Reservoir. The rate of migration by small bull trout was more variable and individuals were less likely to move into Arrowrock Reservoir. The rate of downstream migration by all fish was slower when stream discharge was greater. Temperature was not associated with the rate of migration. These findings indicate that fish size and environmentally related changes in behavior have important influences on patterns of migration. In a broader context, these results and other recent work suggest, at least in some cases, that commonly used classifications of migratory behavior may not accurately reflect the full range of behaviors and variability among individuals (or life stages) and environmental conditions. ?? Copyright by the American Fisheries Society 2008.

  5. The importance of live-feed traps - farming marine fish species

    DEFF Research Database (Denmark)

    Nielsen, Rasmus; Nielsen, Max; Abate, Tenaw Gedefaw

    2017-01-01

    This article analyses the challenges of different live-feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live-feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine...... shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited...... wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live-feed resources and development of new sustainable alternatives, such as copepods. An array...

  6. Planning Guide for Fish Passage at Pittsburgh District Dams

    Science.gov (United States)

    2013-08-01

    attracted to a downstream flow at the entrance gate of the lift. 2) Immigrants pass around a moveable crowder that, when engaged, forces fish into the...might influence fish passage over a large number of sites. REFERENCES Bailey, M. M., J. J. Isely, and W. C. Bridges , Jr. 2004. Movement and

  7. Effects of historical lead–zinc mining on riffle-dwelling benthic fish and crayfish in the Big River of southeastern Missouri, USA

    Science.gov (United States)

    Allert, A.L.; DiStefano, R.J.; Fairchild, J.F.; Schmitt, C.J.; McKee, M.J.; Girondo, J.A.; Brumbaugh, W.G.; May, T.W.

    2013-01-01

    The Big River (BGR) drains much of the Old Lead Belt mining district (OLB) in southeastern Missouri, USA, which was historically among the largest producers of lead–zinc (Pb–Zn) ore in the world. We sampled benthic fish and crayfish in riffle habitats at eight sites in the BGR and conducted 56-day in situ exposures to the woodland crayfish (Orconectes hylas) and golden crayfish (Orconectes luteus) in cages at four sites affected to differing degrees by mining. Densities of fish and crayfish, physical habitat and water quality, and the survival and growth of caged crayfish were examined at sites with no known upstream mining activities (i.e., reference sites) and at sites downstream of mining areas (i.e., mining and downstream sites). Lead, zinc, and cadmium were analyzed in surface and pore water, sediment, detritus, fish, crayfish, and other benthic macro-invertebrates. Metals concentrations in all materials analyzed were greater at mining and downstream sites than at reference sites. Ten species of fish and four species of crayfish were collected. Fish and crayfish densities were significantly greater at reference than mining or downstream sites, and densities were greater at downstream than mining sites. Survival of caged crayfish was significantly lower at mining sites than reference sites; downstream sites were not tested. Chronic toxic-unit scores and sediment probable effects quotients indicated significant risk of toxicity to fish and crayfish, and metals concentrations in crayfish were sufficiently high to represent a risk to wildlife at mining and downstream sites. Collectively, the results provided direct evidence that metals associated with historical mining activities in the OLB continue to affect aquatic life in the BGR.

  8. Management of groundwater in farmed pond area using risk-based regulation.

    Science.gov (United States)

    Huang, Jun-Ying; Liao, Chiao-Miao; Lin, Kao-Hung; Lee, Cheng-Haw

    2014-09-01

    Blackfoot disease (BFD) had occurred seriously in the Yichu, Hsuehchia, Putai, and Peimen townships of Chia-Nan District of Taiwan in the early days. These four townships are the districts of fishpond cultivation domestically in Taiwan. Groundwater becomes the main water supply because of short income in surface water. The problems of over pumping in groundwater may not only result in land subsidence and seawater intrusion but also be harmful to the health of human giving rise to the bioaccumulation via food chain in groundwater with arsenic (As). This research uses sequential indicator simulation (SIS) to characterize the spatial arsenic distribution in groundwater in the four townships. Risk assessment is applied to explore the dilution ratio (DR) of groundwater utilization, which is defined as the ratio showing the volume of groundwater utilization compared to pond water, for fish farming in the range of target cancer risk (TR) especially on the magnitude of 10(-4)~10(-6). Our study results reveal that the 50th percentile of groundwater DRs served as a regulation standard can be used to perform fish farm groundwater management for a TR of 10(-6). For a TR of 5 × 10(-6), we suggest using the 75th percentile of DR for groundwater management. For a TR of 10(-5), we suggest using the 95th percentile of the DR standard for performing groundwater management in fish farm areas. For the TR of exceeding 5 × 10(-5), we do not suggest establishing groundwater management standards under these risk standards. Based on the research results, we suggest that establishing a TR at 10(-5) and using the 95th percentile of DR are best for groundwater management in fish farm areas.

  9. The Skin-Mucus Microbial Community of Farmed Atlantic Salmon (Salmo salar)

    Science.gov (United States)

    Minniti, Giusi; Hagen, Live Heldal; Porcellato, Davide; Jørgensen, Sven Martin; Pope, Phillip B.; Vaaje-Kolstad, Gustav

    2017-01-01

    The skin of the teleost is a flexible and scaled structure that protects the fish toward the external environment. The outermost surface of the skin is coated with mucus, which is believed to be colonized by a diverse bacterial community (commensal and/or opportunistic). Little is known about such communities and their role in fish welfare. In aquaculture, fish seem to be more susceptible to pathogens compared to wild fish. Indeed common fish farming practices may play important roles in promoting their vulnerability, possibly by causing changes to their microbiomes. In the present study, 16S rRNA gene amplicon sequencing was employed to analyze the composition of the farmed Salmo salar skin-mucus microbiome before and after netting and transfer. The composition of the bacterial community present in the rearing water was also investigated in order to evaluate its correlation with the community present on the fish skin. Our results reveal variability of the skin-mucus microbiome among the biological replicates before fish handling. On the contrary, after fish handling, the skin-mucus community exhibited structural similarity among the biological replicates and significant changes were observed in the bacterial composition compared to the fish analyzed prior to netting and transfer. Limited correlation was revealed between the skin-mucus microbiome and the bacterial community present in the rearing water. Finally, analysis of skin-mucus bacterial biomasses indicated low abundance for some samples, highlighting the need of caution when interpreting community data due to the possible contamination of water-residing bacteria. PMID:29104567

  10. The Skin-Mucus Microbial Community of Farmed Atlantic Salmon (Salmo salar

    Directory of Open Access Journals (Sweden)

    Giusi Minniti

    2017-10-01

    Full Text Available The skin of the teleost is a flexible and scaled structure that protects the fish toward the external environment. The outermost surface of the skin is coated with mucus, which is believed to be colonized by a diverse bacterial community (commensal and/or opportunistic. Little is known about such communities and their role in fish welfare. In aquaculture, fish seem to be more susceptible to pathogens compared to wild fish. Indeed common fish farming practices may play important roles in promoting their vulnerability, possibly by causing changes to their microbiomes. In the present study, 16S rRNA gene amplicon sequencing was employed to analyze the composition of the farmed Salmo salar skin-mucus microbiome before and after netting and transfer. The composition of the bacterial community present in the rearing water was also investigated in order to evaluate its correlation with the community present on the fish skin. Our results reveal variability of the skin-mucus microbiome among the biological replicates before fish handling. On the contrary, after fish handling, the skin-mucus community exhibited structural similarity among the biological replicates and significant changes were observed in the bacterial composition compared to the fish analyzed prior to netting and transfer. Limited correlation was revealed between the skin-mucus microbiome and the bacterial community present in the rearing water. Finally, analysis of skin-mucus bacterial biomasses indicated low abundance for some samples, highlighting the need of caution when interpreting community data due to the possible contamination of water-residing bacteria.

  11. Longitudinal structure in temperate stream fish communities: evaluating conceptual models with temporal data

    Science.gov (United States)

    Roberts, James H.; Hitt, Nathaniel P.

    2010-01-01

    Five conceptual models of longitudinal fish community organization in streams were examined: (1) niche diversity model (NDM), (2) stream continuum model (SCM), (3) immigrant accessibility model (IAM), (4) environmental stability model (ESM), and (5) adventitious stream model (ASM). We used differences among models in their predictions about temporal species turnover, along with five spatiotemporal fish community data sets, to evaluate model applicability. Models were similar in predicting a positive species richness–stream size relationship and longitudinal species nestedness, but differed in predicting either similar temporal species turnover throughout the stream continuum (NDM, SCM), higher turnover upstream (IAM, ESM), or higher turnover downstream (ASM). We calculated measures of spatial and temporal variation from spatiotemporal fish data in five wadeable streams in central and eastern North America spanning 34–68 years (French Creek [New York], Piasa Creek [Illinois], Spruce Run [Virginia], Little Stony Creek [Virginia], and Sinking Creek [Virginia]). All streams exhibited substantial species turnover (i.e., at least 27% turnover in stream-scale species pools), in contrast to the predictions of the SCM. Furthermore, community change was greater in downstream than upstream reaches in four of five streams. This result is most consistent with the ASM and suggests that downstream communities are strongly influenced by migrants to and from species pools outside the focal stream. In Sinking Creek, which is isolated from external species pools, temporal species turnover (via increased richness) was higher upstream than downstream, which is a pattern most consistent with the IAM or ESM. These results corroborate the hypothesis that temperate stream habitats and fish communities are temporally dynamic and that fish migration and environmental disturbances play fundamental roles in stream fish community organization.

  12. Net ground speed of downstream migrating radio-tagged Atlantic salmon ( Salmo salar L.) and brown trout ( Salmo trutta L.) smolts in relation to environmental factors

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Nielsen, C.; Koed, Anders

    2002-01-01

    tagged and released in the Danish River Lilleaa. The downstream migration of the different groups of fish was monitored by manual tracking and by three automatic listening stations. The downstream migration of radio tagged smolts of both species occurred concurrently with their untagged counterparts....... The diel migration pattern of the radio tagged smolts was predominantly nocturnal in both species. Wild sea trout smolt migrated significantly faster than both the F1 trout and the introduced salmon. There was no correlation between net ground speed, gill Na+, K+-ATPase activity or fish length in any...

  13. Wind Turbine Power Curve Design for Optimal Power Generation in Wind Farms Considering Wake Effect

    Directory of Open Access Journals (Sweden)

    Jie Tian

    2017-03-01

    Full Text Available In modern wind farms, maximum power point tracking (MPPT is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its downstream wind turbines due to the wake effect. According to the wake model, downstream power loss is also determined by the pitch angle and tip speed ratio of the upstream wind turbine. By optimizing the pitch angle and tip speed ratio of each wind turbine, the total active power of the wind farm can be increased. In this paper, the optimal pitch angle and tip speed ratio are selected for each wind turbine by the exhausted search. Considering the estimation error of the wake model, a solution to implement the optimized pitch angle and tip speed ratio is proposed, which is to generate the optimal control curves for each individual wind turbine off-line. In typical wind farms with regular layout, based on the detailed analysis of the influence of pitch angle and tip speed ratio on the total active power of the wind farm by the exhausted search, the optimization is simplified with the reduced computation complexity. By using the optimized control curves, the annual energy production (AEP is increased by 1.03% compared to using the MPPT method in a case-study of a typical eighty-turbine wind farm.

  14. The Sole Question. Assessing the sustainability of fishing versus farming

    NARCIS (Netherlands)

    Broenland, Eefje

    2007-01-01

    Fish stocks in the world are declining, but the demand for fish products is increasing. Aquaculture practices are increasing because of this gap between supply and demand. Therefore it is important to determine which production system has the least enviro

  15. Haematological and histopathological analysis in South American fish Piaractus mesopotamicus parasitized by monogenean (Dactylogyridae

    Directory of Open Access Journals (Sweden)

    GT Jerônimo

    Full Text Available Monogeneans are the parasites mostly found on the body surface and gills of fish and can cause large losses in farmed fish. Some studies demonstrate elevated parasitic levels causing hematological alterations. But few of them relate the effects of parasitism on the hematology and histopathology of native freshwater farmed fish. This study evaluated the host-parasite relationship in pacu (Piaractus mesopotamicus parasitized by the monogenean Anacanthorus penilabiatus. Hematological and parasitological assessments were obtained in 60 fish captured in a fish farm located in Dourados, State of Mato Grosso do Sul, Central Brazil. Fish were analyzed in different categories of parasite number: class I (n=13; 0-200 parasites, class II (n=17; 201-1200 parasites; class III (n=7; 1201-2200 parasites; and class IV (n=23; more than 2200 parasites per host. The highest levels of parasitism caused significant decrease (p<0.05 in the hematocrit, red blood cells (RBC, mean hemoglobin concentration (MCHC and basophils number. Thrombocytes, mean corpuscular volume (MCV, mean corpuscular hemoglobin concentration (MCHC, monocytes, eosinophils, neutrophils and LG-PAS did not present significant difference among the parasitic levels. In contrast, increased number of total leukocytes and lymphocytes were found in highly-parasitized fish. A positive linear correlation (p<0.01 was found between the amount of parasites and fish weight. Histopathology revealed severe hyperplasia, sub-epithelial edema, fusion of the secondary lamellae, focal and multifocal necrosis in highly parasitized fish.

  16. Effects of changes in food supply at the time of sex differentiation on the gonadal transcriptome of juvenile fish. Implications for natural and farmed populations.

    Directory of Open Access Journals (Sweden)

    Noelia Díaz

    Full Text Available Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish.This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1 4-month-old sexually undifferentiated fish, comparing the gonads of fish with the highest vs. the lowest growth, to explore a possible link between transcriptome and future sex, and 2 testis from 11-month-old juveniles where growth had been manipulated through changes in food supply. The four groups used were: i sustained fast growth, ii sustained slow growth, iii accelerated growth, iv decelerated growth. The transcriptome of undifferentiated gonads was not drastically affected by initial natural differences in growth. Further, changes in the expression of genes associated with protein turnover were seen, favoring catabolism in slow-growing fish and anabolism in fast-growing fish. Moreover, while fast-growing fish took energy from glucose, as deduced from the pathways affected and the analysis of protein-protein interactions examined, in slow-growing fish lipid metabolism and gluconeogenesis was favored. Interestingly, the highest transcriptomic differences were found when forcing initially fast-growing fish to decelerate their growth, while accelerating growth of initially slow-growing fish resulted in full transcriptomic convergence with sustained fast-growing fish.Food availability during sex differentiation shapes the juvenile testis transcriptome, as evidenced by adaptations to different energy balances. Remarkably, this occurs in absence of major histological changes in the testis. Thus, fish are able to recover transcriptionally their testes if they are provided with enough food supply during sex

  17. Net cages in fish farming: a scientometric analysis Tanques rede em piscicultura: uma análise cienciométrica

    Directory of Open Access Journals (Sweden)

    Juliana Déo Dias

    2012-03-01

    Full Text Available AIM: This study presents a scientometric analysis of studies on net cages in order to determine whether these studies are considering environmental issues or only seeking an increase in food production; METHODS: The survey of articles was accomplished using the Thomson Reuters Database (ISI Web of Knowledge, with "cage culture" and "net cage" as keywords. We selected 238 articles that were published between 1990 and 2009; RESULTS: There was a temporal increase in the number of articles published. These articles focused mainly on fish production and environmental impacts; CONCLUSION: The studies of net cages in fish farming mainly investigated fish production, although environmental issues relating to this recent human activity were also important. Policy makers should consider both sides of the coin (i.e., both the benefits and environmental impacts of fish production in regulation of this activity.OBJETIVO: O presente estudo teve como objetivo apresentar uma análise cienciométrica sobre os estudos de tanques rede, a fim de responder se estes estudos estão considerando as questões ambientais ou, apenas, buscam um aumento na produção de alimentos; MÉTODOS: O levantamento dos artigos foi realizado na base Thomson Reuters (ISI Web of Knowledge, sendo utilizadas "cage culture" e "net cage" como palavras-chave. Foram selecionados 238 artigos durante o período de 1990 a 2009; RESULTADOS: Houve um incremento temporal no número de artigos publicados. Esses artigos enfocaram, principalmente, na produção pesqueira e impactos ambientais; CONCLUSÃO: Os estudos de tanques rede abordaram, principalmente, produção pesqueira, entretanto, as questões ambientais também foram importantes nesta recente atividade humana. Os decisores políticos devem considerar ambos os lados da moeda, ou seja, benefícios e impactos ambientais da produção pesqueira, antes de regular esta atividade.

  18. Status of fish broodstock management and seed production in Bangladesh

    OpenAIRE

    Amin, M.N.

    2005-01-01

    The study was conducted with the broad objectives to assess the existing situation of broodstock management and fish seed production in private fish seed farms in Bangladesh. The data were collected from 100 private hatcheries and 40 nurseries in seven upazilas under four districts. There was no shed in forty hatcheries and the owners faced many problems. Brood fish ponds were found suitable for rearing brood fish. About 66% of the hatchery owners collected brood fish from their own ponds and...

  19. Dynamic Strategies for Yaw and Induction Control of Wind Farms Based on Large-Eddy Simulation and Optimization

    Directory of Open Access Journals (Sweden)

    Wim Munters

    2018-01-01

    Full Text Available In wind farms, wakes originating from upstream turbines cause reduced energy extraction and increased loading variability in downstream rows. The prospect of mitigating these detrimental effects through coordinated controllers at the wind-farm level has fueled a multitude of research efforts in wind-farm control. The main strategies in wind-farm control are to influence the velocity deficits in the wake by deviating from locally optimal axial induction setpoints on the one hand, and steering wakes away from downstream rows through yaw misalignment on the other hand. The current work investigates dynamic induction and yaw control of individual turbines for wind-farm power maximization in large-eddy simulations. To this end, receding-horizon optimal control techniques combined with continuous adjoint gradient evaluations are used. We study a 4 × 4 aligned wind farm, and find that for this farm layout yaw control is more effective than induction control, both for uniform and turbulent inflow conditions. Analysis of optimal yaw controls leads to the definition of two simplified yaw control strategies, in which wake meandering and wake redirection are exploited respectively. Furthermore it is found that dynamic yawing provides significant benefits over static yaw control in turbulent flow environments, whereas this is not the case for uniform inflow. Finally, the potential of combining overinductive axial induction control with yaw control is shown, with power gains that approximate the sum of those achieved by each control strategy separately.

  20. The unique functioning of a pre-Columbian Amazonian floodplain fishery.

    Science.gov (United States)

    Blatrix, Rumsaïs; Roux, Bruno; Béarez, Philippe; Prestes-Carneiro, Gabriela; Amaya, Marcelo; Aramayo, Jose Luis; Rodrigues, Leonor; Lombardo, Umberto; Iriarte, Jose; de Souza, Jonas Gregorio; Robinson, Mark; Bernard, Cyril; Pouilly, Marc; Durécu, Mélisse; Huchzermeyer, Carl F; Kalebe, Mashuta; Ovando, Alex; McKey, Doyle

    2018-04-16

    Archaeology provides few examples of large-scale fisheries at the frontier between catching and farming of fish. We analysed the spatial organization of earthen embankments to infer the functioning of a landscape-level pre-Columbian Amazonian fishery that was based on capture of out-migrating fish after reproduction in seasonal floodplains. Long earthen weirs cross floodplains. We showed that weirs bear successive V-shaped features (termed 'Vs' for the sake of brevity) pointing downstream for outflowing water and that ponds are associated with Vs, the V often forming the pond's downstream wall. How Vs channelled fish into ponds cannot be explained simply by hydraulics, because Vs surprisingly lack fishways, where, in other weirs, traps capture fish borne by current flowing through these gaps. We suggest that when water was still high enough to flow over the weir, out-migrating bottom-hugging fish followed current downstream into Vs. Finding deeper, slower-moving water, they remained. Receding water further concentrated fish in ponds. The pond served as the trap, and this function shaped pond design. Weir-fishing and pond-fishing are both practiced in African floodplains today. In combining the two, this pre-Columbian system appears unique in the world.

  1. Impact of sustainable feeds on omega-3 long-chain fatty acid levels in farmed Atlantic salmon, 2006-2015.

    Science.gov (United States)

    Sprague, M; Dick, J R; Tocher, D R

    2016-02-22

    As the global population and its demand for seafood increases more of our fish will come from aquaculture. Farmed Atlantic salmon are a global commodity and, as an oily fish, contain a rich source of the health promoting long-chain omega-3 fatty acids, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Replacing the traditional finite marine ingredients, fishmeal and fish oil, in farmed salmon diets with sustainable alternatives of terrestrial origin, devoid of EPA and DHA, presents a significant challenge for the aquaculture industry. By comparing the fatty acid composition of over 3,000 Scottish Atlantic salmon farmed between 2006 and 2015, we find that terrestrial fatty acids have significantly increased alongside a decrease in EPA and DHA levels. Consequently, the nutritional value of the final product is compromised requiring double portion sizes, as compared to 2006, in order to satisfy recommended EPA + DHA intake levels endorsed by health advisory organisations. Nevertheless, farmed Scottish salmon still delivers more EPA + DHA than most other fish species and all terrestrial livestock. Our findings highlight the global shortfall of EPA and DHA and the implications this has for the human consumer and examines the potential of microalgae and genetically modified crops as future sources of these important fatty acids.

  2. Accumulation of selenium in aquatic systems downstream of a uranium mining operation in northern Saskatchewan, Canada

    International Nuclear Information System (INIS)

    Muscatello, J.R.; Belknap, A.M.; Janz, D.M.

    2008-01-01

    The objective of this study was to investigate the accumulation of selenium in lakes downstream of a uranium mine operation in northern Saskatchewan, Canada. Selenium concentrations in sediment and biota were elevated in exposure areas even though water concentrations were low (<5 μg/L). The pattern (from smallest to largest) of selenium accumulation was: periphyton < plankton and filterer invertebrates < detritivore and predator invertebrates < small bodied (forage) fish and predatory fish. Biomagnification of selenium resulted in an approximately 1.5-6 fold increase in the selenium content between plankton, invertebrates and forage fish. However, no biomagnification was observed between forage fish and predatory fish. Selenium content in organisms from exposure areas exceeded the proposed 3-11 μg/g (dry weight) dietary toxicity threshold for fish, suggesting that the selenium released into these aquatic systems has the potential to bioaccumulate and reach levels that could impair fish reproduction. - Selenium bioaccumulation patterns in a north temperate, cold water aquatic ecosystem were similar to those reported from warm water systems

  3. Modelization of a large wind farm, considering the modification of the atmospheric boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, A; Gomez-Elvira, R [Univ. Politecnica de Madrid, Mecanica de Fluidos, E.T.S.I. Industriales, Madrid (Spain); Frandsen, S; Larsen, S E [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A method is presented to adapt existing models of wind farms to very large ones that may affect the whole planetary boundary layer. An internal boundary layer is considered that starts developing at the leading edge of the farm until it reaches, sufficiently far downstream, the top of the planetary boundary layer, and a new equilibrium region is reached. The wind farm is simulated by an artificial roughness that is function of the turbine spacing, drag and height. From this model the flow conditions are calculated at a certain reference height and then are used as boundary conditions for a numerical code used to model a wind farm. Three-dimensional effects are considered by applying appropriate conditions at the sides of the farm. Calculations are carried out to estimate the energy production in large wind farms, and it is found that additional losses due to modification of the planetary boundary layer may be of importance for wind farms of size larger than about 100 km. (au)

  4. Factors influencing the marketing of fresh fish in Ogun State, Nigeria ...

    African Journals Online (AJOL)

    Factors influencing the marketing of fresh fish in Ogun State, Nigeria. ... The market prices of Clarias spp. ranged between □250 □400/Kg and the farmers were mostly patronized by retailers. Fish farm ... EMAIL FULL TEXT EMAIL FULL TEXT

  5. A piscicultura e o ambiente: o uso de alimentos ambientalmente corretos em piscicultura Fish farming and the environment: the use of environmental friendly feeds in fish culture

    Directory of Open Access Journals (Sweden)

    José Eurico Possebon Cyrino

    2010-07-01

    Full Text Available Embora a ciência da nutrição de peixes esteja longe de estabelecer um padrão geral de exigências nutricionais, a necessidade de desenvolvimento de alimentos de baixo impacto poluente há muito faz parte da agenda das comunidades científica e empresarial internacional da aqüicultura. Não só é absolutamente possível formular alimentos ambientalmente corretos, como é necessário modelar a formulação destes alimentos. Porém, é necessária absoluta acurácia para atender formulações espécie-específicas, considerando-se as interações da biologia e fisiologia nutricional das espécies com os alimentos e com as variações abióticas do meio. O conhecimento disponível sobre as mais de 200 espécies de peixe produzidas comercialmente no mundo é ainda incipiente e os sistemas de produção de peixe, nos diferentes regimes de exploração, estão implantados em todas as condições ecológicas possíveis. Neste cenário, produzir rações ambientalmente corretas é, senão impossível, pelo menos muito difícil e depende da ação coordenada e positiva de produtores, indústria da alimentação, agências regulatórias, e instituições de ensino e pesquisa para definir os parâmetros necessários à consecução deste objetivo.Although fish nutrition science is far from establishing general standards of nutritional requirements, the need for developing low impact feeds has long been included in the agenda of aquaculture's international scientific and business communities of. Not only is absolutely possible to formulate environmental friendly feeds, as it is necessary modeling the formulation of these feeds. However, it is necessary higher accuracy to develop species-specific formulations, considering interactions of the biology and nutritional physiology of the species with the feedstuffs and variations of abiotic environment. The knowledge on more than 200 species of commercially farmed fish is still incipient and fish production

  6. Total mercury levels in commercial fish species from Italian fishery and aquaculture.

    Science.gov (United States)

    Di Lena, Gabriella; Casini, Irene; Caproni, Roberto; Fusari, Andrea; Orban, Elena

    2017-06-01

    Total mercury levels were measured in 42 commercial fish species caught off the Central Adriatic and Tyrrhenian coasts of Italy and in 6 aquaculture species. The study on wild fish covered species differing in living habitat and trophic level. The study on farmed fish covered marine and freshwater species from intensive and extensive aquaculture and their feed. Mercury levels were analysed by thermal decomposition-amalgamation-atomic absorption spectrophotometry. Total mercury concentrations in the muscle of wild fish showed a high variability among species (0.025-2.20 mg kg -1 wet weight). The lowest levels were detected in low trophic-level demersal and pelagic-neritic fish and in young individuals of high trophic-level species. Levels exceeding the European Commission limits were found in large-size specimens of high trophic-level pelagic and demersal species. Fish from intensive farming showed low levels of total mercury (0.008-0.251 mg kg -1 ). Fish from extensive rearing showed variable contamination levels, depending on the area of provenience. An estimation of the human intake of mercury associated to the consumption of the studied fish and its comparison with the tolerable weekly intake is provided.

  7. Safety on North Carolina and Kentucky trout farms.

    Science.gov (United States)

    Ogunsanya, T J; Durborow, R M; Myers, M L; Cole, H P; Thompson, S L

    2011-01-01

    The objective of this study was to identify and describe work-related safety hazards, injuries, and near-injury events (close calls) that occurred on trout farms in North Carolina and Kentucky. An interview instrument was used to collect information on occupational hazards, injuries, and near-injury events that resulted from work-related activities. Trout farmers reported occupational hazards including falling live tank lids, slippery surfaces on hauling trucks, lifting strains, falls from raceway walls and walkways, needlesticks while vaccinating fish, allergies, hypothermia/drowning, falls from cranes, chemical exposure, fire/explosions related to oxygen exposure, and electrical contact with overhead power lines. This study also reports solutions suggested by farm safety researchers or used by farmers to prevent the safety hazards found on trout farms.

  8. Distribution patterns of fish assemblages in an Eastern Mediterranean intermittent river

    Directory of Open Access Journals (Sweden)

    Vardakas L.

    2015-01-01

    Full Text Available The distribution patterns of fish assemblages within streams can provide insights for river type classifications and may warrant specific conservation actions. However, there is limited knowledge of how fish assemblages assort along a longitudinal axis in Mediterranean intermittent streams. Patterns in spatial and temporal distribution of fish communities were analysed in a Mediterranean intermittent river (Evrotas River located in Southern Greece, hosting three endemic range restricted species of high conservation concern, during the period 2007−2009, with 80% of the river’s total length desiccating in the 2007 and 2008 droughts. The general trend was an increase in fish density and species richness along an upstream-downstream gradient. Fish assemblages from upstream to downstream were characterized by a decrease of the most rheophilic species (Squalius keadicus and an increase of the most stagnophilic species (Tropidophoxinellus spartiaticus. Three river segments, characterized by a high degree of homogeneity were delineated. Habitat and environmental preferences for the studied fish species were identified, with elevation and low flowing habitats being the most important environmental factors affecting fish distribution patterns. The current study provides evidence that even in an intermittent river an assemblage pattern following a longitudinal gradient can be identified, mainly due to the lack of instream barriers that allows recolonization after flow resumption.

  9. A Conceptual Framework for Agri-Food Tourism as an Eco-Innovation Strategy in Small Farms

    Directory of Open Access Journals (Sweden)

    Shang-Yu Liu

    2017-09-01

    Full Text Available The proposed conceptual framework explores how small-scale farms can combine agricultural products and tourism into an eco-innovation strategy. This paper presents a case study conducted on a family-run farm within the territory of the Paiwan tribal community of the North Dawu Mountain situated in the Central Mountain Range of Taiwan. The area has become an important coffee-farming region since the Japanese colonial period between 1895 and 1945. For many years, most of the indigenous farmers of the area have cultivated varieties of coffee plants using traditional, non-commercial methods, such as a single-sale channel. The small-scale farmer implements an integrated approach that systematically optimizes supply chain relationships to improve both the upstream and downstream sides of agri-food tourism services. The upstream element of agri-food tourism, for example, can be adjusted to employ organic or “natural” farming methods that allow small-scale farmers to secure an “organic” certification. Based on this approach, a small farm is gradually transformed into a type of educational institution that can demonstrate to customers the methods for farming high-quality organic coffee while also attracting tourists of various backgrounds to experience the downstream components of agri-food tourism in a recreational setting. This case study highlights how a particular small-scale farmer plays an important role in attracting other tribal farmers to engage in sustainable practices that help preserve cultural, social, and environmental systems while also presenting agri-food tourism as a brand identity.

  10. The Gut Microbiota of Marine Fish

    Science.gov (United States)

    Egerton, Sian; Culloty, Sarah; Whooley, Jason; Stanton, Catherine; Ross, R. Paul

    2018-01-01

    The body of work relating to the gut microbiota of fish is dwarfed by that on humans and mammals. However, it is a field that has had historical interest and has grown significantly along with the expansion of the aquaculture industry and developments in microbiome research. Research is now moving quickly in this field. Much recent focus has been on nutritional manipulation and modification of the gut microbiota to meet the needs of fish farming, while trying to maintain host health and welfare. However, the diversity amongst fish means that baseline data from wild fish and a clear understanding of the role that specific gut microbiota play is still lacking. We review here the factors shaping marine fish gut microbiota and highlight gaps in the research. PMID:29780377

  11. From Farming to Fishing: Marine Resource Conservation and a New ...

    African Journals Online (AJOL)

    This paper examines the arrival of a new group of fishermen on the Kenyan coast and what this has meant for the state of fishery resources. It reviews four subject areas: access and the number of fishermen; the fishermen's identity; the choice of fishing gear; and the fishing grounds selected. Data were collected from a small ...

  12. Passage of fish larvae and eggs through the Funil, Itutinga and Camargos Reservoirs on the upper Rio Grande (Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Mineo Suzuki

    Full Text Available The objective of this study was to evaluate the passage of fish eggs and larvae through the Funil, Itutinga and Camargos Reservoirs, located in the upper Rio Grande basin, Minas Gerais, Brazil. Samples were taken downstream and upstream of the dams using a conical ichthyoplankton net and were collected every two weeks, twice per sampling day, between November 2008 and March 2009. Although eggs and larvae were abundant immediately upstream of the reservoirs, no ichthyoplankton were captured immediately downstream of the dams, possibly indicating that eggs and larvae do not pass through the reservoirs. The arrival of ichthyoplankton in the reservoirs without its effective passage downstream makes the survival of these eggs and larvae unlikely. Furthermore, this lack of downstream movement may compromise the recruitment of species to downstream stretches, especially in the case of the Funil Reservoir (because of the presence of a fish pass in this dam. We emphasize that the fish lift operation at the Funil Dam must be carefully assessed, considering not only its efficiency but also its short- and long-term effects on the recruitment of migratory fish species from the river.

  13. Blockage of migration routes by dam construction: can migratory fish find alternative routes?

    Directory of Open Access Journals (Sweden)

    Rosimeire Ribeiro Antonio

    Full Text Available The present study explored the interaction between the upriver migration of fish and the blockage of their migration routes by dam construction. Specifically, we studied (i the capacity of migratory fish to locate alternative routes in the presence of an obstacle, and (ii the behavior of the fish after they were artificially transferred to the reservoir. With the use of the mark-recapture technique (tagging, the study was carried out near Porto Primavera Dam (UHE Engenheiro Sérgio Motta between 1994 and 1999, a period prior to the closure of the floodgates and the installation and operation of the fish pass facilities. The fish were caught in the dam forebay downstream, marked with LEA type tags, and released upstream (5113 individuals; 14 species and downstream (1491; 12 from the dam. The recaptures were carried out by local professional and amateur fishermen. A total of 188 individuals (2.8% were recaptured, mostly the curimba Prochilodus lineatus. Nearly half of the recaptures downstream occurred in tributaries, especially in the Paranapanema River, indicating that in the presence of an obstacle the fish are able to locate alternative migration routes. The remainder stayed in the main channel of the Paraná River, at a mean distance of less than 50 km from the release point. Of the fish released upriver from the dam, approximately half were recaptured downriver. Although the river was only partly dammed, the movement of the fish downriver suggests that they became disoriented after being transferred. Those that remained upriver avoided the reservoir and moved, rather rapidly, toward the lotic stretches farther upstream. From these results it is clear that, in the course of the decision process in installing fish passes, it is necessary to take into account the existence of spawning and nursery areas downriver and upriver from the reservoir.

  14. OCCURRENCE OF INFECTIOUS PANCREATIC NECROSIS VIRUS (IPNV IN FARMED RAINBOW TROUT (ONCHORHYNCHUS MYKISS IN KOSOVO

    Directory of Open Access Journals (Sweden)

    Agim Rexhepi

    2013-10-01

    Full Text Available This article describes the research carried out for the detection of viruses responsible for VHS, IHN and IPN diseases in farmed rainbow trout (Oncorhynchus mykiss in Kosovo for the three-year period between 2006 and 2008. Losses are often reported in trout fingerlings, but no virus has ever been isolated in the rainbow trout in Kosovo. A research project was carried out to determine the occurrence of VHSV, IHNV & IPNV from the samples of fish tissue and ovarian fluids from mature broodfish. In total, 467 fishes from 113 (pools in 10 rainbow trout aquaculture facilities were screened. Laboratory analysis was performed at the TGD (Tiergesundheitsdienst Bayern e. V laboratory in Germany using the biomolecular method of RT-PCR and nested-PCR. The Infectious Pancreatic Necrosis virus was detected in seven trout farms, and prevalence from total samples (pools was 11.5 %. This is the first research and report for IPN virus diagnosis in farmed rainbow trout fry, on-growing fish and broodfish in Kosovo. Keywords: Rainbow trout, viral diseases, IPN, RT-PCR, nested PCR

  15. Viral haemorrhagic septicaemia virus in marine fish and its implications for fish farming - a review

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Olesen, Niels Jørgen; Mellergaard, Stig

    2005-01-01

    Viral haemorrhagic septicaemia virus (VHSV) has, in recent decades, been isolated from an increasing number of free-living marine fish species. So far, it has been isolated from at least 48 fish species from the northern hemisphere, including North America, Asia and Europe, and fifteen different...... marine fish show no to low pathogenicity to rainbow trout and Atlantic salmon, although several are pathogenic for turbot. Marine VHSV isolates are so far serologically indistinguishable from freshwater isolates. Genotyping based on VHSV G- and N-genes reveals four groups indicating the geographical...... origin of the isolates, with one group representing traditional European freshwater isolates and isolates of north European marine origin, a second group of marine isolates from the Baltic Sea, a third group of isolates from the North Sea, and a group representing North American isolates. Examples...

  16. Modelling Infectious Hematopoietic Necrosis Virus Dispersion from Marine Salmon Farms in the Discovery Islands, British Columbia, Canada.

    Directory of Open Access Journals (Sweden)

    Michael G G Foreman

    Full Text Available Finite volume ocean circulation and particle tracking models are used to simulate water-borne transmission of infectious hematopoietic necrosis virus (IHNV among Atlantic salmon (Salmo salar farms in the Discovery Islands region of British Columbia, Canada. Historical simulations for April and July 2010 are carried out to demonstrate the seasonal impact of river discharge, wind, ultra-violet (UV radiation, and heat flux conditions on near-surface currents, viral dispersion and survival. Numerical particles released from infected farm fish in accordance with IHNV shedding rates estimated through laboratory experiments are dispersed by model oceanic flows. Viral particles are inactivated by ambient UV radiation levels and by the natural microbial community at rates derived through laboratory studies. Viral concentration maps showing temporal and spatial changes are produced and combined with lab-determined minimum infectious dosages to estimate the infective connectivity among farms. Results demonstrate that neighbouring naïve farms can become exposed to IHNV via water-borne transport from an IHNV diseased farm, with a higher risk in April than July, and that many events in the sequence of farm outbreaks in 2001-2002 are consistent with higher risks in our farm connectivity matrix. Applications to other diseases, transfers between farmed and wild fish, and the effect of vaccinations are also discussed.

  17. Status and Habitat Requirements of White Sturgeon Populations in the Columbia River Downstream from McNary Dam, 1989-1990 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Nigro, Anthony A. (Oregon Department of Fish and Wildlife, Portland, OR)

    1990-09-01

    We report on our progress from April 1989 through March 1990 on determining the status and habitat requirements of white sturgeon populations in the Columbia River downstream from McNary Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW), Washington Department of Fisheries (WDF), US Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS). Study objectives addressed by each agency are to describe the life history and population dynamics of subadults and adults between Bonneville and McNary dams and evaluate the need and identify potential methods for protecting, mitigating and enhancing populations downstream from McNary Dam, to describe the white sturgeon recreational fishery between Bonneville and McNary dams, describe reproductive and early life history characteristics downstream from Bonneville Dam and describe life history and population dynamics of subadults and adults downstream from Bonneville Dam, to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available between Bonneville and McNary dams, and to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available downstream from Bonneville Dam. Our approach is to work concurrently downstream and upstream from Bonneville Dam. Upstream from Bonneville Dam we began work in the Dalles Reservoir in 1987 and expanded efforts to Bonneville Reservoir in 1988 and John Day Reservoir in 1989. Highlights from this work is also included. 47 refs., 33 figs., 66 tabs.

  18. 78 FR 66683 - Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit

    Science.gov (United States)

    2013-11-06

    ... the Western Pacific; Special Coral Reef Ecosystem Fishing Permit AGENCY: National Marine Fisheries... special coral reef ecosystem fishing permit. SUMMARY: NMFS issued a Special Coral Reef Ecosystem Fishing Permit that authorizes Kampachi Farms, LLC, to culture and harvest a coral reef ecosystem management unit...

  19. Installaton of a fish migration channel for spawning at Itaipu

    International Nuclear Information System (INIS)

    Borghetti, J.R.; Perez Chena, D.; Nogueira, S.V.G.

    1993-01-01

    The objective of installing a fish migration channel for spawning at the Itaipu hydroelectric station on the Parana river between Brazil and Paraguay is to improve fish recovery downstream from the dam. Preliminary data from the first phase has proved the efficiency of an experimental project, with the entry and ascendancy of fish in a migration channel ladder. These data now provide the technical basis for implementation of the complementary spawning channel stage. (author)

  20. Metal and metallothionein content in tissues from wild and farmed Anguilla anguilla at commercial size.

    Science.gov (United States)

    Ureña, R; Peri, S; del Ramo, J; Torreblanca, A

    2007-05-01

    Metallothionein and metal content (Cd, Zn, Hg, Cu, Fe, Pb and Mn) were determined in various organs of commercially available eel (Anguilla anguilla) of similar size obtained from a local farm and from The Albufera Lake in Valencia (Spain). Farmed fish showed statistically significant higher Cd concentrations in liver and kidney whereas wild individuals had higher levels of Pb in blood and Zn in kidney. Significant positive correlations were found between metallothionein and Cd in kidney of farmed eel and between metallothionein and Cu in liver of wild ones. No statistically significant differences were found between the two populations in the concentration of any of the metals analyzed in muscle and in all instances these levels were lower than the limits established by the Spanish legislation for fish destined for human consumption.

  1. ENVIRONMENTAL IMPACT OF FISH FARMING IN FLOATING CAGES IN ISLA ARENA, CAMPECHE

    Directory of Open Access Journals (Sweden)

    Yadira Silva-Cruz

    2011-11-01

    Full Text Available Mariculture is the cultivation of marine species of commercial importance. This activity has intensified in recent decades due to the need for food production. The present study evaluated the impact of Rachycentron canadum (Cobia and Sciaenops ocellatus (Red Drum farming in floating cages along the coasts of Campeche, Mexico. The impact of this mariculture system was evaluated through the physicochemical analysis of the sediment from underneath the cages and the analysis of the quality of the water from the farming area. Results showed high concentrations of nitrogen (> 0.5 % and organic matter (> 80 %, both in the farming area and in the control sites. The concentration of fine sediment showed no spatial or temporal changes. There were no detectable concentrations of nitrites, nitrates, ammonium and phosphates in the water, in a range of 0.1 to 100 mg L-1. The impact caused by this farming system appeared to be non significant, at least in the area of study, due to the constant movement of the water caused by ocean currents which, very likely, carried the waste from the cages to other places.

  2. Weight-length relationship, condition factor and blood parameters of farmed Cichla temensis Humboldt, 1821 (Cichlidae in central Amazon

    Directory of Open Access Journals (Sweden)

    Marcos Tavares-Dias

    Full Text Available Farming of native carnivore fish species has drawn attention due to their promising use in aquaculture. Among these species, tucunaré of the genus Cichla stand out, them being of high economical interest for sport fishing and Amazon's industry of ornamental fish. The present study describes the weight-length relationship (WLR, relative condition factor (Kn, red blood cell parameters, thrombocytes and leukocytes count of Cichla temensis Humboldt, 1821, farmed in central Amazon. Fish that underwent food training during fingerling culture received extruded ration containing 45% of crude protein during fattening, and had Kn with values from 0.925-1.199, which indicated good health condition during the culture. The equation obtained from the WLR was W = 0.0073Lt3.1435, indicating an isometric growth, which is the desirable for fish of fish farm. Red blood cell counts, total thrombocyte and leukocyte counts, hematocrit, hemoglobin concentration, mean corpuscular volume (MCV, concentration of mean corpuscular hemoglobin (MCHC, lymphocytes, monocytes and neutrophils had intra-specific variation. A significant (p<0.001 positive correlation of the red blood cells number with the hemoglobin concentration and hematocrit was found. These are the first sets of blood parameters for C. temensis and could be used as reference for comparison in further studies to evaluate the health status of this fish in different environments, because assessment of these parameters may be used as quick tool for diagnosing diseases, stress and malnutrition.

  3. Yersiniosis outbreak in rainbow trout at fish farm in Oromia Regional ...

    African Journals Online (AJOL)

    Ethiopia's physical environment and availability of agricultural residues ... Trout Fish Farmers Private Limited Company has established a commercial trout fish ... different organs were closely observed in situ for the presence of visible macro-.

  4. Infauna monitoring Horns Rev offshore wind farm. Annual state report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

    2005-04-15

    higher in the wind farm area indicating that the potential decrease in predation pressure from birds contributed to increasing differences between the densities of their favoured prey. Bird observations showed predominant foraging activity outside the wind farm area. An indirect effect of increased pressure from fish predation due to a ban against fishing inside the wind farm area is considered negligible as the fish attracted to the turbine foundations mainly forage on the foundations. In general, the abundance of the most common species increased in the wind farm area between 2003 and 2004 whereas the reference area remained unchanged from 2003 to 2004. (au)

  5. Infauna monitoring Horns Rev offshore wind farm. Annual status report 2004

    International Nuclear Information System (INIS)

    Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

    2005-04-01

    higher in the wind farm area indicating that the potential decrease in predation pressure from birds contributed to increasing differences between the densities of their favoured prey. Bird observations showed predominant foraging activity outside the wind farm area. An indirect effect of increased pressure from fish predation due to a ban against fishing inside the wind farm area is considered negligible as the fish attracted to the turbine foundations mainly forage on the foundations. In general, the abundance of the most common species increased in the wind farm area between 2003 and 2004 whereas the reference area remained unchanged from 2003 to 2004. (au)

  6. Socio-economic status of fish farmers in Phalga Local Government ...

    African Journals Online (AJOL)

    Survey of socio-economic status of fish farmers in Phalga Local Government Area, Rivers State, Nigeria was carried out to evaluate the trend, structures, operations, management of fish farms and the level of acceptability of new technologies. The Local Government Area was divided into eight zones, and each zone was ...

  7. Fish Culture Technologies in Cross River State, Nigeria | Offem ...

    African Journals Online (AJOL)

    O. niloticus was most common in all zones accounting for 91.6 percent, Heteroclarias culture was practiced only in Zone C. Fish culture in earthen ponds was most common in Zone A and accounted for 40.9%, while most farms (33.3%) in Zone C raised their fish in concrete ponds. Flow through system was more adopted in ...

  8. A NEW MODULA TYPO-DIMENSIONAL, CONSTRUCTIVE AND FUNCTIONAL CONCEPT OF VIVA DON EXPERT® FLOATABLE FISH CAGES FOR INTENSIVE AQUACULTURE IN INLAND WATERS

    OpenAIRE

    D. ONEA; V. CRISTEA

    2009-01-01

    This scientific work presents succinct information about the trials which takes place between 2005-2009 in Constanta (fish farm Canalul Rompetrol). This trials includes the fish farming in cages and leads to finishing off and elaboration of a new modular typo-dimensional, constructive and functional concept of viva don Expert® floatable fish cages for intensive aquaculture in inland waters from Romania like an efficient solution for the qualitative and quantitative increase of local fish prod...

  9. Characterisation of aroma-active and off-odour compounds in German rainbow trout (Oncorhynchus mykiss). Part II: Case of fish meat and skin from earthen-ponds farming.

    Science.gov (United States)

    Mahmoud, Mohamed Ahmed Abbas; Buettner, Andrea

    2017-10-01

    Odorous molecules in earthen-ponds rainbow trout aquaculture farming in Germany were investigated with a special focus on musty-earthy off-odorants. To this aim, fish meat and skin were extracted using solvent-assisted flavour evaporation (SAFE) and were mildly concentrated; extracts were subsequently analysed by means of one- and two-dimensional high-resolution gas chromatography coupled with mass spectrometry and olfactometry (GC-MS/O and 2D-HRGC-MS/O). Aroma extract dilution analysis (AEDA) of the solvent extracts revealed the presence of 76 odorants of which 75 were successfully identified. Thereby, rotundone (black pepper) is described for the first time as an odour-active substance in fish. Moreover, a series of compounds is described for the first time in German aquaculture rainbow trout fish, including, amongst others, (E,Z,Z)-2,4,7-tridecatrienal, (E)-4,5-epoxy-(E)-2-decenal, 4-ethyloctanoic acid, 3-methylindole (skatole), d-limonene, and indole. The analytical findings were further compared to sensory evaluation of the samples, and previously obtained data on the respective aquacultural water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Benthic monitoring of salmon farms in Norway using foraminiferal metabarcoding

    DEFF Research Database (Denmark)

    Pawlowski, Jan; Esling, Philippe; Lejzerowicz, Franck

    2016-01-01

    The rapid growth of the salmon industry necessitates the development of fast and accurate tools to assess its environmental impact. Macrobenthic monitoring is commonly used to measure the impact of organic enrichment associated with salmon farm activities. However, classical benthic monitoring can...... of macrofauna-based benthic monitoring. Here, we tested the application of foraminiferal metabarcoding to benthic monitoring of salmon farms in Norway. We analysed 140 samples of eDNA and environmental RNA (eRNA) extracted from surface sediment samples collected at 4 salmon farming sites in Norway. We sequenced...... of Foraminifera as bioindicators of organic enrichment associated with salmon farming. The foraminiferal diversity increased with the distance to fish cages, and metabarcoding provides an assessment of the ecological quality comparable to the morphological analyses. The foraminiferal metabarcoding approach...

  11. Can the Global Adoption of Genetically Improved Farmed Fish Increase Beyond 10%, and How?

    Directory of Open Access Journals (Sweden)

    Ingrid Olesen

    2015-05-01

    Full Text Available The annual production from global aquaculture has increased rapidly from 2.6 million tons or 3.9% of the total supply of fish, shellfish and mollusks in 1970, to 66.7 million tons or 42.2% in 2012, while capture fisheries have more or less leveled out at about 90 million tons per year since the turn of the century. Consequently, the future seafood supply is likely to depend on a further increase of aquaculture production. Unlike terrestrial animal farming, less than 10% of the aquaculture production comes from domesticated and selectively bred farm stocks. This situation has substantial consequences in terms of poorer resource efficiency, poorer product quality and poorer animal welfare. The history of biological and technical challenges when establishing selective breeding programs for aquaculture is discussed, and it is concluded that most aquaculture species may now be domesticated and improved by selection. However, the adoption of selective breeding in aquaculture is progressing slowly. This paper reports on a study carried out in 2012 to identify key issues to address in promoting the development of genetically improved aquaculture stocks. The study involved semi structured interviews of 34 respondents from different sectors of the aquaculture society in East and Southeast Asia, where 76% of the global aquaculture production is located. Based on the interviews and literature review, three key factors are identified: (i long-term public commitment is often needed for financial support of the breeding nucleus operation (at least during the first five to ten generations of selection; (ii training at all levels (from government officers and university staff to breeding nucleus and hatchery operators, as well as farmers; and (iii development of appropriate business models for benefit sharing between the breeding, multiplier and grow-out operators (whether being public, cooperative or private operations. The public support should be invested in

  12. Heavy metal contamination of water and fish in peri-urban dams ...

    African Journals Online (AJOL)

    Heavy metals were measured in water, sediment and fish in dams located downstream of effluent discharge zones in Bulawayo and were compared to those in a pristine upstream dam. Water conductivity indicated pollution of downstream dams. Levels of lead (0.13 – 0.28 ppm) and cadmium (0.02 – 0.06 ppm) in water from ...

  13. Worm-it: converting organic wastes into sustainable fish feed by using aquatic worms

    NARCIS (Netherlands)

    Elissen, H.J.H.; Hendrickx, T.L.G.; Temmink, H.; Laarhoven, B.; Buisman, C.J.N.

    2015-01-01

    Due to overfishing and the use of one-third of wild fish catches for feeding farmed fish and livestock, there is a strong need for alternative sources of suitable proteins and lipids in fish feeds. Small freshwater worms of the species Lumbriculus variegatus can be such a source based on their high

  14. Isotopic evidence for dead fish maintenance of Florida red tides, with implications for coastal fisheries over both source regions of the West Florida shelf and within downstream waters of the South Atlantic Bight

    Science.gov (United States)

    Walsh, J. J.; Weisberg, R. H.; Lenes, J. M.; Chen, F. R.; Dieterle, D. A.; Zheng, L.; Carder, K. L.; Vargo, G. A.; Havens, J. A.; Peebles, E.; Hollander, D. J.; He, R.; Heil, C. A.; Mahmoudi, B.; Landsberg, J. H.

    2009-01-01

    Toxic Florida red tides of the dinoflagellate Kareniabrevis have downstream consequences of 500-1000 km spatial extent. Fish stocks, shellfish beds, and harmful algal blooms of similar species occupy the same continental shelf waters of the southeastern United States, amounting to economic losses of more than 25 million dollars in some years. Under the aegis of the Center for Prediction of Red tides, we are now developing coupled biophysical models of the conditions that lead to red tides and impacted coastal fisheries, from the Florida Panhandle to Cape Hatteras. Here, a nitrogen isotope budget of the coastal food web of the West Florida shelf (WFS) and the downstream South Atlantic Bight (SAB) reaffirms that diazotrophs are the initial nutrient source for onset of red tides and now identifies clupeid fish as the major recycled nutrient source for their maintenance. The recent isotope budget of WFS and SAB coastal waters during 1998-2001 indicates that since prehistoric times of Timacua Indian settlements along the Georgia coast during 1075, ∼50% of the nutrients required for large red tides of >1 μg chl l -1 of K.brevis have been derived from nitrogen-fixers, with the other half from decomposing dead sardines and herrings. During 2001, >90% of the harvest of WFS clupeids was by large ichthyotoxic red tides of >10 μg chl l -1 of K.brevis, rather than by fishermen. After onset of the usual red tides in summer of 2006 and 2007, the simulated subsequent fall exports of Florida red tides in September 2007 to North Carolina shelf waters replicate observations of just ∼1 μg chl l -1 on the WFS that year. In contrast, the earlier red tides of >10 μg chl l -1 left behind off West Florida during 2006, with less physical export, are instead 10-fold larger than those of 2007. Earlier, 55 fish kills were associated with these coastal red tides during September 2006, between Tampa and Naples. Yet, only six fish kills were reported there in September 2007. With little

  15. Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines

    International Nuclear Information System (INIS)

    San Diego-McGlone, Maria Lourdes; Azanza, Rhodora V.; Villanoy, Cesar L.; Jacinto, Gil S.

    2008-01-01

    The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995-2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was <2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time

  16. 78 FR 49258 - Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit

    Science.gov (United States)

    2013-08-13

    ... the Western Pacific; Special Coral Reef Ecosystem Fishing Permit AGENCY: National Marine Fisheries... Reef Ecosystem Fishing Permit that would authorize Kampachi Farms, LLC, to culture and harvest a coral reef ecosystem management unit fish species in a floating pen moored about 5.5 nm off the west coast of...

  17. OWEZ pelagic fish, progress report and progression after T1

    NARCIS (Netherlands)

    Ybema, M.S.; Gloe, D.; Lambers, R.H.L.

    2009-01-01

    This report presents the current status of pelagic fish research in the Offshore Windfarm Egmond aan Zee (OWEZ) after having finalized the T0 baseline survey in 2003 and the T1 survey after construction of the wind farm in 2007. The T0 study indicated a highly dynamic pelagic fish community along

  18. Risk assessment of residual DDTs in freshwater and marine fish cultivated around the Pearl River Delta, China.

    Science.gov (United States)

    Leung, S Y; Kwok, C K; Nie, X P; Cheung, K C; Wong, M H

    2010-02-01

    Six species of freshwater fish collected from 10 fishponds in Shunde and Zhongshan, China, four species of marine fishes collected from different mariculture farms [four in Hong Kong (Tung Lung Chau, Ma Wan, Cheung Chau and Kat O) and two in mainland China (Daya Bay and Shenzhen)] together with feed (both trash fish and commercial pellets) and sediment were analyzed for DDTs. Total DDTs in freshwater fish flesh decreased in the order of: carnivores [1742 microg/kg lipid weight (l.w.)] > herbivores (165 microg/kg, l.w.) > omnivores (42.5 microg/kg, l.w.), with the highest concentration detected in mandarin fish (Siniperca chuatsi) (2641 microg/kg, l.w.). For marine fish, snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides) collected in Ma Wan contained elevated levels of total DDTs (2590 and 2034 microg/kg l.w., respectively). Trash fish used in both freshwater and marine fish farms contained significantly higher levels (86.5-641 microg/kg l.w.) (p trash fish should not be used for fish culture in order to lower the level of residual DDTs in fish muscle.

  19. Evidence for serial discontinuity in the fish community of a heavily impounded river

    Science.gov (United States)

    Miranda, Leandro E.; Dembkowski, D.J.

    2016-01-01

    In the Tennessee River, USA, we examined lengthwise patterns in fish community structure and species richness within and among nine reservoirs organized in sequence and connected through navigational locks. Within reservoirs, the riverine, transition and lacustrine zones supported distinct, although overlapping, nearshore fish assemblages; differences were also reflected in measures of species richness. Spatial patterns were most apparent for rheophilic species, which increased in species richness and representation upstream within each reservoir and downstream across the chain of reservoirs. This pattern resembled a sawtooth wave, with the amplitude of the wave peaking in the riverine zone below each dam, and progressively higher wave amplitude developing downstream in the reservoir chain. The observed sawtooth pattern supports the serial discontinuity concept in that the continuity of the riverine fish community is interrupted by the lacustrine conditions created behind each dam. Upstream within each reservoir, and downstream in the chain of reservoirs, habitat characteristics become more riverine. To promote sustainability of rheophilic fishes and maintain biodiversity in impounded rivers, conservation plans could emphasize maintenance and preservation of riverine environments of the reservoir's upper reaches, while remaining cognizant of the broader basin trends that provide opportunities for a lengthwise array of conservation and management policy. 

  20. Who cares about fish welfare?

    DEFF Research Database (Denmark)

    Ellingsen, Kristian; Grimsrud, Kristine; Nielsen, Hanne Marie

    2015-01-01

    . Research limitations/implications – In this study willingness to pay is measured using a hypothetical choice experiment. Values people express as citizens, however, may not accurately predict true consumer behaviour. This is generally referred to as “citizen-consumer duality” and may have affected...... about the appropriate way to pay for better welfare standards in fish production. Design/methodology/approach – On the basis of two focus group sessions, a survey questionnaire was developed and distributed to a representative sample of 2,147 Norwegian households via e-mail. Findings – Results showed...... the results. Practical implications – The study shows that there is a national market for welfare-assured fish products, but education initiatives focusing on fish farming and fish welfare issues would further influence the attitudes and purchasing habits of Norwegian consumers. Originality/value – Although...

  1. Sensory quality and onset of rigor mortis for farmed turbot under various post slaughter conditions

    NARCIS (Netherlands)

    Schelvis-Smit, A.A.M.; Veldman, M.; Kruijt, A.W.; Vis, van de J.W.

    2006-01-01

    As is the case for most farmed fish, the production of turbot is targeting the fresh markets established in Europe and Asia. Usually turbot is packed whole, dead or alive and transported directly to the market. On some occasions the fish are bled and gutted prior to delivery.

  2. The Application of Traits-Based Assessment Approaches to Estimate the Effects of Hydroelectric Turbine Passage on Fish Populations

    Energy Technology Data Exchange (ETDEWEB)

    Cada, Glenn F [ORNL; Schweizer, Peter E [ORNL

    2012-04-01

    One of the most important environmental issues facing the hydropower industry is the adverse impact of hydroelectric projects on downstream fish passage. Fish that migrate long distances as part of their life cycle include not only important diadromous species (such as salmon, shads, and eels) but also strictly freshwater species. The hydropower reservoirs that downstream-moving fish encounter differ greatly from free-flowing rivers. Many of the environmental changes that occur in a reservoir (altered water temperature and transparency, decreased flow velocities, increased predation) can reduce survival. Upon reaching the dam, downstream-migrating fish may suffer increased mortality as they pass through the turbines, spillways and other bypasses, or turbulent tailraces. Downstream from the dam, insufficient environmental flow releases may slow downstream fish passage rates or decrease survival. There is a need to refine our understanding of the relative importance of causative factors that contribute to turbine passage mortality (e.g., strike, pressure changes, turbulence) so that turbine design efforts can focus on mitigating the most damaging components. Further, present knowledge of the effectiveness of turbine improvements is based on studies of only a few species (mainly salmon and American shad). These data may not be representative of turbine passage effects for the hundreds of other fish species that are susceptible to downstream passage at hydroelectric projects. For example, there are over 900 species of fish in the United States. In Brazil there are an estimated 3,000 freshwater fish species, of which 30% are believed to be migratory (Viana et al. 2011). Worldwide, there are some 14,000 freshwater fish species (Magurran 2009), of which significant numbers are susceptible to hydropower impacts. By comparison, in a compilation of fish entrainment and turbine survival studies from over 100 hydroelectric projects in the United States, Winchell et al. (2000

  3. Survival and growth of fish (Lates calcarifer under integrated mangrove-aquaculture and open-aquaculture systems

    Directory of Open Access Journals (Sweden)

    Shanmugaarasu Venkatachalam

    2018-02-01

    Full Text Available The potential use of mangrove swamp for fish farming industry is not clearly known. Therefore, current study was conducted to assess the growth performance of the Asian Seabass, Lates calcarifer cultivated in integrated mangrove-aquaculture system (IMAS and open aquaculture system without mangroves (OAS. Fish survival and biomass production were higher by 11% and 12.5% respectively in the IMAS than those in the OAS. The fish growth performance was higher in monsoon than that in other seasons. It was in association with water quality parameters such as, high levels of DO, chlorophylls-a,b, nitrate-N, DOC, TOC; low levels of light intensity, temperature (air, water, SPM, chlorophyll-c, nitrite-N, ammonia, total phosphate, reactive silicate, and POC; as well with moderate salinity. The water quality seemed to be favourable for growth and survival of the fish. Therefore, integrating the mangroves with fish farming of the Asian seabass is beneficial for better fish survival and biomass production.

  4. Effects of pond draining on biodiversity and water quality of farm ponds.

    Science.gov (United States)

    Usio, Nisikawa; Imada, Miho; Nakagawa, Megumi; Akasaka, Munemitsu; Takamura, Noriko

    2013-12-01

    Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large-scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond-management practices, pond physicochemistry, and surrounding land use. The results of boosted regression-tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo. © 2013 Society for Conservation Biology.

  5. Random and systematic sampling error when hooking fish to monitor skin fluke (Benedenia seriolae) and gill fluke (Zeuxapta seriolae) burden in Australian farmed yellowtail kingfish (Seriola lalandi).

    Science.gov (United States)

    Fensham, J R; Bubner, E; D'Antignana, T; Landos, M; Caraguel, C G B

    2018-05-01

    The Australian farmed yellowtail kingfish (Seriola lalandi, YTK) industry monitor skin fluke (Benedenia seriolae) and gill fluke (Zeuxapta seriolae) burden by pooling the fluke count of 10 hooked YTK. The random and systematic error of this sampling strategy was evaluated to assess potential impact on treatment decisions. Fluke abundance (fluke count per fish) in a study cage (estimated 30,502 fish) was assessed five times using the current sampling protocol and its repeatability was estimated the repeatability coefficient (CR) and the coefficient of variation (CV). Individual body weight, fork length, fluke abundance, prevalence, intensity (fluke count per infested fish) and density (fluke count per Kg of fish) were compared between 100 hooked and 100 seined YTK (assumed representative of the entire population) to estimate potential selection bias. Depending on the fluke species and age category, CR (expected difference in parasite count between 2 sampling iterations) ranged from 0.78 to 114 flukes per fish. Capturing YTK by hooking increased the selection of fish of a weight and length in the lowest 5th percentile of the cage (RR = 5.75, 95% CI: 2.06-16.03, P-value = 0.0001). These lower end YTK had on average an extra 31 juveniles and 6 adults Z. seriolae per Kg of fish and an extra 3 juvenile and 0.4 adult B. seriolae per Kg of fish, compared to the rest of the cage population (P-value sampling towards the smallest and most heavily infested fish in the population, resulting in poor repeatability (more variability amongst sampled fish) and an overestimation of parasite burden in the population. In this particular commercial situation these finding supported that health management program, where the finding of an underestimation of parasite burden could provide a production impact on the study population. In instances where fish populations and parasite burdens are more homogenous, sampling error may be less severe. Sampling error when capturing fish

  6. Fit fish. Energy-efficient gas management for aquaculture; Fitness fuer Fische. Energieeffizientes Gasemanagement fuer Aquakulturen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2011-07-01

    Fish farming is increasingly taking place on shore, using large inland tanks and pools. This conserves natural fish stocks and protects marine ecosystems. Linde engineers have developed a new, highly energy-efficient oxygenation system to ensure that salmon and other popular fish can thrive in the tank. (orig.)

  7. Presence of Piscirickettsia salmonis in farmed trout (Oncorhynchus mykiss) in Junin, Peru

    OpenAIRE

    Yunis A., Jefferson; Anicama D., Jahir; Manchego S., Alberto; Sandoval C., Nieves

    2015-01-01

    This study aimed to determine the possible presence ofPiscirickettsia salmonis in farmed rainbow trout (Oncorhynchus mykiss) in the Mantaro river basin, Junin, Peru, by the indirect inmunofluorescence test (IFAT). Kidney and spleen samples were collected from 180 trout from three fish farms. All samples resulted negative to P. salmonis; however, some individuals showed clinical sings of disease as skin ulcer, melanosis, abdominal swelling and exophthalmoses. Also, in the internal organs was f...

  8. Cooperative wind turbine control for maximizing wind farm power using sequential convex programming

    International Nuclear Information System (INIS)

    Park, Jinkyoo; Law, Kincho H.

    2015-01-01

    Highlights: • The continuous wake model describes well the wake profile behind a wind turbine. • The wind farm power function describes well the power production of a wind farm. • Cooperative control increases the wind farm power efficiency by 7.3% in average. • SCP can be employed to efficiently optimize the control actions of wind turbines. - Abstract: This paper describes the use of a cooperative wind farm control approach to improve the power production of a wind farm. The power production by a downstream wind turbine can decrease significantly due to reduced wind speed caused by the upstream wind turbines, thereby lowering the overall wind farm power production efficiency. In spite of the interactions among the wind turbines, the conventional (greedy) wind turbine control strategy tries to maximize the power of each individual wind turbine by controlling its yaw angle, its blade pitch angle and its generator torque. To maximize the overall wind farm power production while taking the wake interference into account, this study employs a cooperative control strategy. We first derive the wind farm power as a differentiable function of the control actions for the wind turbines in a wind farm. The wind farm power function is then maximized using sequential convex programming (SCP) to determine the optimum coordinated control actions for the wind turbines. Using an example wind farm site and available wind data, we show how the cooperative control strategy improves the power production of the wind farm

  9. Recovery of ovary size, follicle cell apoptosis, and HSP70 expression in fish exposed to bleached pulp mill effluent

    Energy Technology Data Exchange (ETDEWEB)

    Janz, D. M.; Weber, L. P. [Oklahoma State Univ., Stillwater, OK (United States); McMaster, M. E.; Munkittrrick, K. R. [Environment Canada, Burlington, ON (Canada); Van Der Kraak, G. [Guelph Univ., Dept. of Zoology, ON (Canada)

    2001-03-01

    Apoptosis of granulosa cells that provide hormonal support for the oocyte is the normal mechanism by which atresia ( reduced ovarian size, decreased fecundity, delayed sexual maturation, alterations in plasma sex steroid levels, etc) occurs in mammals, birds and possibly fish. The objective of this study is to determine ovarian cell apoptosis, gonadosomatic index (GSI) and heat shock protein (HSP70) expression during the growth stage of ovarian development in white sucker fish in order to compare samples of fish collected upstream and downstream of a bleached kraft pulp mill in Ontario. Fish for the study were collected in two different years, before and after the pulp mill undertook a number of improvements to eliminate the release of process chemicals. Results showed a 3.4-fold increase in ovarian cell apoptosis in growing white sucker collected four km downstream of the bleached kraft pulp mill in 1996 (before the improvements) compared to fish collected from upstream sources. The elevated ovarian cell apoptosis was associated with significant reduction in gonadosomatic index in fish collected downstream. There were no differences in ovarian cell apoptosis or gonadosomatic index between fish collected upstream and four km downstream of the mill in September 1998 (after the improvements.) Based on the results, it may be concluded that chronic stimulation of ovarian cell apoptosis by certain components of bleached kraft pulp mill effluents represents an important cellular mechanism for reducing the size of ovaries and other related reproductive responses in female fish exposed to these effluents. Although the specific effluent components are not known, the improvements undertaken between 1996 and 1998 resulted in significant enough recovery of these responses to justify the belief in a cause-effect relationship. 32 refs., 1 tab., 2 figs.

  10. Food wastes as fish feeds for polyculture of low-trophic-level fish: bioaccumulation and health risk assessments of heavy metals in the cultured fish.

    Science.gov (United States)

    Cheng, Zhang; Lam, Cheung-Lung; Mo, Wing-Yin; Nie, Xiang-Ping; Choi, Wai-Ming; Man, Yu-Bon; Wong, Ming-Hung

    2016-04-01

    The major purpose of this study was to use different types of food wastes which serve as the major sources of protein to replace the fish meal used in fish feeds to produce quality fish. Two types of food waste-based feed pellets FW A (with cereals) and FW B (with cereals and meat products) and the commercial feed Jinfeng® were used to culture fingerlings of three low-trophic-level fish species: bighead carp, grass carp, and mud carp (in the ratio of 1:3:1) for 1 year period in the Sha Tau Kok Organic Farm in Hong Kong. Heavy metal concentrations in all of the fish species fed with food waste pellets and commercial pellets in Sha Tau Kok fish ponds were all below the local and international maximum permissible levels in food. Health risk assessments indicated that human consumption of the fish fed with food waste feed pellets was safe for the Hong Kong residents. The present results revealed that recycling of food waste for cultivating low-trophic-level fish (mainly herbivores and detritus feeders) is feasible, and at the same time will ease the disposal pressure of food waste, a common problem of densely populated cities like Hong Kong.

  11. Describing cross-cultural differences in the consumption of fish: Data from a consumer survey in five European countries

    DEFF Research Database (Denmark)

    Honkanen, Pirjo; Toften, Kjell; Olsen, Svein Ottar

    also reports consumption frequency for wild versus farmed fish. However, it seems that many consumers are not aware if the fish they buy are wild or farmed. Secondly, this study also investigated similarities and differences in shopping habits. Supermarkets and fishmongers were the most often used......The objective of this paper is to explore eating and shopping habits related to fish across five European countries. A cross sectional consumer survey was carried out in Belgium, Denmark, Netherlands, Poland, and Spain. A total sample of 4800 consumers was obtained, and the sample...... of fish across countries was 1.5 times a week. Spain had by far the highest frequency of fish consumption with almost three times a week, followed by Denmark with 1.4 times a week. The consumption of fish was lowest in the Netherlands. On average, about 80 % of all fish meals were consumed at home. While...

  12. Persistence and stability of fish community structure in a southwest New York stream

    Science.gov (United States)

    Hansen, Michael J.; Ramm, Carl W.

    1994-01-01

    We used multivariate and nonparametric statistics to examine persistence and stability of fish species in the upper 43 km of French Creek, New York. Species occurred in upstream and downstream groups in 1937 that persisted in 1979. However, the downstream group expanded its range in the drainage from 1937 to 1979 at the expense of the upstream group. A dam prevented further upstream expansion of the downstream group. Ranks of species abundances were stable, as tests of group similarity were significant. The abundances and distributions of benthic species were stable across seven sampling dates in 1980 despite several floods and repeated removals by sampling that could have altered community structure. We conclude that the fish community in French Creek persisted and was stable over the 42-yr interval, 1937-1979, and that abundances of benthic species were stable in summer 1980.

  13. Effects of a surface oriented travelling screen and water abstraction practices on downstream migrating Salmonidae smolts in a lowland stream

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Aarestrup, Kim; Deacon, Michael G.

    2010-01-01

    Downstream migration of immature salmonids (smolts) may be associated with severe mortalities in anthropogenically altered channels. In Pacific salmon, several investigations have suggested the use of the dominating surface orientation of smolts to improve fish by-pass structures in large and dee...

  14. Variability of CO2 emissions during the rearing cycle of a semi-intensive shrimp farm in a mangrove coastal zone (New Caledonia).

    Science.gov (United States)

    Aimé, Joanne; Allenbach, Michel; Bourgeois, Carine; Léopold, Audrey; Jacotot, Adrien; Vinh, Truong Van; Nho, Nguyen Thanh; Patrona, Luc Della; Marchand, Cyril

    2018-04-01

    In New Caledonia, shrimp ponds are built not on cleared mangroves but on salt flats behind the mangroves. The objectives of this study were to determine the variability of CO 2 fluxes from a semi-intensive shrimp pond during active and non-active periods of the farm and to determine the carbon dynamics from the upstream tidal creek to the downstream creek, which receives the farm's effluents. CO 2 emissions from the active pond were estimated at 11.1 ± 5.26 mmol CO 2  m -2  d -1 . By modifying the hydrodynamics of the creeks, farm practices also influenced CO 2 emissions from both the upstream and downstream creeks. After tillage, all the organic carbon deposited at the pond bottom during the active period was mineralized, resulting in CO 2 emissions to the atmosphere estimated at 7.9 TCO 2  ha -1 . Therefore, shrimp farming is an anthropogenic source of CO 2 to the atmosphere, but suitable and optimized rearing practices limit these emissions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Ultra-high performance liquid chromatography with fluorescence detection following salting-out assisted liquid-liquid extraction for the analysis of benzimidazole residues in farm fish samples.

    Science.gov (United States)

    Tejada-Casado, Carmen; Lara, Francisco J; García-Campaña, Ana M; Del Olmo-Iruela, Monsalud

    2018-03-30

    Ultra-high performance liquid chromatography (UHPLC) coupled with fluorescence detection (FL) has been proposed for the first time to determine thirteen benzimidazoles (BZs) in farmed fish samples. In order to optimize the chromatographic separation, parameters such as mobile phase composition and flow rate were carefully studied, establishing a gradient mode with a mobile phase consisted of water (solvent A) and acetonitrile (solvent B) at a flow rate of 0.4 mL/min. The separation was performed on a Zorbax Eclipse Plus RRHD C 18 column (50 × 2.1 mm, 1.8 μm), involving a total analysis time lower than 12 min. Salting-out assisted liquid-liquid extraction (SALLE) was applied as sample treatment to different types of farmed fish (trout, sea bream and sea bass). To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized including the amount of sample, type and volume of the extraction solvent, and the nature and amount of the salt used. Characterization of the method in terms of performance characteristics was carried out, obtaining satisfactory results for the linearity (R 2  ≥ 0.997), repeatability (RSD ≤ 6.1%), reproducibility (RSD ≤ 10.8%) and recoveries (R ≥ 79%; RSD ≤ 7.8%). Detection limits between 0.04-29.9 μg kg -1 were obtained, demonstrating the applicability of this fast, simple and environmentally friendly method. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Current Status of the Use of Antibiotics and the Antimicrobial Resistance in the Chilean Salmon Farms

    Directory of Open Access Journals (Sweden)

    Claudio D. Miranda

    2018-06-01

    Full Text Available The Chilean salmon industry has undergone a rapid development making the country the world’s second largest producer of farmed salmon, but this growth has been accompanied by an intensive use of antibiotics. This overuse has become so significant that Chilean salmon aquaculture currently has one of the highest rates of antibiotic consumption per ton of harvested fish in the world. This review has focused on discussing use of antibiotics and current status of scientific knowledge regarding to incidence of antimicrobial resistance and associated genes in the Chilean salmonid farms. Over recent years there has been a consistent increase in the amount of antimicrobials used by Chilean salmonid farms, from 143.2 tons in 2010 to 382.5 tons in 2016. During 2016, Chilean companies utilized approximately 0.53 kg of antibiotics per ton of harvested salmon, 363.4 tons (95% were used in marine farms, and 19.1 tons (5% in freshwater farms dedicated to smolt production. Florfenicol and oxytetracycline were by far the most frequently used antibiotics during 2016 (82.5 and 16.8%, respectively, mainly being used to treat Piscirickettsia salmonis, currently considered the main bacterial threat to this industry. However, the increasing development of this industry in Chile, as well as the intensive use of antimicrobials, has not been accompanied by the necessary scientific research needed to understand the impact of the intensive use of antibiotics in this industry. Over the last two decades several studies assessing antimicrobial resistance and the resistome in the freshwater and marine environment impacted by salmon farming have been conducted, but information on the ecological and environmental consequences of antibiotic use in fish farming is still scarce. In addition, studies reporting the antimicrobial susceptibility of bacterial pathogens, mainly P. salmonis, have been developed, but a high number of these studies were aimed at setting their

  17. The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems

    OpenAIRE

    Nhan, D.K.

    2007-01-01

    In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a farm, which allows to improve resource use efficiency and income while reducing environmental impacts. This study monitored and analyzed water use in and nutrient flows through ponds that are part of an IAA-farming system. Th...

  18. Preliminary studies in rice-fish culture in a rainfed lowland ecology ...

    African Journals Online (AJOL)

    Preliminary studies in rice-fish culture in a rainfed lowland ecology in Ghana. PKA Dartey, RK Bam, J Ofori. Abstract. Mixed farms of rice and fish are yet to receive attention in Ghana, despite lowland rice being grown under inundation in most areas nationwide. In a preliminary study, Nile tilapia (Oreochromis niloticus) was ...

  19. Effects of exotic fish farms on bird communities in lake and marine ecosystems

    Science.gov (United States)

    Jiménez, Jaime E.; Arriagada, Aldo M.; Fontúrbel, Francisco E.; Camus, Patricio A.; Ávila-Thieme, M. Isidora

    2013-08-01

    Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.

  20. Environmental impact of sea bass cage farming in the north Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Domenico Lanari

    2010-01-01

    Full Text Available The main objective of the research was to reduce the organic and nutrient load under the net pen fish farms. An exper- iment was conducted to study the effects of artificial barriers fixed under a set of sea cages in order to reduce the envi- ronmental impact. The artificial barriers were made of four submerged galvanized steel pipes coated with plastic and placed on the sea floor (10 m depth in the Trieste gulf. The experimental design was as follows: control (C, cages with barriers (B, cages without barriers (WB. Measurements were taken on the surface as well as at 4 and 8m of depth. The trial lasted from the end of June 2000 to December 2001. Water quality parameters were not significantly influenced by the fish cages. Surface samples were characterised by lower levels of salinity and higher levels of oxygen and nitrate compared to those taken at 4 and 8 m. The artificial barriers favoured the establishment of a rich epiphytic fauna that took advantage of the presence of organic matter derived from fish cages. The two species Nucula nucleusand Neanthes caudataand the total bacterial counts were identified as potential indicators of pollution under the fish cage farms.

  1. Estimating the wake deflection downstream of a wind turbine in different atmospheric stabilities: an LES study

    Directory of Open Access Journals (Sweden)

    L. Vollmer

    2016-09-01

    Full Text Available An intentional yaw misalignment of wind turbines is currently discussed as one possibility to increase the overall energy yield of wind farms. The idea behind this control is to decrease wake losses of downstream turbines by altering the wake trajectory of the controlled upwind turbines. For an application of such an operational control, precise knowledge about the inflow wind conditions, the magnitude of wake deflection by a yawed turbine and the propagation of the wake is crucial. The dependency of the wake deflection on the ambient wind conditions as well as the uncertainty of its trajectory are not sufficiently covered in current wind farm control models. In this study we analyze multiple sources that contribute to the uncertainty of the estimation of the wake deflection downstream of yawed wind turbines in different ambient wind conditions. We find that the wake shapes and the magnitude of deflection differ in the three evaluated atmospheric boundary layers of neutral, stable and unstable thermal stability. Uncertainty in the wake deflection estimation increases for smaller temporal averaging intervals. We also consider the choice of the method to define the wake center as a source of uncertainty as it modifies the result. The variance of the wake deflection estimation increases with decreasing atmospheric stability. Control of the wake position in a highly convective environment is therefore not recommended.

  2. The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems

    NARCIS (Netherlands)

    Nhan, D.K.

    2007-01-01

    In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a farm, which allows to

  3. Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining

    Science.gov (United States)

    Hitt, Nathaniel P.; Chambers, Douglas B.

    2014-01-01

    Mountaintop mining (MTM) affects chemical, physical, and hydrological properties of receiving streams, but the long-term consequences for fish-assemblage structure and function are poorly understood. We sampled stream fish assemblages using electrofishing techniques in MTM exposure sites and reference sites within the Guyandotte River basin, USA, during 2010–2011. We calculated indices of taxonomic diversity (species richness, abundance, Shannon diversity) and functional diversity (functional richness, functional evenness, functional divergence) to compare exposure and reference assemblages between seasons (spring and autumn) and across years (1999–2011). We based temporal comparisons on 2 sites that were sampled during 1999–2001 by Stauffer and Ferreri (2002). Exposure assemblages had lower taxonomic and functional diversity than reference assemblages or simulated assemblages that accounted for random variation. Differences in taxonomic composition between reference and exposure assemblages were associated with conductivity and aqueous Se concentrations. Exposure assemblages had fewer species, lower abundances, and less biomass than reference assemblages across years and seasons. Green Sunfish (Lepomis cyanellus) and Creek Chub (Semotilus atromaculatus) became numerically dominant in exposure assemblages over time because of their persistence and losses of other taxa. In contrast, species richness increased over time in reference assemblages, a result that may indicate recovery from drought. Mean individual biomass increased as fish density decreased and most obligate invertivores were apparently extirpated at MTM exposure sites. Effects of MTM were not related to physical-habitat conditions but were associated with water-quality variables, which may limit quality and availability of benthic macroinvertebrate prey. Simulations revealed effects of MTM that could not be attributed to random variation in fish assemblage structure.

  4. Copper in the sediment and sea surface microlayer near a fallowed, open-net fish farm.

    Science.gov (United States)

    Loucks, Ronald H; Smith, Ruth E; Fisher, Clyde V; Fisher, E Brian

    2012-09-01

    Sediment and sea surface microlayer samples near an open-net salmon farm in Nova Scotia, were analysed for copper. Copper is a constituent of the feed and is an active ingredient of anti-foulants. The salmon farm was placed in fallow after 15 years of production. Sampling was pursued over 27 months. Elevated copper concentrations in the sediments indicated the farm site as a source. Bubble flotation due to gas-emitting sediments from eutrophication is a likely process for accumulating copper in the sea surface microlayer at enriched concentrations. Elevated and enriched concentrations in the sea surface microlayer over distance from the farm site led, as a result of wind-drift, to an enlarged farm footprint. The levels of copper in both sediments and sea surface microlayer exceeded guidelines for protection of marine life. Over the 27 months period, copper levels persisted in the sediments and decreased gradually in the sea surface microlayer. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. affect rice in integrated rice-fish culture in Lake Victoria Basin, Kenya?

    African Journals Online (AJOL)

    AGHOGHO A

    Rice field ecology and fish culture - an overview. Hydrobiologia 259:91-113. Fernando CH, Halwart M (2000). Fish farming in irrigation systems. Fisheries Management and Ecol. 7:45-54. Frei M, Razzak MA, Hossain MM, Ochme M, Dewan S, Becker K. (2007). Performance of common carp, Cyprinus carpio L. and Nile.

  6. Effect of fish and oil nature on frying process and nutritional product quality

    OpenAIRE

    Ansorena, D. (Diana); Guembe, A. (Ainhoa); Mendizabal, T. (Tatiana); Astiasarán, I. (Iciar)

    2010-01-01

    The modifications on a lean fish (cod-Gadus morhua) and a fatty fish (farmed salmon-Salmo salar) after the application of pan-frying using 2 types of oil with different lipid profile (extra virgin olive oil and sunflower oil) was the aim of this study. Fat content and total energetic value increased significantly after the frying process only in the lean fish, without relevant changes in the fatty fish. Extra virgin olive oil led to a higher fat absorption rate than sunflower oil in both fish...

  7. Case Study on Model Factorial Analysis of Turnover Depending on the Structure of Production Sold in a Farm from South-Eastern Development Region

    Directory of Open Access Journals (Sweden)

    Carmen Georgeta Nicolae

    2010-10-01

    Full Text Available changes in economic and financial phenomenon. Such a study is required arguments for a set of managementmeasures geared towards improving work farms analyzed. The evolution over time in turnover was based on knownstatistical models. The period considered in the study farm is 2007-2008, and turnover analysis refers to the businessof delivering fresh and frozen fish. Following the study found that modification of fish production during the twoyears the level of the average price of delivery and, ultimately, turnover of the holding. Thus in 2007, fresh fishrepresented 56% of the total quantity of fish delivered, in 2008 the share of fresh fish delivered was only 45.5% ofthe total production of fish delivered. This change in structure has helped to increase overall turnover resulting fromthe fish market in the year 2008 consisted of turnover from the sales of fresh fish 43.7%, 56.3% difference is that offish delivered frozen.

  8. Native and exotic fishes in a Patagonian reservoir with rainbow trout cage culture: spatial and trophic resource use

    Directory of Open Access Journals (Sweden)

    Nabaes Jodar Diego N.

    2017-01-01

    Full Text Available Although the interactions of exotic salmonids with native Patagonian fishes are well known, little is known about the ecology and impact of farmed fish escapees. Salmonid production in Argentina is largely concentrated in the Alicurá reservoir in north Patagonia, where fish community studies have been scarce. Here, we assess and compare the spatial distribution, body size–condition and diet of the different fish species in this reservoir. Strong vertical segregation was observed between exotic rainbow trout Oncorhynchus mykiss (both escapees and wild, dominating the littoral zone, and native Percichthys trucha which dominate the medium and deep strata. Low piscivory–benthivory and high zooplanktivory were observed for rainbow trout, both traits being uncommon at a regional scale. Escaped farmed rainbow trout (ERT diet included abundant indigestible items along with wild prey. Higher body condition of P. trucha close to farms, as well as the regionally unprecedented high incidence of Daphnia sp. in the guts of all the species suggest that farm nutrient discharges have had significant impacts. Finally, the high body condition of ERT, together with their wild food diet and the long dispersal distance observed, demonstrate post-escape success, drawing our attention to potential upstream dispersion affecting the biodiversity and fisheries of Patagonian rivers and lakes.

  9. Beta-haemolytic streptococci in farmed Nile tilapia, Oreochromis niloticus, from Sullana-Piura, Peru

    Directory of Open Access Journals (Sweden)

    Yessica Ortega A

    2017-01-01

    Full Text Available Objective. This investigation aimed to study the presence of Streptococcus spp. in tilapia (Oreochromis niloticus from fish farm located in Sullana-Piura, Peru. Materials and methods. 150 fish with clinical signs of streptococcal disease were sampled, and the bacterium isolation was performed on blood agar, correlated to histopathological lesions description and molecular confirmation by real-time PCR. Results. The necropsy revealed exophthalmia, hyphema, congestion and/or haemorrhagic meninges, ascites, splenomegaly, hepatomegaly and diffuse haemorrhagic zones throughout the body. 102 isolated positives (54 tilapias to Streptococcus spp. were identified in the microbiological analysis (prevalence of 26%, the brain was the organ with the highest percentage of this bacteria (34.31%, and 19 isolates were beta-haemolytic (18.63% with prevalence of 10.12%. Fish beta-haemolytic streptococci presented epicarditis, perisplenitis and chronic meningitis, panophthalmitis, coagulative necrosis of skeletal muscle and granulomas formation. In the confirmatory test by real-time PCR, any positive tilapia to S. iniae was obtained. The results were analysed using a stochastic simulation of beta distribution using @Risk program uncertainty, reporting an average prevalence of 0.66% in sick tilapias. Conclusions. The analysed fishes were positive to bacteria of the genus Streptococcus, which confirms its presence in the fish farm. However, 19 isolates were beta-haemolytic, and the presence of S. iniae was not positive to the limit prevalence of 2.7% in real-time PCR.

  10. Prevalence and Antimicrobial Resistance Profile of Listeria Species Isolated from Farmed and On-Sale Rainbow Trout ( Oncorhynchus mykiss) in Western Iran.

    Science.gov (United States)

    Rezai, Ramin; Ahmadi, Elham; Salimi, Behnam

    2018-05-01

    Listeria species are important foodborne pathogens, among which L. monocytogenes and L. ivanovii cause human listeriosis. The purpose of this study was to evaluate the incidence and antimicrobial resistance profiles of Listeria species in farmed and on-sale rainbow trout ( Oncorhynchus mykiss) in Kurdistan province, western Iran. A total of 240 fresh rainbow trout fish (120 samples from farms and 120 samples from retail outlets) were collected and analyzed phenotypically for the presence of Listeria. All Listeria isolates were differentiated with molecular techniques, and L. monocytogenes strains were identified to serotype. The antibiotic susceptibility of all Listeria isolates also was determined. Among the 240 samples, 86 (35.83%) were contaminated with Listeria: 32 samples of farmed fish and 54 samples of on-sale fish. The prevalence among the 240 samples was 9.16% (22 samples) for L. monocytogenes, 6.66% (16 samples) for L. ivanovii, 3.75% (9 samples) for L. welshimeri, 4.99% (12 samples) for L. grayi, 7.5% (18 samples) for L. innocua, and 3.75% (9 samples) for L. seeligeri. The prevalences of the human pathogenic strains L. monocytogenes and L. ivanovii were 4.16% (5 samples) and 14.16% (17 samples) in farmed fish and 5.83% (7 samples) and 7.5% (9 samples) in on-sale fish, respectively. Of the 22 L. monocytogenes isolates, 15, 3, and 4 were identified as serotypes 4b, 1/2a, and 1/2b, respectively. The highest rates of antibiotic resistance among the 86 Listeria isolates was observed against tetracycline (62.79% of all isolates), enrofloxacin (56.97%), and ciprofloxacin (38.37%). Very high resistance was also detected against penicillin (36.04%) and ampicillin (34.88%). These results highlight the potential public health threat posed by fish contaminated with Listeria species, including L. monocytogenes, in the west of Iran. Regular monitoring of Listeria contamination, upgrading of sanitary conditions in the fish industry, and prudent use of antibiotics is

  11. The emerging farmed fish species meagre (Argyrosomus regius): how culinary treatment affects nutrients and contaminants concentration and associated benefit-risk balance.

    Science.gov (United States)

    Costa, Sara; Afonso, Cláudia; Bandarra, Narcisa Maria; Gueifão, Sandra; Castanheira, Isabel; Carvalho, Maria Luísa; Cardoso, Carlos; Nunes, Maria Leonor

    2013-10-01

    The effect of cooking methods (boiling, grilling, and roasting) on the proximate and mineral composition, contaminants concentration and fatty acids profile was evaluated aiming to understand the benefits and risks associated to the consumption of the emerging farmed fish meagre (Argyrosomus regius). All the treatments led to lower moisture content. After grilling and roasting, the SFA, MUFA and PUFA contents increased. There was no degradation of EPA and DHA during the culinary processes. Significant retention of minerals in grilled and roasted meagre samples was registered. For Pb and Cd there were no concentration differences between culinary treatments and regarding raw fish. Whereas As level was higher in grilled meagre, total Hg and Me-Hg values were augmented in grilled and roasted meagre. The consumption of meagre is advisable due to the low and healthy fat, high selenium and protein content. Grilling would be the best culinary treatment due to the retention of protein, EPA, DHA and minerals. But as the risk of ingestion of Me-Hg content also increases, based on the risk assessment, intake should not exceed two weekly meals, provided that no other important Me-Hg food source is present in the diet. Otherwise, even this maximum threshold should be lower. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Wake Measurements in ECN's Scaled Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wagenaar, J.W.; Schepers, J.G. [ECN Wind Energy, Petten (Netherlands)

    2013-02-15

    In ECN's scaled wind farm the wake evolution is studied in two different situations. A single wake is studied at two different locations downstream of a turbine and a single wake is studied in conjunction with a triple wake. Here, the wake is characterized by the wind speed ratio, the turbulence intensity, the vertical wind speed and the turbulence (an)isotropy. Per situation all wake measurements are taken simultaneously together with the inflow conditions.

  13. Nutritional requirements of freshwater ornamental fish: a review

    Directory of Open Access Journals (Sweden)

    Yohana Velasco-Santamaría

    2011-05-01

    Full Text Available The knowledge of nutritional requirements in ornamental fish species is essential to improve the productive development; however, the nutritional information of these species is scarce and sometimes this information is extrapolated from results obtained from non-ornamental fish species. In ornamental fish, a correct formulation of the diet improve the nutrient digestibility and supply the metabolic needs, reducing the maintenance cost and at the same time the water pollution. Inert food such as meal powder, flakes, milk powder, bovine heart and liver, tubifex worms, as well as live food including Artemia sp., rotifers and Moina have been used extensively in ornamental fish feeding with a diverse range of nutritional values and productive properties. In contrast with farmed fish, skin pigmentation is a mandatory characteristic in ornamental fish and the use of dietary supplements with carotenoids is recommended. The aim of this document is to review the specific nutritional requirements which are indispensable to improve economical and productive potential of freshwater ornamental fish.

  14. Runoff and water-quality characteristics of three Discovery Farms in North Dakota, 2008–16

    Science.gov (United States)

    Galloway, Joel M.; Nustad, Rochelle A.

    2017-12-21

    during only a few large rain events throughout 2009–16. Flow was somewhat continuous at sites E2 and E3 throughout the year during years of increased precipitation, such as in 2010 and 2011. At Dazey farm, annual flow volumes at the most downstream site D3 for 2010–15 ranged from 88 acre-feet (2012) to 12,060 acre-feet (2010). The largest monthly runoff volumes at D1 (most upstream site; combination of data from site D1a [original site] and site D1b [relocated site]) and D3 were in March and April during spring snowmelt runoff and rain events.At Underwood farm, total ammonia and total phosphorus had the highest concentrations at the most upstream site (U1) and decreased sequentially at sites U2 and U3 downstream. Total ammonia and total phosphorus concentrations at the sites for Underwood farm also generally were higher than measured at sites for the Dazey and Embden farms. At Embden farm, nitrate plus nitrite concentrations were lowest at site E1 (surface-water site) and highest at sites E2 and E3 (drainage tile sites). Nitrate plus nitrite concentrations at sites E2 and E3 also were the highest among all the sites at all three farms. Median total nitrate plus nitrite concentrations for sites E1, E2, and E3 were 0.22, 13, and 10 milligrams per liter as nitrogen, respectively. Nutrient concentrations generally were greater at site D1 (most upstream site) compared to site D3 (most downstream site) at Dazey farm. Higher concentrations at site D1, which is farther upstream and closer to potential sources of nutrients, compared to lower concentrations at site D3, which is farther downstream and receives more runoff, indicates that dilution may be the reason concentrations decrease downstream.Annual loads for chloride at all three Underwood sites were the greatest in 2011 and the least in 2012, which coincided with years of the greatest and least annual flow volume, respectively. Total ammonia had a similar pattern at the three sites. Nitrate plus nitrite loads displayed

  15. Physiological Assessment and Behavioral Interaction of Wild and Hatchery Juvenile Salmonids : The Relationship of Fish Size and Growth to Smoltification in Spring Chinook Salmon.

    Energy Technology Data Exchange (ETDEWEB)

    Beckman, Brian R.; Larsen, Donald A.; Lee-Pawlak, Beeda; Dickhoff, Walton W.

    1996-10-01

    Experiments were performed to determine the relative influence of size and growth rate on downstream migratory disposition and physiology in yearling spring chinook salmon (Oncorhynchus tshawtscha) smolts. A group of juvenile chinook salmon was size graded into small and large categories with half the fish in each group reared at an elevated temperature, resulting in four distinct treatment groups: Large Warm (LW), Large Cool (LC), Small Warm (SW), and Small Cool (SC). Fish from warm-water treatment groups displayed significantly higher growth rates than cool-water groups. Fish were tagged and released into a natural creek where downstream movement was monitored. For each of the two releases, fish that migrated past a weir within the first 5 days postrelease had significantly higher spring growth rates than fish that did not migrate within that period. Significant differences in length for the same fish were only found in the second release. Also for the second release, fish from the warm water treatment groups were recovered in higher proportions than fish from cool water groups. The results indicate that increased growth rate in the spring has a positive relation to downstream migratory disposition. Furthermore, there is a relation between smolt size and migration; however, this relation is weaker than that found between growth rate and migration.

  16. Natural coinfection by Streptococcus agalactiae and Francisella noatunensis subsp. orientalis in farmed Nile tilapia (Oreochromis niloticus L.).

    Science.gov (United States)

    Assis, G B N; Tavares, G C; Pereira, F L; Figueiredo, H C P; Leal, C A G

    2017-01-01

    Streptococcus agalactiae and Francisella noatunensis subsp. orientalis (Fno) are important pathogens for farm-raised tilapia worldwide. There are no reports of coinfection caused by S. agalactiae and Fno in fish. This study aimed to determine the aetiology of atypical mortalities in a cage farm of Nile tilapia and to characterize the genetic diversity of the isolates. Fifty-two fish were sampled and subjected to parasitological and bacteriological examination. The S. agalactiae and Fno isolates were genotyped using MLST and REP-PCR, respectively. Whole-genome sequencing was performed to confirm the MLST results. Seven fish were shown coinfected by S. agalactiae and Fno. Chronic hypoxia and a reduction in the water temperature were determined as risk factors for coinfection. Fno isolates were shown clonally related in REP-PCR. The MLST analysis revealed that the S. agalactiae isolates from seven coinfected fish were negative for the glcK gene; however, these were determined to be members of clonal complex CC-552. This is the first description of coinfection by S. agalactiae and Fno in farm-raised Nile tilapia. The coinfection was predisposed by chronic hypoxia and was caused by the main genotypes of S. agalactiae and Fno reported in Brazil. Finally, a new S. agalactiae genotype with glcK gene partially deleted was described. © 2016 John Wiley & Sons Ltd.

  17. Fish on farms combat dietary deficits in Cambodia | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2014-04-11

    Apr 11, 2014 ... The farmers are learning to build and maintain ponds where they raise fish ... In Prey Veng, 5% of children die before their fifth birthday, with about a ... and developing-country researchers together to address the interlocking ...

  18. The influence of fish feed pellets on the stability of seabed sediment: A laboratory flume investigation

    Science.gov (United States)

    Neumeier, Urs; Friend, Patrick L.; Gangelhof, Uffe; Lunding, Jens; Lundkvist, Morten; Bergamasco, Alessandro; Amos, Carl L.; Flindt, Mogens

    2007-11-01

    Superfluous fish food settling below fish farms can have a negative impact on the seabed. To aid in the assessment of this impact a series of flume experiments, designed to mimic seabed conditions below a fish farm, was conducted with the aim of examining the effects of fish pellets on the stability of fine sediments. Artificial beds, with varying quantities of fish pellets incorporated both within the sediment matrix and lying on the sediment surface, were allowed to consolidate for different periods of time ranging from 1 to 10 days, and then subjected to erosion experiments. In flume experiments containing fish pellets, a bacterial biofilm developed at the sediment-water interface after a few days. In the control experiments (no fish pellets), a diatom biofilm caused extensive stabilisation of the surface sediment. The erosion experiments showed that the addition of fish pellets reduced the surface erosion threshold by more than 50%. The stability decrease was more pronounced in the experiments with greater amounts of pellets. Evidence of drag reduction due to high suspended sediment concentration was also observed. This phenomenon is discussed and a correction formula is proposed for the effective shear stress experienced by the bed.

  19. In situ observations of the influence of a large onshore wind farm on near-surface temperature, turbulence intensity and wind speed profiles

    Science.gov (United States)

    Smith, Craig M.; Barthelmie, R. J.; Pryor, S. C.

    2013-09-01

    Observations of wakes from individual wind turbines and a multi-megawatt wind energy installation in the Midwestern US indicate that directly downstream of a turbine (at a distance of 190 m, or 2.4 rotor diameters (D)), there is a clear impact on wind speed and turbulence intensity (TI) throughout the rotor swept area. However, at a downwind distance of 2.1 km (26 D downstream of the closest wind turbine) the wake of the whole wind farm is not evident. There is no significant reduction of hub-height wind speed or increase in TI especially during daytime. Thus, in high turbulence regimes even very large wind installations may have only a modest impact on downstream flow fields. No impact is observable in daytime vertical potential temperature gradients at downwind distances of >2 km, but at night the presence of the wind farm does significantly decrease the vertical gradients of potential temperature (though the profile remains stably stratified), largely by increasing the temperature at 2 m.

  20. In situ observations of the influence of a large onshore wind farm on near-surface temperature, turbulence intensity and wind speed profiles

    International Nuclear Information System (INIS)

    Smith, Craig M; Barthelmie, R J; Pryor, S C

    2013-01-01

    Observations of wakes from individual wind turbines and a multi-megawatt wind energy installation in the Midwestern US indicate that directly downstream of a turbine (at a distance of 190 m, or 2.4 rotor diameters (D)), there is a clear impact on wind speed and turbulence intensity (TI) throughout the rotor swept area. However, at a downwind distance of 2.1 km (26 D downstream of the closest wind turbine) the wake of the whole wind farm is not evident. There is no significant reduction of hub-height wind speed or increase in TI especially during daytime. Thus, in high turbulence regimes even very large wind installations may have only a modest impact on downstream flow fields. No impact is observable in daytime vertical potential temperature gradients at downwind distances of >2 km, but at night the presence of the wind farm does significantly decrease the vertical gradients of potential temperature (though the profile remains stably stratified), largely by increasing the temperature at 2 m. (letter)

  1. Toxic elements in free-living freshwater fish, water and sediments in Poland

    Directory of Open Access Journals (Sweden)

    Szkoda Józef

    2014-12-01

    Full Text Available Samples for analysis were collected from 10 areas, including the major Polish rivers and lakes, with different sources of environmental pollution (industrial, municipal, and farming. The materials was taken from the lakes of Mazury, located in a non-industrialised region, from the Brda River, an area impacted by pig farms, from the lakes of Lipczyno Wielkie/Pomerania, from the Wkra River, an area impacted by poultry farms, from the Dunajec River at the Roznowski Reservoir, from the Vistula River at Cracow and Warsaw, from the Odra River at Wroclaw and the Warta River estuary, and also from Rybnik Power Station Reservoir. Concentrations of Pb, Cd, Hg, and As were analysed in 397 fish muscle and 128 sediment samples using an atomic absorption spectrometry technique. The analytical procedures were covered by a quality assurance programme. It was demonstrated that the average concentrations of lead, cadmium, and arsenic in fish were in the low hundredths and thousandths of a mg/kg and never exceeded permitted limits established for food. Higher values of these elements were found in fish from bodies of water located in the zone of influence of large urban agglomerations, especially the Cracow region. High concentrations of lead and cadmium were also found in Vistula River sediments near Cracow, where the maximum values were 134.10 mg/kg and 21.24 mg/kg dry weight for lead and cadmium respectively. The average concentration of mercury in a predatory fish muscle (0.179 mg/kg was almost twice as high as in the omnivorous fish (0.103 mg/kg. Only a single fish sample exceeded the maximum limit for this metal (0.50 mg/kg and did not present a risk to consumers’ health.

  2. Simulation of Intra- or transboundary surface-water-rights hierarchies using the farm process for MODFLOW-2000

    Science.gov (United States)

    Schmid, W.; Hanson, R.T.

    2007-01-01

    Water-rights driven surface-water allocations for irrigated agriculture can be simulated using the farm process for MODFLOW-2000. This paper describes and develops a model, which simulates routed surface-water deliveries to farms limited by streamflow, equal-appropriation allotments, or a ranked prior-appropriation system. Simulated diversions account for deliveries to all farms along a canal according to their water-rights ranking and for conveyance losses and gains. Simulated minimum streamflow requirements on diversions help guarantee supplies to senior farms located on downstream diverting canals. Prior appropriation can be applied to individual farms or to groups of farms modeled as "virtual farms" representing irrigation districts, irrigated regions in transboundary settings, or natural vegetation habitats. The integrated approach of jointly simulating canal diversions, surface-water deliveries subject to water-rights constraints, and groundwater allocations is verified on numerical experiments based on a realistic, but hypothetical, system of ranked virtual farms. Results are discussed in light of transboundary water appropriation and demonstrate the approach's suitability for simulating effects of water-rights hierarchies represented by international treaties, interstate stream compacts, intrastate water rights, or ecological requirements. ?? 2007 ASCE.

  3. Correction of algocenosis by the preparation of komplezim in experimental ponds of fish-farm Nyvka

    Directory of Open Access Journals (Sweden)

    L. Dragan

    2016-01-01

    Full Text Available Purpose. To investigate the effect of the bacterial preparation "Komplezim", which is recommended for the prevention of mass reproduction of blue-green algae through algocoenosis correction, water cleaning and sanitary regime restoration, for the biological balance and self-purification of natural and farmed fish ponds of all sizes exposed to artificial or natural pollution. Methodology. The studies were carried out during 30 days in a 0.01 hectare pond with a depth of 1.0–1.5 m. The doses of the bacterial preparation "Komplezim" in the form of a solution were applied over the water surface of the experimental pond. The conventional techniques of hydrochemistry and hydrobiology were used to perform hydroecological studies. Findings. The study results showed that after the exposure of the bacterial preparation "Komplezim", pH level of water and oxidation rates were within the acceptable limits. Permanganate and dichromate oxidation decreased in the same manner in the middle and end of the experiment compared to initial values. Calcium, magnesium, and sulfate levels were lower compared to control values. This effect can be explained by the fact that bacteria from the “Komplezim” composition in aquatic medium started intensive metabolizing the products of organic decomposition enriched in calcium, magnesium and sulfates. The consequence of the application of "Komplezim" was an increase in the concentration of organic chlorides simultaneously with nitrites. The obtained results indicate that bacteria strains included in the “Komplezim” composition inhibit the processes of cyanobacteria reproduction by algocenosis correction and contributes to the optimization of hydrochemical conditions for pond fish rearing. Originality. The effect of the bacterial preparation "Komplezim" on the reproduction of blue-green algae and hydro-chemical composition of the water has been investigated for the first time. Practical value. Application of the

  4. Biochemical characteristics of four marine fish skins in Korea.

    Science.gov (United States)

    Cho, Jae-Kwon; Jin, Young-Guk; Rha, Sung-Ju; Kim, Seon-Jae; Hwang, Jae-Ho

    2014-09-15

    In this study, we investigated the biochemical characteristics of the fish skins of four industrial species: olive flounder (Paralichthys olivaceus), black rockfish (Sebastes schlegeli), sea bass (Lateolabrax maculatus) and red sea bream (Pagrus major). There is high domestic demand in Korea for farming of these fish for human consumption. Crude protein contents in the skin of these fish ranged from 73% to 94% by dry weight; this was in part due to a high content of the structural protein, collagen. Among the four species, olive flounder had the thickest dermal and epidermal layers in the dorsal skin. This species was also associated with the highest extraction ratio of acid-soluble collagen. We also examined whether fish skin could be a cost-effective alternative to current fish meal sources. Our analysis indicates that, when supplemented with additional fish oils and essential amino acids, fish skin is a viable alternative for fish meal formulations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Design of extended length submerged traveling screen and submerged bar screen fish guidance equipment

    International Nuclear Information System (INIS)

    Bardy, D.; Lindstrom, M.; Fechner, D.

    1991-01-01

    The hydropower projects on the Snake and lower Columbia Rivers in the Pacific Northwest are unique because these rivers are also the spawning grounds for migratory salmon. The salmon swim upstream from the ocean, lay their eggs, and die. The newly hatched fingerlings must then make their way past the hydroelectric dams to the ocean. Two separate bypass systems are needed, one to pass the adult fish going upstream, and one to pass the fingerlings going downstream. This paper addresses the design considerations for two of the components of the downstream migrant fish passage facilities, the extended Submerged Traveling Screen and Submerged Bar Screen

  6. The operation and production in Penaeid farm

    Directory of Open Access Journals (Sweden)

    ludi parwadani aji

    2011-06-01

    Full Text Available Penaeid prawn demand in the world market has brought about a dramatic raise in the price of prawns, so, the aquaculture prawn industry also increase. Prawn farming can be divided by intensive, semi intensive or extensive culture system. Extensive culture system has low stocking densities, whereas, intensive culture (very high stocking densities has highest level of environmental control such as recirculation system and stable ecological system. Predation and disease is the major obstacles in culture system. To deal with predation, farmers use net for covering the ponds and fencing the ponds. Disease organism such as parasites, bacteria, fungal and viruses may be eliminated through sterilization of the water. The commercial diets made from squid and white fish meal may replace fresh diet in semi-intensive culture as fish diet has a problem with preservation. Moreover, maintaining water quality such as dissolve oxygen, pH, nitrogen (ammonia and ammonium and temperature is very important to support productivity and profitability in prawn farming. The most prominent aims at harvest are to pack the prawn in a way that avoids physical damage, minimize the quantity of prawn left on the bottom of pond, and directly chill prawn. Therefore, good management of water quality, feeding, disease, predation, and harvesting is important in prawn culture.

  7. A game theory based framework for assessing incentives for local area collaboration with an application to Scottish salmon farming.

    Science.gov (United States)

    Murray, Alexander G

    2014-08-01

    Movements of water that transport pathogens mean that in net-pen aquaculture diseases are often most effectively managed collaboratively among neighbours. Such area management is widely and explicitly applied for pathogen management in marine salmon farms. Effective area management requires the active support of farm managers and a simple game-theory based framework was developed to identify the conditions required under which collaboration is perceived to be in their own best interest. The model applied is based on area management as practiced for Scottish salmon farms, but its simplicity allows it to be generalised to other area-managed net-pen aquaculture systems. In this model managers choose between purchasing tested pathogen-free fish or cheaper, untested fish that might carry pathogens. Perceived pay-off depends on degree of confidence that neighbours will not buy untested fish, risking input of pathogens that spread between farms. For a given level of risk, confidence in neighbours is most important in control of moderate-impact moderate-probability diseases. Common low-impact diseases require high confidence since there is a high probability a neighbour will import, while testing for rare high-impact diseases may be cost-effective regardless of neighbours actions. In some cases testing may be beneficial at an area level, even if all individual farms are better off not testing. Higher confidence is required for areas with many farms and so focusing management on smaller, epidemiologically imperfect, areas may be more effective. The confidence required for collaboration can be enhanced by the development of formal agreements and the involvement of outside disinterested parties such as trade bodies or government. Copyright © 2014. Published by Elsevier B.V.

  8. Phenotypic and genotypic characterization of Flavobacterium psychrophilum from Finnish fish farms

    DEFF Research Database (Denmark)

    Madetoja, J.; Hanninen, M.L.; Hirvela-Koski, V.

    2001-01-01

    Finnish isolates (n = 37) of Flavobacterium psychrophilum isolated from farmed salmonids were studied using phenotypic and genotypic characteristics. The characteristics of isolates were compared with the characteristics of Swedish and Estonian F. psychrophilum isolates and the type strain, F...

  9. Status and Habitat Requirements of White Sturgeon Populations in the Columbia River Downstream from McNary Dam, 1988-1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Nigro, Anthony A. (Oregon Dept. of Fish and Wildlife, Portland, OR (USA))

    1989-09-01

    We report on our progress from April 1988 through March 1989 on determining the status and habitat requirements of white sturgeon populations in the Columbia River downstream from McNary Dam. Highlights of results of our work in the Dalles and Bonneville reservoirs are: using setlines, we caught 1,586 sturgeon in The Dalles Reservoir and 484 sturgeon in Bonneville Reservoir in 1988. Fork length of fish caught ranged from 34 cm to 274 cm. Of the fish caught we marked 1,248 in The Dalles Reservoir and 341 in Bonneville Reservoir. Of the fish marked in 1988, we recaptured 82 in The Dalles Reservoir and none in Bonneville Reservoir. We recaptured 89 fish marked in 1987 in The Dalles Reservoir. Anglers recaptured 35 fish marked in 1988 and 16 fish marked in 1987 in The Dalles Reservoir. Anglers recaptured 2 sturgeon marked in 1988 in Bonneville Reservoir. Individual papers were processed separately for the data base.

  10. Nitrates in drinking water: relation with intensive livestock production.

    Science.gov (United States)

    Giammarino, M; Quatto, P

    2015-01-01

    An excess of nitrates causes environmental pollution in receiving water bodies and health risk for human, if contaminated water is source of drinking water. The directive 91/676/ CEE [1] aims to reduce the nitrogen pressure in Europe from agriculture sources and identifies the livestock population as one of the predominant sources of surplus of nutrients that could be released in water and air. Directive is concerned about cattle, sheep, pigs and poultry and their territorial loads, but it does not deal with fish farms. Fish farms effluents may contain pollutants affecting ecosystem water quality. On the basis of multivariate statistical analysis, this paper aims to establish what types of farming affect the presence of nitrates in drinking water in the province of Cuneo, Piedmont, Italy. In this regard, we have used data from official sources on nitrates in drinking water and data Arvet database, concerning the presence of intensive farming in the considered area. For model selection we have employed automatic variable selection algorithm. We have identified fish farms as a major source of nitrogen released into the environment, while pollution from sheep and poultry has appeared negligible. We would like to emphasize the need to include in the "Nitrate Vulnerable Zones" (as defined in Directive 91/676/CEE [1]), all areas where there are intensive farming of fish with open-system type of water use. Besides, aquaculture open-system should be equipped with adequate downstream system of filtering for removing nitrates in the wastewater.

  11. Fish movement in an Atlantic Forest stream

    Directory of Open Access Journals (Sweden)

    Rosana Mazzoni

    2018-03-01

    Full Text Available ABSTRACT Given the importance of fish movement to the dynamics and maintenance of stream dwelling fish communities from the Atlantic Forest, we analysed patterns of fish movement in a coastal stream from Southeastern Brazil, using mark-recapture technique. Displacement distance of each species were presented and discussed considering seasonal (rainy and dry and body size patterns. We marked 10 species along the stream and recaptured 440 (34.6% of the 1,270 marked fishes. The species with significant number of upstream moving individuals were Astyanax janeiroensis, Characidium interruptum, Astyanax hastatus, Parotocinclus maculicauda and Awaous tajasica. Only Pimelodella lateristriga presented significant differences between resident and moving individuals. Characidium interruptum and A. tajasica demonstrated greater downstream and upstream movement, respectively, moving up to 2,100 m. Even after controlling for species identity we found no significant correlation between fish length and individual displacement distance. Fishes moved longer distances during the rainy season, in accordance to the breeding season. Patterns of fish movement were in agreement to life-history traits of many of the studied species and can be reflecting specific behaviour and morphologies.

  12. Impact of wastewater on fish health: a case study at the Neckar River (Southern Germany) using biomarkers in caged brown trout as assessment tools.

    Science.gov (United States)

    Vincze, Krisztina; Scheil, Volker; Kuch, Bertram; Köhler, Heinz R; Triebskorn, Rita

    2015-08-01

    The present work describes a field survey aiming at assessing the impact of a sewage treatment plant (STP) effluent on fish health by means of biomarkers. Indigenous fish were absent downstream of the STP. To elucidate the reason behind this, brown trout (Salmo trutta f. fario) were exposed in floating steel cages up- and downstream of a STP located at the Neckar River near Tübingen (Southern Germany), for 10 and 30 days. A combination of biomarker methods (histopathological investigations, analysis of the stress protein Hsp70, micronucleus test, B-esterase assays) offered the possibility to investigate endocrine, geno-, proteo- and neurotoxic effects in fish organs. Biological results were complemented with chemical analyses on 20 accumulative substances in fish tissue. Even after short-term exposure, biomarkers revealed clear evidence of water contamination at both Neckar River sites; however, physiological responses of caged brown trout were more severe downstream of the STP. According to this, similar bioaccumulation levels (low μg/kg range) of DDE and 12 polycyclic aromatic hydrocarbons (PAHs) were detected at both sampling sites, while up to fourfold higher concentrations of four PAHs, methyl-triclosan and two synthetic musks occurred in the tissues of downstream-exposed fish. The results obtained in this study suggest a constitutive background pollution at both sites investigated at the Neckar River and provided evidence for the additional negative impact of the STP Tübingen on water quality and the health condition of fish.

  13. Simulation of wake effects between two wind farms

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Réthoré, Pierre-Elouan; Palma, Jose

    2015-01-01

    SCADA data, recorded on the downstream wind farm, has been used to identify flow cases with visible clustering effects. The inflow condition is derived from a partly undisturbed wind turbine, due to lack of mast measurements. The SCADA data analysis concludes that centre of the deficit...... flow models represented in this benchmark include both RANS models, mesoscale models and engineering models. The flow cases, identified according to the wind speed level and inflow sector, have been simulated and validated with the SCADA results. The model validation concludes that all models more...

  14. Spatial structure of kinetic energy spectra in LES simulations of flow in an offshore wind farm

    Science.gov (United States)

    Fruh, Wolf-Gerrit; Creech, Angus

    2017-04-01

    The evolution of wind turbine and wind farm wakes was investigated numerically for the case of Lillgrund wind farm consisting of a tightly packed array of 48 turbines. The simulations for a number of wind directions at a free wind speed of just under the rated wind speed in a neutrally stable atmosphere were carried out using Large-Eddy Simulations with the adaptive Finite-Element CFD solver Fluidity. The results were interpolated from the irregularly spaced mesh nodes onto a regular grid with comparable spatial resolution at horizontal slices at various heights. To investigate the development of the wake as the flow evolves through the array, spectra of the kinetic energy in sections perpendicular to the wind directions within the wake and to the sides of the array were calculated. This paper will present the key features and spectral slopes of the flow as a function of downstream distance from the front turbine through and beyond the array. The main focus will be on the modification of the spectra as the flow crosses a row of turbines followed by its decay in the run-up to the next row, but we will also present to wake decay of the wind farm wake downstream of the array.

  15. Recovery from transportation by road of farmed European eel (Anguilla anguilla)

    NARCIS (Netherlands)

    Boerrigter, J.G.J.; Manuel, R.; Bos, van den R.; Roques, J.A.C.; Spanings, T.; Flik, G.; Vis, van de J.W.

    2015-01-01

    The objective of this study was to assess the effects of transportation of marketable eel (0.15 kg) in the Netherlands with respect to welfare. Eels (Anguilla anguilla) were obtained from a commercial farm and acclimatized for 7 weeks at the laboratory. Fish were transported according to regular

  16. PARTICULARITIES AND MANAGEMENT OF THE DISTRIBUTION CHAIN FOR FISH AND FISHERY PRODUCTS

    Directory of Open Access Journals (Sweden)

    Carmen Georgeta NICOLAE

    2015-10-01

    Full Text Available The total quality principles implementation contributes to the improving in meeting the consumer needs, essential reduction of costs and increasing sales. The total quality is a concept that assures the total satisfaction of clients on the entire distribution chain, including all the actors in this chain. The aquaculture and fisheries are very diverse sectors which use different breeding and fishing technologies and provide a wide variety of specific products. This induces a real complexity of the supply and distribution chain for fish and fishery products, including the links from the production point (fishery or farm to the final consumer. The components of the distribution chain differ with the geographic areas, type of farms, transportation, information on the fishery market and management systems. Implementing the total food quality system for fishery products involves the quality specification in all marketing stages for all products, along the entire distribution chain. The present work was focused on identifying the distribution chain for fish and fishery products with the identification of the specificity of this type of chain form farm to end consumer, which is the first step in the implementation of total quality concept in aquaculture, with all the benefits that come with it.

  17. Optimization of wind farm power production using innovative control strategies

    DEFF Research Database (Denmark)

    Duc, Thomas

    Wind energy has experienced a very significant growth and cost reduction over the past decade, and is now able to compete with conventional power generation sources. New concepts are currently investigated to decrease costs of production of electricity even further. Wind farm coordinated control...... deficit caused by the wake downstream, or yawing the turbine to deflect the wake away from the downwind turbine. Simulation results found in the literature indicate that an increase in overall power production can be obtained. However they underline the high sensitivity of these gains to incoming wind...... aligned wind turbines. The experimental results show that the scenarios implemented during the first measurement campaign did not achieve an increase in overall power production, which confirms the difficulty to realize wind farm power optimization in real operating conditions. In the curtailment field...

  18. Concurrent jellyfish blooms and tenacibaculosis outbreaks in Northern Norwegian Atlantic salmon (Salmo salar farms.

    Directory of Open Access Journals (Sweden)

    Sverre Bang Småge

    Full Text Available Tenacibaculosis is an increasing problem in the Norwegian Atlantic salmon aquaculture industry causing significant economic losses. In September 2015, two separate outbreaks of suspected tenacibaculosis occurred at two Atlantic salmon farms in Finnmark County in Northern Norway. The events resulted in major losses of smolts newly transferred into seawater. Prior to, and during the outbreaks, large numbers of small jellyfish, identified as Dipleurosoma typicum (Boeck were observed in the vicinity of the farms and inside the net-pens. This study investigates the possible link between the jellyfish, Tenacibaculum spp. and the tenacibaculosis outbreaks. Bacteriology, histology, scanning and transmission electron microscopy, and real-time RT-PCR screening were performed on both fish and jellyfish samples. Based on the findings, Tenacibaculum finnmarkense was found to be the dominant bacteria associated with the tenacibaculosis outbreaks at both sites and that D. typicum is unlikely to be a vector for this fish pathogenic bacterium. However, results do show that the jellyfish caused direct damage to the fish's skin and may have exacerbated the bacterial infection by allowing an entry point for bacteria.

  19. A case study: Fish production in the integrated farming system of the Black Thai in Yen Chau district (Son La province) in mountainous North-western Vietnam - current state and potential

    OpenAIRE

    Steinbronn, Silke

    2009-01-01

    Son La province is located in mountainous north-western Vietnam and belongs to the poorest regions of the country. In the valleys of this province, fish farming is one of the major activities among farmers who belong to the ethnic Black Thai minority. Up until now, the aquaculture system practiced here has not been scientifically investigated. There is generally very little data available regarding the aquaculture of resource-poor farmers in Southeast Asia. This lack of information can be par...

  20. Climate Change and Fish Availability

    Science.gov (United States)

    Teng, Paul P. S.; Lassa, Jonatan; Caballero-Anthony, Mely

    Human consumption of fish has been trending upwards in the past decades and this is projected to continue. The main sources of fish are from wild fisheries (marine and freshwater) and aquaculture. Climate change is anticipated to affect the availability of fish through its effect on these two sources as well as on supply chain processes such as storage, transport, processing and retail. Climate change is known to result in warmer and more acid oceans. Ocean acidification due to higher CO2 concentration levels at sea modifies the distribution of phytoplankton and zooplankton to affect wild, capture fisheries. Higher temperature causes warm-water coral reefs to respond with species replacement and bleaching, leading to coral cover loss and habitat loss. Global changes in climatic systems may also cause fish invasion, extinction and turnover. While this may be catastrophic for small scale fish farming in poor tropical communities, there are also potential effects on animal protein supply shifts at local and global scales with food security consequences. This paper discusses the potential impacts of climate change on fisheries and aquaculture in the Asian Pacific region, with special emphasis on Southeast Asia. The key question to be addressed is “What are the impacts of global climate change on global fish harvests and what does it mean to the availability of fish?”

  1. Base line studies North Sea wind farms: Final report pelagic fish

    NARCIS (Netherlands)

    Grift, R.E.; Tulp, I.Y.M.; Ybema, M.S.; Couperus, A.S.

    2004-01-01

    The Dutch government has decided to allow the construction of a Near Shore Wind Farm (NSW) demonstration project under the condition that a monitoring programme on - among other things - the ecological impacts is carried out. The Dutch government is responsible for providing a thorough description

  2. Fish innate immunity against intestinal helminths.

    Science.gov (United States)

    Dezfuli, B S; Bosi, G; DePasquale, J A; Manera, M; Giari, L

    2016-03-01

    Most individual fish in farmed and wild populations are infected with parasites. Upon dissection of fish, helminths from gut are often easily visible. Enteric helminths include several species of digeneans, cestodes, acanthocephalans and nematodes. Some insights into biology, morphology and histopathological effects of the main fish enteric helminths taxa will be described here. The immune system of fish, as that of other vertebrates, can be subdivided into specific and aspecific types, which in vivo act in concert with each other and indeed are interdependent in many ways. Beyond the small number of well-described models that exist, research focusing on innate immunity in fish against parasitic infections is lacking. Enteric helminths frequently cause inflammation of the digestive tract, resulting in a series of chemical and morphological changes in the affected tissues and inducing leukocyte migration to the site of infection. This review provides an overview on the aspecific defence mechanisms of fish intestine against helminths. Emphasis will be placed on the immune cellular response involving mast cells, neutrophils, macrophages, rodlet cells and mucous cells against enteric helminths. Given the relative importance of innate immunity in fish, and the magnitude of economic loss in aquaculture as a consequence of disease, this area deserves considerable attention and support. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Fishers' knowledge identifies environmental changes and fish abundance trends in impounded tropical rivers.

    Science.gov (United States)

    Hallwass, Gustavo; Lopes, Priscila F; Juras, Anastácio A; Silvano, Renato A M

    2013-03-01

    The long-term impacts of large hydroelectric dams on small-scale fisheries in tropical rivers are poorly known. A promising way to investigate such impacts is to compare and integrate the local ecological knowledge (LEK) of resource users with biological data for the same region. We analyzed the accuracy of fishers' LEK to investigate fisheries dynamics and environmental changes in the Lower Tocantins River (Brazilian Amazon) downstream from a large dam. We estimated fishers' LEK through interviews with 300 fishers in nine villages and collected data on 601 fish landings in five of these villages, 22 years after the dam's establishment (2006-2008). We compared these two databases with each other and with data on fish landings from before the dam's establishment (1981) gathered from the literature. The data obtained based on the fishers' LEK (interviews) and from fisheries agreed regarding the primary fish species caught, the most commonly used type of fishing gear (gill nets) and even the most often used gill net mesh sizes but disagreed regarding seasonal fish abundance. According to the interviewed fishers, the primary environmental changes that occurred after the impoundment were an overall decrease in fish abundance, an increase in the abundance of some fish species and, possibly, the local extinction of a commercial fish species (Semaprochilodus brama). These changes were corroborated by comparing fish landings sampled before and 22 years after the impoundment, which indicated changes in the composition of fish landings and a decrease in the total annual fish production. Our results reinforce the hypothesis that large dams may adversely affect small-scale fisheries downstream and establish a feasible approach for applying fishers' LEK to fisheries management, especially in regions with a low research capacity.

  4. The thermal regime and species composition of fish and invertebrates in Kelly Warm Spring, Grand Teton National Park, Wyoming

    Science.gov (United States)

    Harper, David; Farag, Aida

    2017-01-01

    We evaluated the thermal regime and relative abundance of native and nonnative fish and invertebrates within Kelly Warm Spring and Savage Ditch, Grand Teton National Park, Wyoming. Water temperatures within the system remained relatively warm year-round with mean temperatures >20 °C near the spring source and >5 °C approximately 2 km downstream of the source. A total of 7 nonnative species were collected: Convict/Zebra Cichlid (Cichlasoma nigrofasciatum), Green Swordtail (Xiphophorus hellerii), Tadpole Madtom (Noturus gyrinus), Guppy (Poecilia reticulata), Goldfish (Carassius auratus), red-rimmed melania snail (Melanoides tuberculata), and American bullfrog tadpoles (Lithobates catesbeianus). Nonnative fish (Zebra Cichlids and Green Swordtails), red-rimmed melania snails, and bullfrog tadpoles dominated the upper 2 km of the system. Abundance estimates of the Zebra Cichlid exceeded 12,000 fish/km immediately downstream of the spring source. Relative abundance of native species increased movingdownstream as water temperatures attenuated with distance from the thermally warmed spring source; however, nonnative species were captured 4 km downstream from the spring. Fish diseases were prevalent in both native and nonnative fish from the Kelly Warm Spring pond. Clinostomum marginatum, a trematode parasite, was found in native species samples, and the tapeworm Diphyllobothrium dendriticum was present in samples from nonnative species. Diphyllobothrium dendriticum is rare in Wyoming. Salmonella spp. were also found in some samples of nonnative species. These bacteria are associated with aquarium fish and aquaculture and are generally not found in the wild.

  5. Effects of outcropping groundwater from the F- and H-Area seepage basins on the distribution of fish in Four Mile Creek

    International Nuclear Information System (INIS)

    Paller, M.H.; Storey, C.

    1990-10-01

    Four Mile Creek was electrofished during June 26--July 2, 1990 to assess the impacts of outcropping ground water form the F- and H-Area Seepage Basins on fish abundance and distribution. Number of fish species and total catch were comparable at sample stations upstream from and downstream from the outcropping zone in Four Mile Creek. Species number and composition downstream from the outcropping zone in Four Mile Creek were similar to species number and composition in unimpacted portions of Pen Branch, Steel Creek, and Meyers Branch. These findings indicate that seepage basin outcropping was not adversely affecting the Four Mile Creek fish community. 5 refs., 3 figs., 4 tabs

  6. Occurrence, bioaccumulation and potential sources of polybrominated diphenyl ethers in typical freshwater cultured fish ponds of South China

    International Nuclear Information System (INIS)

    Zhang Baozhong; Ni Honggang; Guan Yufeng; Zeng, Eddy Y.

    2010-01-01

    To determine the potential input sources of polybrominated diphenyl ethers (PBDEs) to fish farming environments in South China, samples of seven various environmental matrices were collected from October 2006-September 2007. Tri- to deca-BDEs were detected in all samples analyzed, with mean concentrations (±standard deviations) at 5.7 ± 3.6 ng/L in pond water, 15 ± 11 ng/g dry wt. in pond sediment, 12 ± 3.8 ng/g dry wt. in bank soil, 21 ± 20 ng/g lipid wt. in fish, and 93 ± 62 ng/g lipid wt. in fish feeds. In addition, BDE-209 was the major constituent in all samples except fish and BDE-47 was predominant in fish samples. Relatively high abundances of BDE-49 were detected in all the samples compared to those in the penta-BDE technical products. Several bioaccumulation factors were evaluated. Finally, statistical analyses suggested that fish feed, as well as pond water at a lesser degree, may have been the major source of PBDEs in freshwater farmed fish. - Occurrence and sources of polybrominated diphenyl ethers in typical freshwater cultured fish ponds of the Pearl River Delta, South China are examined.

  7. Schooling increases risk exposure for fish navigating past artificial barriers.

    Directory of Open Access Journals (Sweden)

    Bertrand H Lemasson

    Full Text Available Artificial barriers have become ubiquitous features in freshwater ecosystems and they can significantly impact a region's biodiversity. Assessing the risk faced by fish forced to navigate their way around artificial barriers is largely based on assays of individual swimming behavior. However, social interactions can significantly influence fish movement patterns and alter their risk exposure. Using an experimental flume, we assessed the effects of social interactions on the amount of time required for juvenile palmetto bass (Morone chrysops × M. saxatilis to navigate downstream past an artificial barrier. Fish were released either individually or in groups into the flume using flow conditions that approached the limit of their expected swimming stamina. We compared fish swimming behaviors under solitary and schooling conditions and measured risk as the time individuals spent exposed to the barrier. Solitary fish generally turned with the current and moved quickly downstream past the barrier, while fish in groups swam against the current and displayed a 23-fold increase in exposure time. Solitary individuals also showed greater signs of skittish behavior than those released in groups, which was reflected by larger changes in their accelerations and turning profiles. While groups displayed fission-fusion dynamics, inter-individual positions were highly structured and remained steady over time. These spatial patterns align with theoretical positions necessary to reduce swimming exertion through either wake capturing or velocity sheltering, but diverge from any potential gains from channeling effects between adjacent neighbors. We conclude that isolated performance trials and projections based on individual behaviors can lead to erroneous predictions of risk exposure along engineered structures. Our results also suggest that risk perception and behavior may be more important than a fish's swimming stamina in artificially modified systems.

  8. Schooling increases risk exposure for fish navigating past artificial barriers.

    Science.gov (United States)

    Lemasson, Bertrand H; Haefner, James W; Bowen, Mark D

    2014-01-01

    Artificial barriers have become ubiquitous features in freshwater ecosystems and they can significantly impact a region's biodiversity. Assessing the risk faced by fish forced to navigate their way around artificial barriers is largely based on assays of individual swimming behavior. However, social interactions can significantly influence fish movement patterns and alter their risk exposure. Using an experimental flume, we assessed the effects of social interactions on the amount of time required for juvenile palmetto bass (Morone chrysops × M. saxatilis) to navigate downstream past an artificial barrier. Fish were released either individually or in groups into the flume using flow conditions that approached the limit of their expected swimming stamina. We compared fish swimming behaviors under solitary and schooling conditions and measured risk as the time individuals spent exposed to the barrier. Solitary fish generally turned with the current and moved quickly downstream past the barrier, while fish in groups swam against the current and displayed a 23-fold increase in exposure time. Solitary individuals also showed greater signs of skittish behavior than those released in groups, which was reflected by larger changes in their accelerations and turning profiles. While groups displayed fission-fusion dynamics, inter-individual positions were highly structured and remained steady over time. These spatial patterns align with theoretical positions necessary to reduce swimming exertion through either wake capturing or velocity sheltering, but diverge from any potential gains from channeling effects between adjacent neighbors. We conclude that isolated performance trials and projections based on individual behaviors can lead to erroneous predictions of risk exposure along engineered structures. Our results also suggest that risk perception and behavior may be more important than a fish's swimming stamina in artificially modified systems.

  9. Meeting the food and nutrition needs of the poor: the role of fish and the opportunities and challenges emerging from the rise of aquaculture.

    Science.gov (United States)

    Beveridge, M C M; Thilsted, S H; Phillips, M J; Metian, M; Troell, M; Hall, S J

    2013-10-01

    People who are food and nutrition insecure largely reside in Asia and Sub-Saharan Africa and for many, fish represents a rich source of protein, micronutrients and essential fatty acids. The contribution of fish to household food and nutrition security depends upon availability, access and cultural and personal preferences. Access is largely determined by location, seasonality and price but at the individual level it also depends upon a person's physiological and health status and how fish is prepared, cooked and shared among household members. The sustained and rapid expansion of aquaculture over the past 30 years has resulted in >40% of all fish now consumed being derived from farming. While aquaculture produce increasingly features in the diets of many Asians, it is much less apparent among those living in Sub-Saharan Africa. Here, per capita fish consumption has grown little and despite the apparently strong markets and adequate biophysical conditions, aquaculture has yet to develop. The contribution of aquaculture to food and nutrition security is not only just an issue of where aquaculture occurs but also of what is being produced and how and whether the produce is as accessible as that from capture fisheries. The range of fish species produced by an increasingly globalized aquaculture industry differs from that derived from capture fisheries. Farmed fishes are also different in terms of their nutrient content, a result of the species being grown and of rearing methods. Farmed fish price affects access by poor consumers while the size at which fish is harvested influences both access and use. This paper explores these issues with particular reference to Asia and Africa and the technical and policy innovations needed to ensure that fish farming is able to fulfil its potential to meet the global population's food and nutrition needs. © 2013 World Fish. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the

  10. Water intake fish diversion apparatus

    International Nuclear Information System (INIS)

    Taft, E.P. III; Cook, T.C.

    1995-01-01

    A fish diversion apparatus uses a plane screen to divert fish for variety of types of water intakes in order to protect fish from injury and death. The apparatus permits selection of a relatively small screen angle, for example ten degrees, to minimize fish injury. The apparatus permits selection of a high water velocity, for example ten feet per second, to maximize power generation efficiency. The apparatus is especially suitable retrofit to existing water intakes. The apparatus is modular to allow use plural modules in parallel to adjust for water flow conditions. The apparatus has a floor, two opposite side walls, and a roof which define a water flow passage and a plane screen within the passage. The screen is oriented to divert fish into a fish bypass which carries fish to a safe discharge location. The dimensions of the floor, walls, and roof are selected to define the dimensions of the passage and to permit selection of the screen angle. The floor is bi-level with a level upstream of the screen and a level beneath screen selected to provide a uniform flow distribution through the screen. The apparatus may include separation walls to provide a water flow channel between the apparatus and the water intake. Lead walls may be used to adjust water flow conditions into the apparatus. The apparatus features stoplog guides near its upstream and downstream ends to permit the water flow passage to be dewatered. 3 figs

  11. Control strategies for wind farm power optimization: LES study

    Science.gov (United States)

    Ciri, Umberto; Rotea, Mario; Leonardi, Stefano

    2017-11-01

    Turbines in wind farms operate in off-design conditions as wake interactions occur for particular wind directions. Advanced wind farm control strategies aim at coordinating and adjusting turbine operations to mitigate power losses in such conditions. Coordination is achieved by controlling on upstream turbines either the wake intensity, through the blade pitch angle or the generator torque, or the wake direction, through yaw misalignment. Downstream turbines can be adapted to work in waked conditions and limit power losses, using the blade pitch angle or the generator torque. As wind conditions in wind farm operations may change significantly, it is difficult to determine and parameterize the variations of the coordinated optimal settings. An alternative is model-free control and optimization of wind farms, which does not require any parameterization and can track the optimal settings as conditions vary. In this work, we employ a model-free optimization algorithm, extremum-seeking control, to find the optimal set-points of generator torque, blade pitch and yaw angle for a three-turbine configuration. Large-Eddy Simulations are used to provide a virtual environment to evaluate the performance of the control strategies under realistic, unsteady incoming wind. This work was supported by the National Science Foundation, Grants No. 1243482 (the WINDINSPIRE project) and IIP 1362033 (I/UCRC WindSTAR). TACC is acknowledged for providing computational time.

  12. Development of harvesting and up concentration technologies for microalgae as an ingredient in fish feed

    DEFF Research Database (Denmark)

    Safafar, Hamed; Jacobsen, Charlotte; Møller, Per

    2014-01-01

    andfish oil. In applications of algae in fish feed, it is essential to produce a product comparable to fish proteinand fish oil both in terms of quality and costs.Downstream processing of microalgae includes harvest, dewatering, cell rupture, fractionation and drying.The dewatering and drying which...... ingredients forfish feed. Further we evaluate the chemical composition of six different microalgae species including;Nanochloropsis limnethica, Chlorella sorokiniana, Phaeodactylum tinctorium, Dunaliella salina,Nannochloropsis salina and Nannochloropsis occulata ....

  13. Wind tunnel study of the power output spectrum in a micro wind farm

    International Nuclear Information System (INIS)

    Bossuyt, Juliaan; Meyers, Johan; Howland, Michael F.; Meneveau, Charles

    2016-01-01

    Instrumented small-scale porous disk models are used to study the spectrum of a surrogate for the power output in a micro wind farm with 100 models of wind turbines. The power spectra of individual porous disk models in the first row of the wind farm show the expected -5/3 power law at higher frequencies. Downstream models measure an increased variance due to wake effects. Conversely, the power spectrum of the sum of the power over the entire wind farm shows a peak at the turbine-to-turbine travel frequency between the model turbines, and a near -5/3 power law region at a much wider range of lower frequencies, confirming previous LES results. Comparison with the spectrum that would result when assuming that the signals are uncorrelated, highlights the strong effects of correlations and anti-correlations in the fluctuations at various frequencies. (paper)

  14. The cotton farming pipeline of Malawi and South Africa: Management implications

    Directory of Open Access Journals (Sweden)

    J. P. Grundling

    2008-12-01

    Full Text Available Purpose of the study: The purpose this paper is to identify and describe the characteristics and influences of the cotton farming pipeline in Malawi and South Africa. Problem investigated: A broad based approach was followed to investigate the cotton farming pipeline to identify the major driving forces of the cotton pipeline in each of the respective countries. Research approach: A qualitative field research approach was followed to compile data on cotton farming in Malawi and South Africa. Data was compiled upstream from input suppliers, downstream from ginners, cotton transport conveyors, cotton marketing managers and agricultural government officials as well as from farmers and agricultural organizations. Findings: In Malawi a family farming model is followed versus an industrial model of production in South Africa. Despite the differences in approach, the farmers in both countries are faced with similar problems. In this regard, an urgent rethinking of the technological conditions of production and the possibilities of technological change is needed. Recommendations: The research proposes that these countries can benefit from establishing institutions like agricultural co-operatives and mechanisms like the development of a free traffic mechanism of seed-cotton. Conclusion: The present research may assist in developing first layer managerial recommendations that could enhance the sustainability and co-existence of cotton farming in the two countries.

  15. Perceived importance of sustainability and ethics related to fish: a consumer behavior perspective.

    Science.gov (United States)

    Verbeke, Wim; Vanhonacker, Filiep; Sioen, Isabelle; Van Camp, John; De Henauw, Stefaan

    2007-11-01

    Although sustainability and ethics are of increasing public importance, little research has been conducted to reveal its association with fish consumer behavior. Cross-sectional data were collected through a postal self-administered survey (June 2005) from a sample of 381 Flemish women aged 20-50 years. Consumers attach high perceived importance to sustainability and ethics related to fish. However, this perceived importance is neither correlated with fish consumption frequency nor with general attitude toward eating fish. Refusing to eat wild fish is grounded in sustainability and ethical concerns, whereas the decision not to eat farmed fish is associated with a lower expected intrinsic quality rather than shaped by importance attached to sustainability and ethical issues.

  16. Genetic characterisation of farmed rainbow trout in Norway: intra- and inter-strain variation reveals potential for identification of escapees

    Directory of Open Access Journals (Sweden)

    Glover Kevin A

    2008-12-01

    Full Text Available Abstract Background The rainbow trout (Oncorhynchus mykiss is one of the most important aquaculture species in the world, and Norway is one of the largest producers. The present study was initiated in response to a request from the Norwegian police authority to identify the farm of origin for 35 escaped rainbow trout captured in a fjord. Eleven samples, each consisting of approximately 47 fish, were collected from the three farms operating in the fjord where the escapees were captured. In order to gain a better general understanding of the genetic structure of rainbow trout strains used in Norwegian aquaculture, seven samples (47 fish per sample were collected from six farms located outside the region where the escapees were captured. All samples, including the escapees, were genotyped with 12 microsatellite loci. Results All samples displayed considerable genetic variability at all loci (mean number of alleles per locus per sample ranged from 5.4–8.6. Variable degrees of genetic differentiation were observed among the samples, with pair-wise FST values ranging from 0–0.127. Self-assignment tests conducted among the samples collected from farms outside the fjord where the escapees were observed gave an overall correct assignment of 82.5%, demonstrating potential for genetic identification of escapees. In the "real life" assignment of the 35 captured escapees, all were excluded from two of the samples included as controls in the analysis, and 26 were excluded from the third control sample. In contrast, only 1 of the escapees was excluded from the 11 pooled samples collected on the 3 farms operating in the fjord. Conclusion Considerable genetic variation exists within and among rainbow trout strains farmed in Norway. Together with modern statistical methods, this will provide commercial operators with a tool to monitor breeding and fish movements, and management authorities with the ability to identify the source of escapees. The data

  17. Radioecology of the Rhone basin: data on the fish of the Rhone (1974-1984)

    International Nuclear Information System (INIS)

    Lambrechts, A.; Foulquier, L.

    1987-01-01

    Some twenty nuclear sites are located along the Rhone. A radioecological study of the river has been in progress since 1974 and a brief outline is given of its hydrological, chemical, sedimentological and biological features. The techniques used for sampling, processing and radioactivity measurement in fish are also described. A summary of the results demonstrates the influence of the nuclear power stations and fuel cycle plants on the evolution of radioactivity levels in fish as a function of time or distance from liquid waste discharge points. Comparison with data for the Meuse shows that activities in fish downstream of the nuclear power stations are comparable in both rivers. Levels are, however, higher in the Rhone downstream from the Marcoule reprocessing plant. The data collected in situ together with the results of laboratory experiments demonstrate the mechanisms of transfer of radionuclides into the aquatic environment and supply information for the protection of environmental health. (author)

  18. Sustainability evaluation of different systems for sea cucumber ( Apostichopus japonicus) farming based on emergy theory

    Science.gov (United States)

    Wang, Guodong; Dong, Shuanglin; Tian, Xiangli; Gao, Qinfeng; Wang, Fang

    2015-06-01

    Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is affected by the diversity of economic level, meteorological and hydrological parameters in different regions. The present study evaluated the economic benefits, environmental impact, and sustainability of indoor, semi-intensive and extensive farming systems of sea cucumber ( Apostichopus japonicus) in the same region. The results showed that A. japonicus indoor farming system was high in input and output (yield) whereas pond extensive farming system was low in input and output. The output/input ratio of indoor farming system was lower than that of pond extensive farming system, and the output/input ratio of semi-intensive farming system fell in between them. The environmental loading ratio of A. japonicus extensive farming system was lower than that of indoor farming system. In addition, the emergy yield and emergy exchange ratios, and emergy sustainability and emergy indexes for sustainable development were higher in extensive farming system than those in indoor farming system. These results indicated that the current extensive farming system exerted fewer negative influences on the environment, made more efficient use of available resources, and met more sustainable development requirements than the indoor farming system. A. japonicus farming systems showed more emergy benefits than fish farming systems. The pond farming systems of A. japonicus exploited more free local environmental resources for production, caused less potential pressure on the local environment, and achieved higher sustainability than indoor farming system.

  19. Relation of contaminants to fish intersex in riverine sport fishes.

    Science.gov (United States)

    Grieshaber, Casey A; Penland, Tiffany N; Kwak, Thomas J; Cope, W Gregory; Heise, Ryan J; Law, J Mac; Shea, Damian; Aday, D Derek; Rice, James A; Kullman, Seth W

    2018-06-20

    Endocrine active compounds (EACs) are pollutants that have been recognized as an emerging and widespread threat to aquatic ecosystems globally. Intersex, the presence of female germ cells within a predominantly male gonad, is considered a biomarker of endocrine disruption caused by EACs. We measured a suite of EACs and assessed their associated impacts on fish intersex occurrence and severity in a large, regulated river system in North Carolina and South Carolina, USA. Our specific objective was to determine the relationship of contaminants in water, sediment, and fish tissue with the occurrence and severity of the intersex condition in wild, adult black bass (Micropterus), sunfish (Lepomis), and catfish (Ictaluridae) species at 11 sites located on the Yadkin-Pee Dee River. Polycyclic aromatic hydrocarbons (PAHs), ethinylestradiol (EE2), and heavy metals were the most prevalent contaminants that exceeded effect levels for the protection of aquatic organisms. Fish intersex condition was most frequently observed and most severe in black basses and was less frequently detected and less severe in sunfishes and catfishes. The occurrence of the intersex condition in fish showed site-related effects, rather than increasing longitudinal trends from upstream to downstream. Mean black bass and catfish tissue contaminant concentrations were higher than that of sunfish, likely because of the latter's lower trophic position in the food web. Principal component analysis identified waterborne PAHs as the most correlated environmental contaminant with intersex occurrence and severity in black bass and sunfish. As indicated by the intersex condition, EACs have adverse but often variable effects on the health of wild sport fishes in this river, likely due to fluctuations in EAC inputs and the dynamic nature of the riverine system. These findings enhance the understanding of the relationship between contaminants and fish health and provide information to guide ecologically

  20. Fish Pond Aquaculture in Cameroon: A Field Survey of Determinants for Farmers' Adoption Behaviour

    Science.gov (United States)

    Ndah, Hycenth Tim; Knierim, Andrea; Ndambi, Oghaiki Asaah

    2011-01-01

    Although fish farming in Cameroon started in the late 1940s, currently the country meets only half of its domestic demand for fish. This article examines the complex issue of farmers' adoption decisions and attempts to answer why there is a lag in the diffusion process. The theory of behaviour modification and key variables of adoption form the…

  1. Comparative CFD study of the effect of the presence of downstream turbines on upstream ones using a rotational speed control system

    International Nuclear Information System (INIS)

    Breton, S-P; Nilsson, K; Ivanell, S; Olivares-Espinosa, H; Masson, C; Dufresne, L

    2014-01-01

    The effect of a downstream turbine on the production of a turbine located upstream of the latter is studied in this work. This is done through the use of two CFD simulation codes, namely OpenFOAM and EllipSys3D, which solve the Navier-Stokes equations in their incompressible form using a finite volume approach. In both EllipSys3D and OpenFoam, the LES (Large Eddy Simulation) technique is used for modelling turbulence. The wind turbine rotors are modelled as actuator disks whose loading is determined through the use of tabulated airfoil data by applying the blade-element method. A generator torque controller is used in both simulation methods to ensure that the simulated turbines adapt, in terms of rotational velocity, to the inflow conditions they are submited to. Results from both simulation codes, although they differ slightly, show that the downstream turbine affects the upstream one when the spacing between the turbines is small. This is also suggested to be the case looking at measurements performed at the Lillgrund offshore wind farm, whose turbines are located unusually close to each other. However, for distances used in today's typical wind farms, this effect is shown by our calculations not to be significant

  2. Stewardship and risk: An empirically grounded theory of organic fish farming in Scotland

    NARCIS (Netherlands)

    Georgakopoulos, G.; Ciancanelli, P.; Coulson, A.; Kaldis, P.E.

    2008-01-01

    It has long been assumed ownership gives farmers incentives to act as stewards of the land. On this basis, quasi-property rights are granted to fish farmers to encourage them to manage risks to the aquatic environment. This paper offers an empirically grounded theorisation of fish farmers’

  3. Science.gov (United States)

    QUATTO, P.

    2015-01-01

    Summary Introduction. An excess of nitrates causes environmental pollution in receiving water bodies and health risk for human, if contaminated water is source of drinking water. The directive 91/676/ CEE [1] aims to reduce the nitrogen pressure in Europe from agriculture sources and identifies the livestock population as one of the predominant sources of surplus of nutrients that could be released in water and air. Directive is concerned about cattle, sheep, pigs and poultry and their territorial loads, but it does not deal with fish farms. Fish farms effluents may contain pollutants affecting ecosystem water quality. Methods. On the basis of multivariate statistical analysis, this paper aims to establish what types of farming affect the presence of nitrates in drinking water in the province of Cuneo, Piedmont, Italy. In this regard, we have used data from official sources on nitrates in drinking water and data Arvet database, concerning the presence of intensive farming in the considered area. For model selection we have employed automatic variable selection algorithm. Results and discussion. We have identified fish farms as a major source of nitrogen released into the environment, while pollution from sheep and poultry has appeared negligible. We would like to emphasize the need to include in the "Nitrate Vulnerable Zones" (as defined in Directive 91/676/CEE [1]), all areas where there are intensive farming of fish with open-system type of water use. Besides, aquaculture open-system should be equipped with adequate downstream system of filtering for removing nitrates in the wastewater. PMID:26900335

  4. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Chinook Salmon.

    Science.gov (United States)

    1986-04-01

    fin is moderately forked; America are distributed from the adipose is stout and prominent; a Sacramento-San Joaquin River system free- tipoed flesh...downstream. Joaquin Rivers to spawn in 1953-83 The completed nest forms an oval de - (data from Taylor 1974; Reavis 1983; pression with a mound of gravel...warmwater fish produc- of engineering requirements and bio- tion and costs . Calif. Dep. Fish logical criteria. U.S. Army Corps Game, Inland Fish

  5. Reproductive health indicators of fishes from Pennsylvania watersheds: association with chemicals of emerging concern.

    Science.gov (United States)

    Blazer, V S; Iwanowicz, D D; Walsh, H L; Sperry, A J; Iwanowicz, L R; Alvarez, D A; Brightbill, R A; Smith, G; Foreman, W T; Manning, R

    2014-10-01

    Fishes were collected at 16 sites within the three major river drainages (Delaware, Susquehanna, and Ohio) of Pennsylvania. Three species were evaluated for biomarkers of estrogenic/antiandrogenic exposure, including plasma vitellogenin and testicular oocytes in male fishes. Smallmouth bass Micropterus dolomieu, white sucker Catostomus commersonii, and redhorse sucker Moxostoma species were collected in the summer, a period of low flow and low reproductive activity. Smallmouth bass were the only species in which testicular oocytes were observed; however, measurable concentrations of plasma vitellogenin were found in male bass and white sucker. The percentage of male bass with testicular oocytes ranged from 10 to 100%, with the highest prevalence and severity in bass collected in the Susquehanna drainage. The percentage of males with plasma vitellogenin ranged from 0 to 100% in both bass and sucker. Biological findings were compared with chemical analyses of discrete water samples collected at the time of fish collections. Estrone concentrations correlated with testicular oocytes prevalence and severity and with the percentage of male bass with vitellogenin. No correlations were noted with the percentage of male sucker with vitellogenin and water chemical concentrations. The prevalence and severity of testicular oocytes in bass also correlated with the percent of agricultural land use in the watershed above a site. Two sites within the Susquehanna drainage and one in the Delaware were immediately downstream of wastewater treatment plants to compare results with upstream fish. The percentage of male bass with testicular oocytes was not consistently higher downstream; however, severity did tend to increase downstream.

  6. Tracing Asian Seabass Individuals to Single Fish Farms Using Microsatellites

    Science.gov (United States)

    Yue, Gen Hua; Xia, Jun Hong; Liu, Peng; Liu, Feng; Sun, Fei; Lin, Grace

    2012-01-01

    Traceability through physical labels is well established, but it is not highly reliable as physical labels can be easily changed or lost. Application of DNA markers to the traceability of food plays an increasingly important role for consumer protection and confidence building. In this study, we tested the efficiency of 16 polymorphic microsatellites and their combinations for tracing 368 fish to four populations where they originated. Using the maximum likelihood and Bayesian methods, three most efficient microsatellites were required to assign over 95% of fish to the correct populations. Selection of markers based on the assignment score estimated with the software WHICHLOCI was most effective in choosing markers for individual assignment, followed by the selection based on the allele number of individual markers. By combining rapid DNA extraction, and high-throughput genotyping of selected microsatellites, it is possible to conduct routine genetic traceability with high accuracy in Asian seabass. PMID:23285169

  7. China’s new-age small farms and their vertical integration: agribusiness or co-ops?

    Science.gov (United States)

    Huang, Philip C C

    2011-01-01

    The future of Chinese agriculture lies not with large mechanized farms but with small capital-labor dual intensifying family farms for livestock-poultry-fish raising and vegetable-fruit cultivation. Chinese food consumption patterns have been changing from the old 8:1:1 pattern of 8 parts grain, 1 part meat, and 1 part vegetables to a 4:3:3 pattern, with a corresponding transformation in agricultural structure. Small family-farming is better suited for the new-age agriculture, including organic farming, than large-scale mechanized farming, because of the intensive, incremental, and variegated hand labor involved, not readily open to economies of scale, though compatible with economies of scope. It is also better suited to the realities of severe population pressure on land. But it requires vertical integration from cultivation to processing to marketing, albeit without horizontal integration for farming. It is against such a background that co-ops have arisen spontaneously for integrating small farms with processing and marketing. The Chinese government, however, has been supporting aggressively capitalistic agribusinesses as the preferred mode of vertical integration. At present, Chinese agriculture is poised at a crossroads, with the future organizational mode for vertical integration as yet uncertain.

  8. The Effects of Dams on Downstream Channel Characteristics in Pennsylvania and Maryland: Assessing the Potential Consequences of Dam Removal

    Science.gov (United States)

    Skalak, K. J.; Pizzuto, J. E.; Jenkins, P.

    2003-12-01

    The potential downstream effects of dam removal were assessed on fifteen sites of varying dam size and characteristics in Pennsylvania and Maryland. The dams ranged in size from a 30 cm high fish weir to a water supply dam 57 m high. Stream order ranged from 1 to 4. The dams are located in watersheds with varying degrees of human disturbance and urbanization. The dams are also operated differently, with significant consequences for hydraulic residence time and downstream flow variability. Most streams were alluvial, but 6 of the reaches were clearly bedrock channels. We hypothesize that the channel upstream, which is unaffected by the dam, will provide an accurate model for the channel downstream of the dam long after dam removal. Therefore, reaches upstream and downstream of the dam were compared to determine the effects of the dam as well as the condition of the stream that will ultimately develop decades after dam removal. Surprisingly, the dams had no consistent influence on channel morphology. However, the percentage of sand is significantly lower downstream than upstream: the mean % sand downstream is 11.47%, while the mean % sand upstream is 21.39%. The coarser fractions of the bed, as represented by the 84th percentile grain diameter, are unaffected by the presence of the dam. These results imply that decades after dam removal, the percentage of sand on the bed will increase, but the coarse fraction of the bed will remain relatively unchanged.

  9. Characterization of the Cultivable Gut Microflora in Wild-Caught 
Mediterranean Fish Species.

    Science.gov (United States)

    Jammal, Ahmad; Bariche, Michel; Zu Dohna, Heinrich; Kambris, Zakaria

    2017-05-01

    Microflora of the gastrointestinal tract plays important roles in food digestion, nutrient absorption and in host defense against ingested pathogens. Several studies have focused on the microflora of farmed fishes, but the gut flora of wild fishes remains poorly characterized. The aim of this work was to provide an overview of the bacteria colonizing the gut of wild-caught fishes and to determine whether some bacterial species can be pathogenic. We isolated cultivable bacteria from fifteen wild-caught Mediterranean fish species corresponding to different habitat, diet and origin. Bacterial species identity was determined by 16s rRNA gene sequencing for the 61 isolates. The potential pathogenicity of isolated bacteria was investigated using fruit fly (Drosophila melanogaster) and zebrafish (Danio rerio) as model organisms. Two bacterial strains (Serratia sp. and Aeromonas salmonicida) were lethal when microinjected to Drosophila, while zebrafish did not develop any disease when exposed to any of 34 isolated bacterial strains. However, it was interesting to note that two bacterial strains (Shewanella and Arthrobacter) isolated from marine fishes were able to colonize the guts of freshwater zebrafish. The results of this study give an overview of the bacterial species found in the guts of wild fishes living off Beirut seashore. It shows that some parameters believed to be limiting factors to host-gut colonization by bacteria can be overcome by some species. This pilot study could be extended by sampling a larger number of fish species with several specimens per fish species, and by identifying uncultivable bacteria that reside in the fish guts. Our results may have implications for the utilization of certain bacterial species in fish farming or their use as bio-indicators for water and/or food quality.

  10. Assessment of spermatogenesis and plasma sex steroids in a seasonal breeding teleost: a comparative study in an area of influence of a tributary, downstream from a hydroelectric power dam, Brazil.

    Science.gov (United States)

    Domingos, Fabricio F T; Thomé, Ralph G; Arantes, Fabio P; Castro, Antonio Carlos S; Sato, Yoshimi; Bazzoli, Nilo; Rizzo, Elizete

    2012-12-01

    River damming and building of hydroelectric power plants interrupt the reproductive migration routes and change the major physicochemical parameters of water quality, with drastic consequences for populations of migratory fishes. The goal of this study was to evaluate proliferation and cell death during spermatogenesis and serum profiles of sex steroids in Prochilodus argenteus, from the São Francisco River, downstream from the Três Marias Dam. A total of 257 adult males were caught quarterly during a reproductive cycle in two sites: the first 34 km of the river after the dam (site 1) and the second 34-54 km after the dam (site 2), after the confluence with a tributary, the Abaeté River. Seasonal changes in the testicular activity associated with morphometric analyses of germ cells as well as proliferation and testicular apoptosis support a more active spermatogenesis in fish from site 2, where higher levels of sex steroids and gonadosomatic index (GSI) were also found. In site 1, fish presented low serum levels of testosterone, 17β-estradiol and 17α-hydroxyprogesterone and a low GSI during gonadal maturation. Spermatogonial proliferation (PCNA) and apoptosis (TUNEL) were more elevated in fish from site 1, but spermatocytes were mainly labelled in fish from site 2. Overall, these data demonstrate changes in testicular activity and plasma sex steroids in a neotropical teleost fish living downstream from a hydroelectric dam, supplying new data on fish reproduction in regulated rivers. Moreover, morphometric analyses associated with sex steroids profiles provide reliable tools to assess fish spermatogenesis under environmental stress conditions.

  11. Detection of freshwater cyanotoxins and measurement of masked microcystins in tilapia from Southeast Asian aquaculture farms.

    Science.gov (United States)

    Greer, Brett; Maul, Ronald; Campbell, Katrina; Elliott, Christopher T

    2017-06-01

    Recently, there has been a rise in freshwater harmful algal blooms (HABs) globally, as well as increasing aquaculture practices. HABs can produce cyanotoxins, many of which are hepatotoxins. An ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for nine cyanotoxins across three classes including six microcystins, nodularin, cylindrospermopsin and anatoxin-a. The method was used to analyse free cyanotoxin(s) in muscle (n = 34), liver (n = 17) and egg (n = 9) tissue samples of 34 fish sourced from aquaculture farms in Southeast Asia. Conjugated microcystin was analysed by Lemieux oxidation to ascertain the total amount of microcystin present in muscle. Some tilapia accumulated free microcystin-LR in the muscle tissue at a mean of 15.45 μg/kg dry weight (dw), with total microcystin levels detected at a mean level of 110.1 μg/kg dw, indicating that the amount of conjugated or masked microcystin present in the fish muscle accounted for 85% of the total. Higher levels of cyanotoxin were detected in the livers, with approximately 60% of those tested being positive for microcystin-LR and microcystin-LF, along with cylindrospermopsin. Two fish from one of the aquaculture farms contained cylindrospermopsin in the eggs; the first time this has been reported. The estimated daily intake for free and total microcystins in fish muscle tissue was 2 and 14 times higher, respectively, than the tolerable daily intake value. This survey presents the requirement for further monitoring of cyanotoxins, including masked microcystins, in aquaculture farming in these regions and beyond, along with the implementation of guidelines to safeguard human health. Graphical abstract ᅟ.

  12. Water resource protection in Australia: Links between land use and river health with a focus on stubble farming systems

    Science.gov (United States)

    Bowmer, Kathleen H.

    2011-06-01

    SummaryStubble farming (conservation farming, minimum tillage, zero tillage) has increased in Australia over several decades with claims of improved productivity, landscape stability and environmental benefit including ecosystem services downstream, yet recent audits show a dramatic and general decline in river health. This review explores explanations for this apparent anomaly. Many confounding factors complicate interactions between land use and river condition and may disguise or over-ride the potential benefits of adoption of stubble systems or other improvements in agricultural land use practice. These factors include climate change and variability; land use changes including an increase in bushfires, growth of farm dams and afforestation; lag times between land use change and expression of benefits in river systems; use of inappropriate scale that disguises local benefit; variations in the extent of ecosystem resilience; impacts of river regulation; and impacts of introduced species. Additionally, the value of river condition and utility is complicated by different local or regional perceptions and by contrasting rural and urban outlooks. The use of indicators, risk frameworks and biophysical modelling may help elucidate the complex relationships between land use and downstream ecosystem impact. The strengthening of local, regional and catchment scale approaches is advocated. This includes the re-integration of land management and governance with water management and planning. It is encouraging that farmers are themselves developing systems to optimise trade-offs between on-farm activities and ecosystem service benefits. This approach needs to be supported and extended.

  13. The effectiveness of different intervention strategies for the prevention of zoonotic metacercariae infection in cultured fish

    DEFF Research Database (Denmark)

    Clausen, Jesper Hedegaard; Madsen, Henry; Murrell, Kenneth Darwin

    2013-01-01

    interventions was reduced 91.7% compared to before interventions. The intensity of FZT was also significantly lower in the pond management group, compared to the drug treatment group and the control group after interventions. The results demonstrate that improving farm and pond management practices can......Fish-borne zoonotic trematodes (FZT) are a major public health problem. It is estimated that in Vietnam 26,366 "disability-adjusted life years" (DALYs) are lost due to FZT. Fish from aquaculture are a main source of protein and of great economic importance in both rural and urban areas...... with two intervention groups; a drug treatment of human and animal groups and a farm management group (control of snail vectors and fecal pollution of pond). A third group (non-intervention) served as control. Fish were examined for FZT metacercariae prevalence and intensity before and after interventions...

  14. Granulomas caused by Mycobacterium sp. in farmed Turbot Scopthalmus maximus (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    D. JERONIMO

    2013-09-01

    Full Text Available Turbot, Scophthlalmus maximus, is a Pleuronectiformes fish that occurs in northeast Atlantic along the European coast and in the Mediterranean Sea and is produced in aquaculture since the last quarter of the twentieth century. During a survey conducted in a turbot fish farm nodular formations were occasionally observed in several organs, especially in the kidney and in the spleen. Microscopic observations showed that these nodules contained acid-fast bacilli. The molecular identification of the isolated bacteria conducted to the Mycobacterium genus. Although no abnormal mortalities were evident morbidity was observed. The normal development and welfare of infected fish decrease and the condition factor, the haematocrit and the haemoglobin concentration in blood decreases significantly with the increase of nodules abundance.

  15. Drawdown flushing of a hydroelectric reservoir on the Rhône River: Impacts on the fish community and implications for the sediment management.

    Science.gov (United States)

    Grimardias, David; Guillard, Jean; Cattanéo, Franck

    2017-07-15

    Sediment flushings of hydropower reservoirs are commonly performed to maintain water resource uses and ecosystem services, but may have strong impacts on fish communities. Despite the worldwide scope of this issue, very few studies report quantitative in situ evaluations of these impacts. In June 2012, the drawdown flushing of the Verbois reservoir (Rhône River) was performed and subsequent impacts on the fish community were assessed, both inside the reservoir (fish densities by hydroacoustic surveys) and downstream (short-term movement and survival of radio tracked adult fish). Results showed that after the flushing fish acoustic density decreased by 57% in the reservoir, and no recolonization process was observed over the following 16 months. Downstream of the dam, the global apparent survival of fish to the flushing was estimated at 74%, but differed between species. The nine-year delay from the previous flushing and thus the amount of sediments to remove were too stressful for the low-resilience fish community of the Rhône River. Alternative flushing schedules are discussed to reduce these impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. First isolation of hirame rhabdovirus from freshwater fish in Europe

    DEFF Research Database (Denmark)

    Borzym, E.; Matras, M.; Maj-Paluch, J.

    2014-01-01

    A rhabdovirus was isolated in cell culture inoculated with tissue material from diseased grayling, Thymallus thymallus (L.), originating from a fish farm affected by a mortality episode in Poland. Diagnostics tests showed that the virus was not related to novirhabdoviruses known in Europe, nor to...

  17. Assessing relationships between chemical exposure, parasite infection, fish health, and fish ecological status: a case study using chub (Leuciscus cephalus) in the Bílina River, Czech Republic.

    Science.gov (United States)

    Wenger, Michael; Ondracková, Markéta; Machala, Miroslav; Neca, Jirí; Hyrsl, Pavel; Simková, Andrea; Jurajda, Pavel; von der Ohe, Peter; Segner, Helmut

    2010-02-01

    Multiple stressor scenarios, as they are relevant in many watersheds, call for approaches extending beyond conventional chemical-focused approaches. The present study, investigated the fish population, represented by chub (Leuciscus cephalus), in the Bílina River (Czech Republic), which is impacted by various pollution sources and might pose a risk on the fish population. To confirm or reject this hypothesis it was examined whether there exists an association between abundance of chub and exposure to toxic chemicals as well as natural stressors, represented by parasites, and whether health-related suborganismal traits, namely, organ indices, tissue histopathology, and immune parameters, would help in revealing relationships between stressor impact and population status. Toxic pressure was assessed by the toxic unit approach, which gives an integrative estimate of toxic effect concentrations and by measuring the biomarkers cytochrome P4501A and vitellogenin, which indicate exposure to bioavailable arylhydrocarbon- or estrogen receptor ligands. Parasite pressure was estimated by determining abundance and species composition of ecto- and endoparasites of chub. Chub abundance was high upstream in the Bílina, low to zero in the middle stretches, and increased again downstream. Toxic pressure increased in the downstream direction, while parasite intensity decreased in this direction. Health status of chub did not differ clearly between up-, middle-, and downstream sites. Thus, it appears that neither toxic pressure nor parasite pressure nor their combination translates into a change of chub health status. By using varied assessment tools, this study provides evidence against a presumed causative role of toxicants impairing the fish ecological status of the Bílina River. Copyright 2009 SETAC.

  18. Reducing organic contamination of shallow areas in brackish lagoons during rearing fish in cages in polyculture

    Directory of Open Access Journals (Sweden)

    P. Shekk

    2017-07-01

    Full Text Available Purpose. The development of the technology of the controlled rearing of marine fish remains one of the priority strategic trends of development of national mariculture. A study of the possibility of using polyculture for cage culture has a particular interest. Joint cultivation of several species of fish in the same cage, as practice of fish farming has demonstrated, does not have a tangible positive effect. At the same time, the use of cages of special design can provide significant additional fish products through the use of additional aquaculture objects. The ecological state of water areas, where the cages are located, is of great importance. High fish stocking density and the use of artificial feeds can serve as a source of powerful biogenic and organic pollution, which is especially important for shallow water areas with weak water exchange. The purpose of the study is to develop the methods for joint fish production in cage mariculture capable to provide high fish production and to weaken organic pollution of shallow water areas where cage farms are located. Methodology. The studies were conducted in 1999 and 2004. Cages of special design (internal 10 m3 and external 18.75 m3 installed in the brackish Shabolat Lagoon were used for rearing, steelhead trout, haarder, grass goby and round goby in polyculture. The standard aquaculture research methods were used. For express-analysis of environment hydrochemical parameters in cage location area the following devices were used: "ECOTEST-2000 T" (О2, NO2, NO3, NH4, CO2, phosphates, pH; termooksimetr "АJА-101М" (Т; О2; "pH meter-150 M; Refractometer "ATAGO-100" (salinity and water density. Findings. The results of marine fish cultivation in cages in polyculture in the shallow Shabolat lagoon are presented. It has been shown that joint cultivation of salmon, mullet and gobies in specially designed cages in shallow marine lagoons allows using artificial and natural feeds more fully and

  19. Tracing Asian seabass individuals to single fish farms using microsatellites.

    Directory of Open Access Journals (Sweden)

    Gen Hua Yue

    Full Text Available Traceability through physical labels is well established, but it is not highly reliable as physical labels can be easily changed or lost. Application of DNA markers to the traceability of food plays an increasingly important role for consumer protection and confidence building. In this study, we tested the efficiency of 16 polymorphic microsatellites and their combinations for tracing 368 fish to four populations where they originated. Using the maximum likelihood and Bayesian methods, three most efficient microsatellites were required to assign over 95% of fish to the correct populations. Selection of markers based on the assignment score estimated with the software WHICHLOCI was most effective in choosing markers for individual assignment, followed by the selection based on the allele number of individual markers. By combining rapid DNA extraction, and high-throughput genotyping of selected microsatellites, it is possible to conduct routine genetic traceability with high accuracy in Asian seabass.

  20. Trading-off fish biodiversity, food security, and hydropower in the Mekong River Basin.

    Science.gov (United States)

    Ziv, Guy; Baran, Eric; Nam, So; Rodríguez-Iturbe, Ignacio; Levin, Simon A

    2012-04-10

    The Mekong River Basin, site of the biggest inland fishery in the world, is undergoing massive hydropower development. Planned dams will block critical fish migration routes between the river's downstream floodplains and upstream tributaries. Here we estimate fish biomass and biodiversity losses in numerous damming scenarios using a simple ecological model of fish migration. Our framework allows detailing trade-offs between dam locations, power production, and impacts on fish resources. We find that the completion of 78 dams on tributaries, which have not previously been subject to strategic analysis, would have catastrophic impacts on fish productivity and biodiversity. Our results argue for reassessment of several dams planned, and call for a new regional agreement on tributary development of the Mekong River Basin.

  1. Biomarker analyses in caged and wild fish suggest exposure to pollutants in an urban area with a landfill.

    Science.gov (United States)

    Hanson, Niklas; Larsson, Åke

    2011-06-01

    An unexpectedly high frequency of skeletal deformations in brown trout has previously been observed in the brook Vallkärrabäcken in southern Sweden. Environmental pollutants from storm water and leachate from an old landfill have been suggested as responsible for the observed deformations. Biomarkers in farmed rainbow trout, placed in tanks with water supplied from the brook, were used to investigate if exposure to pollutants may induce toxic responses in fish. Furthermore, biomarkers were also measured in wild brown trout that were caught in the brook. The most important finding was that the hepatic ethoxyresorufin-O-deethylase (EROD) activity was five to seven times higher for rainbow trout and brown trout in exposed areas compared to reference sites (Ppollution in parts of Vallkärrabäcken. It is therefore possible that the previously observed high frequency of skeletal damage have been caused by pollutants. The methodology with farmed rainbow trout in flow through tanks worked well and provided more information about the occurrence of pollutants in Vallkärrabäcken than the data from brown trout. The main reasons for this were that the size and the feeding status of the fish could be controlled. This allowed a total of 21 biomarkers to be analyzed in farmed rainbow trout compared to only five in wild brown trout. Furthermore, the use of farmed fish eliminates the risk of migration, which may otherwise bias the data when wild fish are used. © 2010 Wiley Periodicals, Inc.

  2. Histopathology and culturable bacteria associated with "big belly" and "skin nodule" syndromes in ornamental Siamese fighting fish, Betta splendens.

    Science.gov (United States)

    Dong, H T; Senapin, S; Phiwsaiya, K; Techatanakitarnan, C; Dokladda, K; Ruenwongsa, P; Panijpan, B

    2018-06-02

    The Siamese fighting fish (Betta splendens) is one of the popular aquarium ornamental fish in the global trade. Large numbers of ornamental fish farmed in central Thailand suffered from two common syndromes; preliminarily named skin nodule syndrome (SNS) and big belly syndrome (BBS): they showed noticeable clinical signs of abnormal appearances resulting in depressed saleability. Since very few specifics are known about causative agents of these syndromes, this study aimed at investigating histopathological features and culturable bacteria associated with these fish infected in the process of farming. Histopathologically, SNS fish consistently exhibited necrosis and severe melanization in the muscles and multiple internal organs. Whereas BBS fish exhibited either typical granulomas or tissue damage associated with acid-fast stained bacteria and Gram negative bacteria, respectively. Six different Gram negative bacterial species were recovered from BBS fish while 23 bacterial species belonging to 14 genera were recovered from fish suffering from SNS. Most of the culturable bacteria are new to betta fish and some of them are known to be marine bacteria, suggesting possible entry route via a contaminated live feed, commercial Artemia shrimp. The true causative agents of these syndromes remain unclear. However, histopathological changes and existence of a wide range of bacteria associated with the naturally diseased fish suggest involvement of multiple bacterial infections. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Investigation of a plant and fish kill downstream from BNL sewage treatment outfall

    International Nuclear Information System (INIS)

    Hull, A.P.

    1975-01-01

    During the period May 13 to May 17, 1974, a plant and fish kill occurred in a headwater of the Peconic River, which originates on the Brookhaven National Laboratory (BNL) site. Although the stream itself, and hence the magnitude of the mortality, was small, the fish kill was near total in the impacted reach, and therefore received more attention than the numbers alone would warrant. The Laboratory has utilized the stream for the past 25 years for the discharge of treated sanitary wastes containing low levels of radioactivity, without perceptible effect up to the time of this incident. Although an investigation during the following several months has not disclosed a completely satisfactory explanation, it has pointed out weaknesses in the Laboratory's knowledge of the on site amounts and locations of environmentally toxic agents, as well as of the accountability for their use. The investigation also suggested the need for additional monitoring to detect unusual agents in the sanitary treatment plant influent for prompt analyses of suspect samples, and for a means of holding up the effluent until such analyses can be accomplished. Additionally, the investigation led to the identification of supporting analytical capabilities of other government agencies, without which a competent investigation would have been difficult. It also revealed the desirability for the prompt submission of relevant samples to them, in the event of a recurrence

  4. Effects of Harmful Algae on the Physiology of Fishes

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo Søndergaard

    Blooms of harmful planktonic algae causing adverse effects in aquatic environments are a global problem, causing both human morbidity and killing aquatic lifeforms worldwide. Focusing on fish kills, it is largely unknown what mechanisms of the fish’s physiology are affected during exposure...... is deemed unlikely on basis of rainbow trout (Onchorhyncus mykiss) not recovering. The specific toxicity of Pseudochattonella spp. is unknown, but by studying the effects of Pseudochattonella spp. on fish during a natural bloom occurring at a trout farm an adverse outcome could be created. The adverse...... Alexandrium monilatum has been studied intensively the effects of Alexandrium monilatum on fish is largely unknown. In the Chesapeake Bay, Eastern U.S.A., fishes are further challenged in late summer by an oxygen squeeze from deep part of the water column, limiting their utilizable habitat to mid...

  5. Screening for Viral Hemorrhagic Septicemia Virus in Marine Fish along the Norwegian Coastal Line

    DEFF Research Database (Denmark)

    Sandlund, Nina; Gjerset, Britt; Bergh, Øivind

    2014-01-01

    Viral hemorrhagic septicemia virus (VHSV) infects a wide range of marine fish species. To study the occurrence of VHSV in wild marine fish populations in Norwegian coastal waters and fjord systems a total of 1927 fish from 39 different species were sampled through 5 research cruises conducted......, and to our knowledge the first detection of VHSV in silvery pout. However, low prevalence of VHSV genotype Ib in Atlantic herring and other wild marine fish are well known in other parts of Europe. Earlier there have been a few reports of disease outbreaks in farmed rainbow trout with VHSV of genotype Ib...

  6. Readily Available Sources of Long-Chain Omega-3 Oils: Is Farmed Australian Seafood a Better Source of the Good Oil than Wild-Caught Seafood?

    Directory of Open Access Journals (Sweden)

    Peter D. Nichols

    2014-03-01

    Full Text Available Seafood consumption enhances intake of omega-3 long-chain (≥C20 polyunsaturated fatty acids (termed LC omega-3 oils. Humans biosynthesize only small amounts of LC-omega-3, so they are considered semi-essential nutrients in our diet. Concern has been raised that farmed fish now contain lower LC omega-3 content than wild-harvested seafood due to the use of oil blending in diets fed to farmed fish. However, we observed that two major Australian farmed finfish species, Atlantic salmon (Salmo salar and barramundi (Lates calcifer, have higher oil and LC omega-3 content than the same or other species from the wild, and remain an excellent means to achieve substantial intake of LC omega-3 oils. Notwithstanding, LC omega-3 oil content has decreased in these two farmed species, due largely to replacing dietary fish oil with poultry oil. For Atlantic salmon, LC omega-3 content decreased ~30%–50% between 2002 and 2013, and the omega-3/omega-6 ratio also decreased (>5:1 to <1:1. Australian consumers increasingly seek their LC omega-3 from supplements, therefore a range of supplement products were compared. The development and future application of oilseeds containing LC omega-3 oils and their incorporation in aquafeeds would allow these health-benefitting oils to be maximized in farmed Australian seafood. Such advances can assist with preventative health care, fisheries management, aquaculture nutrition, an innovative feed/food industry and ultimately towards improved consumer health.

  7. Screening level dose assessment of aquatic biota downstream of the Marcoule nuclear complex in southern France.

    Science.gov (United States)

    St-Pierre, S; Chambers, D B; Lowe, L M; Bontoux, J G

    1999-09-01

    Aquatic biota in the Rhone River downstream of the Marcoule nuclear complex in France are exposed to natural sources of radiation and to radioactivity released from the Marcoule complex. A simple conservative screening level model was used to estimate the range of concentrations in aquatic media (water, sediments, and aquatic organisms) of both artificial and natural radionuclides and the consequent absorbed (whole body) dose rates for aquatic organisms. Five categories of aquatic organisms were studied, namely, submerged aquatic plants (phanerogam), non-bottom-feeding fish, bottom-feeding fish, mollusca, and fish-eating birds. The analysis was based on the radionuclide concentrations reported in four consecutive annual radioecological monitoring reports published by French agencies with nuclear regulatory responsibilities. The results of this assessment were used to determine, qualitatively, the magnitude of any potential health impacts on each of the five categories of aquatic organisms studied. The range of dose rate estimates ranged over three orders of magnitude, with maximum dose rates estimated to be in the order of 1 to 10 microGy h(-1). These maximum dose rates are a factor 40 or more below the international guideline intended to ensure the protection of aquatic populations (about 400 microGy h(-1)), and a factor ten or more below the level which may trigger the need for a more detailed evaluation of potential ecological consequences to the exposed populations (about 100 microGy h(-1)). As a result, chronic levels of radioactivity, artificial and natural, measured in aquatic media downstream of Marcoule are unlikely to result in adverse health impacts on the categories and species of aquatic organisms studied. Thus, based on the screening level analysis discussed in this paper, a more detailed evaluation of the dose rates does not appear to be warranted.

  8. Seacage aquaculture in a World Heritage Area: The environmental footprint of a Barramundi farm in tropical Australia

    International Nuclear Information System (INIS)

    McKinnon, A. David; Trott, Lindsay A.; Brinkman, Richard; Duggan, Samantha; Castine, Sarah; O'Leary, Rebecca A.; Alongi, Daniel M.

    2010-01-01

    The fate of aquaculture wastes from a seacage farm within a pristine mangrove environment was studied. Seasonal and tidal differences were most important in determining water quality within receiving waters and obscured any nutrient enrichment effect by the farm. Farm wastes added significantly to the N budget status of the creek system, but overall water quality conformed to Queensland EPA Water Quality standards. Mangrove trees throughout the creek system contained 15 N signatures traceable to aquaculture feeds, but the footprint of the farm itself was best indicated by the ratio of Zn:Li in sediments. The creek became hypoxic ( -1 ) during wet season low tides. Consequently, we recommended monitoring of water-column oxygen concentrations to warn of hypoxic conditions threatening to fish health, as well as Zn:Li ratios in sediment accumulation zones to determine the area of influence of the farm.

  9. An analysis of the tritium content in fish from Upper Three Runs Creek

    International Nuclear Information System (INIS)

    Murphy, C.E. Jr.

    1991-01-01

    In November of 1988 the F/H-area effluent treatment facility (ETF) began releasing treated waste water to Upper Three Runs Creek. Previous to that time, there has been minimal discharge of plant waste water to this tributary of the Savannah River. The ETF is designed to remove the toxic and radioactive waste materials from the effluent stream and to meet the discharge limits of the South Carolina Department of Health and Environmental Control (SCDHEC). The only radioactive nuclide not removed by the process is tritium. Tritium, an isotope of hydrogen, is chemically associated with the water molecules in the waste stream and can not be economically removed at this time. The objective of this study was to determine the relationship between the concentration of tritium in the stream water and the concentration of tritium in the fish. Fish collections were made at two locations. The most upstream location was 50 meters downstream from the SRS Road C bridge. This is immediately downstream of the effluent discharge pipe from the ETF. The other location was at the bridge of SRS Road A (SC Highway 125). The water is removed from the fish by freeze drying under vacuum. This study suggests that, on the average, the tritium concentration of fish in Upper Three Runs Creek will be in equilibrium with the tritium in the water of the creek. The water in the fish comes into equilibrium with the water in the stream quite rapidly and it is quite likely that any single fish sampled will be higher or lower in tritium content of an integrated water sample, such as those collected by the Environmental Monitoring samplers. Both the time of sampling and the sampling of a sufficient number of fish is important in obtaining an accurate estimate of the average tritium concentration in the tissue water of the fish

  10. It is the economy, stupid! Projecting the fate of fish populations using ecological-economic modeling.

    Science.gov (United States)

    Quaas, Martin F; Reusch, Thorsten B H; Schmidt, Jörn O; Tahvonen, Olli; Voss, Rudi

    2016-01-01

    Four marine fish species are among the most important on the world market: cod, salmon, tuna, and sea bass. While the supply of North American and European markets for two of these species - Atlantic salmon and European sea bass - mainly comes from fish farming, Atlantic cod and tunas are mainly caught from wild stocks. We address the question what will be the status of these wild stocks in the midterm future, in the year 2048, to be specific. Whereas the effects of climate change and ecological driving forces on fish stocks have already gained much attention, our prime interest is in studying the effects of changing economic drivers, as well as the impact of variable management effectiveness. Using a process-based ecological-economic multispecies optimization model, we assess the future stock status under different scenarios of change. We simulate (i) technological progress in fishing, (ii) increasing demand for fish, and (iii) increasing supply of farmed fish, as well as the interplay of these driving forces under different scenarios of (limited) fishery management effectiveness. We find that economic change has a substantial effect on fish populations. Increasing aquaculture production can dampen the fishing pressure on wild stocks, but this effect is likely to be overwhelmed by increasing demand and technological progress, both increasing fishing pressure. The only solution to avoid collapse of the majority of stocks is institutional change to improve management effectiveness significantly above the current state. We conclude that full recognition of economic drivers of change will be needed to successfully develop an integrated ecosystem management and to sustain the wild fish stocks until 2048 and beyond. © 2015 John Wiley & Sons Ltd.

  11. The financial feasibility of producing fish and vegetables through aquaponics

    NARCIS (Netherlands)

    Bosma, Roel H.; Lacambra, Lysette; Landstra, Ynze; Perini, Chiara; Poulie, Joline; Schwaner, Marie J.; Yin, Yi

    2017-01-01

    Aquaponics, producing fish and vegetables in a closed-loop water system, reduces fertilizer use and water discharge, and is therefore promoted as a sustainable venture. A recent global study found that the majority of 257 surveyed aquaponics farms made losses, but the reasons have been poorly

  12. INFLUENCE OF CARP BREEDING ON PHYSICOCHEMICAL STATE OF WATER IN FISH POND AND RECEIVE

    Directory of Open Access Journals (Sweden)

    Włodzimierz Kanownik

    2015-10-01

    Full Text Available The paper presents the results of tests on quality features of feeding water and fish ponds of Mydlniki fish farm in the małopolskie province. The measurement and control points are situated in the river Rudawa before and below the farm and in four breeding ponds were measured in water: temperature, concentrations of dissolved oxygen, electrolytic conductivity, pH, total suspended solids, dissolved solids and concentrations of minerals: SO42+, Cl-, Ca2+, Mg2+, Na+, K+, Fe i Mn, and also biogenic compounds (PO43-, N-NH4+, N-NO2-, N-NO3-. It was found that water from the Rudawa river feeding the ponds did not meet the requirements for inland waters which are the natural environment for the cyprinids. The physicochemical state is below the well due to the high concentration of phosphate. Statistical analysis of 19 tested features revealed a positive effect of the fish ponds on water quality. Concentrations of biogenic compounds (phosphate, nitrite and nitrate nitrogen, dissolved solids, calcium and water conductivity in the fish ponds decreased on average by between 30 and 87% in comparison with the feeding watercourse.

  13. Persistence of herpesvirus of eel (Herpesvirus anguillae) in farmed European ell (Anguilla anguilla L.)

    NARCIS (Netherlands)

    Nieuwstadt, van A.P.; Dijkstra, S.G.; Haenen, O.L.M.

    2001-01-01

    Herpesvirus of eel Herpesvirus anguillae (HVA) was isolated repeatedly from farmed eel of an outwardly healthy stock, but virus isolation was much greater in an experimental group of fish that were injected with dexamethasone. The results suggest that HVA can establish a latent infection in eel.

  14. Downstream process for production of a viable and stable Bacillus cereus aquaculture biological agent

    CSIR Research Space (South Africa)

    Lalloo, R

    2010-03-01

    Full Text Available , 604 Robertson JL (1998) The use of probiotics in the diet of dogs. 605 J Nutri 128:2730S–2732S 606 Brar SK, Verma M, Tyagi RD, Valéro JR (2006) Recent advances in 607 downstream processing and formulations of Bacillus thuringien- 608 sis based..., Menasveta P (2000) Some recent issues and innovations in 630 marine shrimp pond culture. Rev Fish Sci 8:151–233 631 Gatesoupe FJ (1999) The use of probiotics in aquaculture. Aquacul- 632 ture 180:147–165 633 Guetsky R, Shtienberg Y, Elad Y, Fischer E...

  15. Post-harvest loss of farm raised Indian and Chinese major carps in the distribution channel from Mymensingh to Rangpur of Bangladesh.

    Science.gov (United States)

    Hossain, M Motaleb; Rahman, Mahabubur; Hassan, M Nazmul; Nowsad, A A K M

    2013-06-15

    Post-harvest loss of catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigala), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella) and sarpunti (Puntius sarana) in a single distribution chain from harvest in Mymensingh to retail sale Rangpur town were determined, in order to obtain information on quality deterioration and existing handling and icing conditions so that suggestions for improving such practices can be made. Quality defect points of the fish at different steps of distribution channels were determined using a sensory based quality assessment tool. Percent quality loss of fish at each step of distribution was calculated from the number of cases that crossed sensory quality cut-off points. Neither of the fish lost their quality when they were in the farm gate, during transportation and in wholesale markets in Rangpur but most of the fishes lost their quality at the retail fish shops. The quality loss was 8, 12, 8, 6, 10 and 14% in case of C. catla, C. mrigala, L. rohita, H. molitrix, C. idella and P. sarana respectively in the retail markets. Fishes were not properly handled, bamboo baskets wrapped with polythene sheet were used as carrying container and inadequate ice was used during transportation. Retailers were found to be more proactive in the use of ice. However, most of the fishes were deteriorated during retail sale. The losses of farmed fishes could be minimized by adopting good handling practices like using insulated container and adequate icing.

  16. Comparative analysis of selected semi-persistent and emerging pollutants in wild-caught fish and aquaculture associated fish using Bogue (Boops boops) as sentinel species.

    Science.gov (United States)

    Henríquez-Hernández, Luis Alberto; Montero, Daniel; Camacho, María; Ginés, Rafael; Boada, Luis D; Ramírez Bordón, Besay; Valerón, Pilar F; Almeida-González, Maira; Zumbado, Manuel; Haroun, Ricardo; Luzardo, Octavio P

    2017-03-01

    The marine environment acts as a sink for diverse anthropogenic pollutants, although the environmental contamination may be non-uniformly distributed. In recent decades, the aquaculture sector has experienced a steady growth postulating as a good alternative for seafood production. However, a social debate exits about the differential level of pollutants in wild and farmed species. This study was designed to evaluate the level of pollutants in a sentinel species: Bogue (Boops boops) associated and non-associated to fish-farm cages. A total of 82 chemical substances were determined by gas chromatography-mass spectrometry, including persistent (polychlorobiphenyls (PCBs) and organochlorine pesticides (OCPs)), semi-persistent (bromodiphenyl ethers (BDEs) and polycyclic aromatic hydrocarbons (PAHs)), and emerging pollutants (such as organophosphate flame retardants (OPFRs) and UV-filters). In general, aquaculture-associated bogues showed lower levels of semi-persistent and emerging pollutants than wild-caught fish, especially when sums were considered. Thus, sum of BDEs was significantly lower in the aquaculture group (p=0.01). A similar trend was also observed for benzo(a)anthracene, the UV-filter 2-ethylhexyl-p-methoxycinnamate and some OPFRs. In the case of persistent pollutants, the sum of dioxin-like PCBs and sum of DDTs were lower in the group of wild-caught bogues (p=0.034 and p=0.003, respectively) than in aquaculture-associated bogues, as previously described for some aquaculture species. Fish feed appear as an important factor in the uptake of such substances suggesting a diet intervention to reduce their levels in the aquaculture products. Another interesting result is that for almost all chemical substances analyzed, bogues captured near sewage outfalls showed the highest levels of pollutants, pointing out the need of stringent measures for wastewater treatment units discharging in coastal areas. On the light of these results, further research in specific

  17. Fish oil extracted from fish-fillet by-products is weakly linked to the extraction temperatures but strongly linked to the omega-3 content of the raw material

    DEFF Research Database (Denmark)

    Honold, Philipp; Nouard, Marie-Louise; Jacobsen, Charlotte

    2016-01-01

    Rainbow trout (Oncorhynchus mykiss) is the mainspecies produced in Danish fresh water farming. Therefore, a large amount of fileting by-products like heads, bones, and tails (HBT) and intestines are available and can be used to produce high quality fish oil. The main aim in this study was to inve......Rainbow trout (Oncorhynchus mykiss) is the mainspecies produced in Danish fresh water farming. Therefore, a large amount of fileting by-products like heads, bones, and tails (HBT) and intestines are available and can be used to produce high quality fish oil. The main aim in this study...... products, % free fatty acids as well as content of omega-3 PUFA. Furthermore, an experiment was carried out to elucidate the effect of extraction temperature on oil produced from raw materials with a different content of omega-3 fatty acids. For this purpose filleting by-products from conventional (low...

  18. [Estimation of spur dike-affected fish habitat area].

    Science.gov (United States)

    Ray-Shyan, Wu; Yan-Ru, Chen; Yi-Liang, Ge

    2012-04-01

    Based on the HEC-RAS and River 2D modes, and taking 5% change rate of weighted usable area (WUA) as the threshold to define the spur dike- affected area of target fish species Acrossocheilus paradoxus in Fazi River in Taiwan, this paper studied the affected area of the fish habitat by spur dike, and, in combining with the references about the installations of spur dikes in Taiwan in recent 10 years, analyzed the relative importance of related affecting factors such as dike height, dike length (water block rate), average slope gradient of river way, single or double spur dike, and flow discharge. In spite of the length of the dike, the affected area in downstream was farther, and was about 2-6 times as large as that in upstream. The ratio of the affected area in downstream / upstream decreased with increasing slope gradient, but increased with increasing dike length and flow discharge. When the discharge was approximate to 10 years return periods, the ratio of the affected area would be close to a constant of 2. Building double spur dike would produce a better WUA than building single spur dike.

  19. Selection for adaptation to dietary shifts: towards sustainable breeding of carnivorous fish.

    Directory of Open Access Journals (Sweden)

    Richard Le Boucher

    Full Text Available Genetic adaptation to dietary environments is a key process in the evolution of natural populations and is of great interest in animal breeding. In fish farming, the use of fish meal and fish oil has been widely challenged, leading to the rapidly increasing use of plant-based products in feed. However, high substitution rates impair fish health and growth in carnivorous species. We demonstrated that survival rate, mean body weight and biomass can be improved in rainbow trout (Oncorhynchus mykiss after a single generation of selection for the ability to adapt to a totally plant-based diet (15.1%, 35.3% and 54.4%, respectively. Individual variability in the ability to adapt to major diet changes can be effectively used to promote fish welfare and a more sustainable aquaculture.

  20. Molecular detection of Aeromonas hydrophila in the aquarium gold fish and cultured rainbow trout in Chaharmahal va Bakhtiary province

    Directory of Open Access Journals (Sweden)

    firouz Fadaeifard

    2014-05-01

    Full Text Available Aeromonas hydrophilia   is the etiologic agent of motile aeromonas septicaemia, one of the most important bacterial diseases of fresh and marine water fishes. The aim of the present study was detection of A. hydrophilia in the aquarium goldfish and cultured rainbow trout in Chaharmahal va Bakhtiary province.  In this study 50 goldfish from aquarium fish shops and 60 rainbow trouts suspected of having the disease from 6 farms (10 fish in each farm were randomly collected. The average weight in goldfish and rainbow trout samples were 3-5 g and 10-20 g, respectively. Sampling was performed from kidney and liver, and inoculated into blood agar and incubated at 22°C for 24 hours. Pure colonies which are grown on the mediums were tested by catalase, oxidase and gram staining, then those of gram-negative, catalase and oxidase positive were diagnosed, and cultured on Shotts-Rimler medium (as selective medium for A. hydrophila. These mediums were incubated at 22 °C for 24-48 h. The typical colonies were tested by using oligonucleotide primers of lip gene by PCR method. In light of molecular analysis of all specimens, 9 and 6 isolates from rainbow trout and gold fishes were identified as A. hydrophila respectively. Due to the detection of A. hydrophila in both cultured rainbow trout and aquarium goldfish, the bacteria can lead to septicemia with mortality if the health management principles are not observed in fish farming.

  1. Influence of environmental factors on fish production in Ogun-State ...

    African Journals Online (AJOL)

    The study investigated environmental factors influencing fish farming in Ijebu - Ode Local Government Area (LGA) of Ogun-state, Nigeria. Data were obtained from 50 respondents selected from 10 ponds in the area of study. Respondents were selected for the study using random sampling technique while the ponds ...

  2. Women's independent access to productive resources: fish ponds in the Oxbow Lakes Project, Bangladesh.

    Science.gov (United States)

    Nathan, D; Apu, N A

    1998-01-01

    This article analyzes the experiences of women in acquiring user rights to fish ponds on government owned lands in the Oxbow Lakes Project in Bangladesh. The analysis describes the significance, functioning, and problems of women in fish farming. The field reports were based on the authors' involvement in implementation of the extension of fishing rights to women during 6 weeks/year over 4 years. Analysis was based on observations and discussions during project implementation and on a survey conducted in March 1997. The project involved land reforms that transferred rights to a group of poor people. Most of the lakes had been overfished. The poor fishers were organized into Lake Fishing Teams (LFTs) with the right to culture and harvest fish in lakes that were under common property management. In late 1994, at least 50% of the women were included in the Fish Farming Groups (FFGs) to manage fish culture in ponds constructed in shallow areas of the lake shore. The proportion of women was increased to 75% in 1994-95 and favored women-headed households. By March 1997, there were 510 members of FFGs, of whom 84% were single, poor women. Women had low participation in fish sales and netting and guarding the harvest. Women in mixed gender groups complained that men dominated the key decision-making and financial areas. Production averaged 1500 kg/hectare in 1995-96. FFGs had higher expenses for feed and fertilizer than LFTs. This endeavor earned higher per capita income than poultry raising. All women groups performed better than mixed groups. These groups increased assertiveness and self-confidence.

  3. Screening for viral hemorrhagic septicemia virus in marine fish along the Norwegian coastal line.

    Directory of Open Access Journals (Sweden)

    Nina Sandlund

    Full Text Available Viral hemorrhagic septicemia virus (VHSV infects a wide range of marine fish species. To study the occurrence of VHSV in wild marine fish populations in Norwegian coastal waters and fjord systems a total of 1927 fish from 39 different species were sampled through 5 research cruises conducted in 2009 to 2011. In total, VHSV was detected by rRT-PCR in twelve samples originating from Atlantic herring (Clupea harengus, haddock (Melanogrammus aeglefinus, whiting (Merlangius merlangus and silvery pout (Gadiculus argenteus. All fish tested positive in gills while four herring and one silvery pout also tested positive in internal organs. Successful virus isolation in cell culture was only obtained from one pooled Atlantic herring sample which shows that today's PCR methodology have a much higher sensitivity than cell culture for detection of VHSV. Sequencing revealed that the positive samples belonged to VHSV genotype Ib and phylogenetic analysis shows that the isolate from Atlantic herring and silvery pout are closely related. All positive fish were sampled in the same area in the northern county of Finnmark. This is the first detection of VHSV in Atlantic herring this far north, and to our knowledge the first detection of VHSV in silvery pout. However, low prevalence of VHSV genotype Ib in Atlantic herring and other wild marine fish are well known in other parts of Europe. Earlier there have been a few reports of disease outbreaks in farmed rainbow trout with VHSV of genotype Ib, and our results show that there is a possibility of transfer of VHSV from wild to farmed fish along the Norwegian coast line. The impact of VHSV on wild fish is not well documented.

  4. Genetic Detection of Pseudomonas spp. in Commercial Amazonian Fish

    Science.gov (United States)

    Ardura, Alba; Linde, Ana R.; Garcia-Vazquez, Eva

    2013-01-01

    Brazilian freshwater fish caught from large drainages like the River Amazon represent a million ton market in expansion, which is of enormous importance for export to other continents as exotic seafood. A guarantee of bacteriological safety is required for international exports that comprise a set of different bacteria but not any Pseudomonas. However, diarrhoea, infections and even septicaemia caused by some Pseudomonas species have been reported, especially in immune-depressed patients. In this work we have employed PCR-based methodology for identifying Pseudomonas species in commercial fish caught from two different areas within the Amazon basin. Most fish caught from the downstream tributary River Tapajòs were contaminated by five different Pseudomonas species. All fish samples obtained from the River Negro tributary (Manaus markets) contained Pseudomonas, but a less diverse community with only two species. The most dangerous Pseudomonas species for human health, P. aeruginosa, was not found and consumption of these fish (from their Pseudomonas content) can be considered safe for healthy consumers. As a precautionary approach we suggest considering Pseudomonas in routine bacteriological surveys of imported seafood. PMID:24065035

  5. Dioxins, dioxin-like PCBs and organochlorine pesticides in farmed salmon of various origin

    Energy Technology Data Exchange (ETDEWEB)

    Karl, H. [Bundesforschungszentrum fuer Ernaehrung und Nahrung, Hamburg (Germany); Ruoff, U. [Bundesforschungszentrum fuer Ernaehrung und Nahrung, Kiel (Germany); Schwind, K.H.; Jira, W. [Bundesforschungszentrum fuer Ernaehrung und Nahrung, Kulmbach (Germany)

    2004-09-15

    With a market share of 8.4% in 2001 (approx. 100,000 t) farmed salmon is one of the most important fish species on the German market. The world wide production of salmon in 2001 was approximately 1.2 Mio t. Norway has produced around 450,000 t of Atlantic salmon of which 60,000 t has been exported to Germany. Other important suppliers of salmon to the German market are Scotland, Denmark, Chile and Ireland. The annual amount from Ireland is relatively small, being approximately 2,000 t. Most salmon is raised under conventional farming conditions. During the last years also high priced organically grown salmon is available on the German market, mainly produced in Ireland. With 800 t per year the market share of organically farmed salmon is less than 1%. Within the context of a study to develop methods for the detection of organically produced products taking salmon as example it was checked if the contaminant levels and/or the contaminant patterns are suitable to differentiate between organically and conventionally farmed salmon. Conventionally farmed salmon, referred as to farmed salmon, was collected from different European farms; organically farmed salmon, referred as to organic salmon, came from Ireland as well as wild Atlantic salmon, which was included into the study. In the present study dioxins, dioxin-like PCBs, marker PCBs and a range of organochlorine pesticides (toxaphene, chlordane, DDT, HCB etc.) in the muscle meat of salmon were investigated.

  6. Family fish farming improves quality of life in the Bolivian Amazon

    International Development Research Centre (IDRC) Digital Library (Canada)

    de Piscicultores del Norte Integrado en Yapacaní. (Yapacani ... para la Promoción Agropecuaria Campesina. (Centre for Rural ... inclusion of fish, an affordable source of high quality protein. .... Revista de la Facultad de Medicina. Veterinaria y ...

  7. Oral vaccination of fish: Lessons from humans and veterinary species.

    Science.gov (United States)

    Embregts, Carmen W E; Forlenza, Maria

    2016-11-01

    The limited number of oral vaccines currently approved for use in humans and veterinary species clearly illustrates that development of efficacious and safe oral vaccines has been a challenge not only for fish immunologists. The insufficient efficacy of oral vaccines is partly due to antigen breakdown in the harsh gastric environment, but also to the high tolerogenic gut environment and to inadequate vaccine design. In this review we discuss current approaches used to develop oral vaccines for mass vaccination of farmed fish species. Furthermore, using various examples from the human and veterinary vaccine development, we propose additional approaches to fish vaccine design also considering recent advances in fish mucosal immunology and novel molecular tools. Finally, we discuss the pros and cons of using the zebrafish as a pre-screening animal model to potentially speed up vaccine design and testing for aquaculture fish species. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Real time fish pond monitoring and automation using Arduino

    Science.gov (United States)

    Harun, Z.; Reda, E.; Hashim, H.

    2018-03-01

    Investment and operating costs are the biggest obstacles in modernizing fish ponds in an otherwise very lucrative industry i.e. food production, in this region. Small-scale farmers running on small ponds could not afford to hire workers to man daily operations which usually consists of monitoring water levels, temperature and feeding fish. Bigger scale enterprises usually have some kinds of automation for water monitoring and replacement. These entities have to consider employing pH and dissolved oxygen (DO) sensors to ensure the health and growth of fish, sooner or later as their farms grow. This project identifies one of the sites, located in Malacca. In this project, water, temperature, pH and DO levels are measured and integrated with aerating and water supply pumps using Arduino. User could receive information at predetermined intervals on preferred communication or display gadgets as long as they have internet. Since integrating devices are comparatively not expensive; it usually consists of Arduino board, internet and relay frames and display system, farmer could source these components easily. A sample of two days measurements of temperature, pH and DO levels show that this farm has a high-quality water. Oxygen levels increases in the day as sunshine supports photosynthesis in the pond. With this integration system, farmer need not hire worker at their site, consequently drive down operating costs and improve efficiency.

  9. Habitat quality and recruitment success of cui-ui in the Truckee River downstream of Marble Bluff Dam, Pyramid Lake, Nevada

    Science.gov (United States)

    Scoppettone, G. Gary; Rissler, Peter H.; Salgado, J. Antonio; Harry, Beverly

    2013-01-01

    We compared cui-ui (Chasmistes cujus) recruitment from two reaches of the Truckee River with histories of severe erosional downcutting caused by a decline in Pyramid Lake surface elevation. In 1975, Marble Bluff Dam (MBD) was constructed 5 kilometers upstream of the extant mouth of the Truckee River to stabilize the upstream reach of the river; the downstream reach of the river remained unstable and consequently unsuitable for cui-ui recruitment. By the early 2000s, there was a decrease in the Truckee River’s slope from MBD to Pyramid Lake after a series of wet years in the 1990s. This was followed by changes in river morphology and erosion abatement. These changes led to the question as to cui-ui recruitment potential in the Truckee River downstream of MBD. In 2012, more than 7,000 cui-ui spawners were passed upstream of MBD, although an indeterminate number of cui-ui spawned downstream of MBD. In this study, we compared cui-ui recruitment upstream and downstream of MBD during a Truckee River low-flow year (2012). Cui-ui larvae emigration to Pyramid Lake began earlier and ended later downstream of MBD. A greater number of cui-ui larvae was produced downstream of MBD than upstream. This also was true for native Tahoe sucker (Catostomus tahoensis) and Lahontan redside (Richardsonius egregius). The improved Truckee River stability downstream of MBD and concomitant cui-ui recruitment success is attributed to a rise in Pyramid Lake's surface elevation. A decline in lake elevation may lead to a shift in stream morphology and substrate composition to the detriment of cui-ui reproductive success as well as the reproductive success of other native fishes.

  10. Fish ladder of Lajeado Dam: migrations on one-way routes?

    Directory of Open Access Journals (Sweden)

    Angelo Antônio Agostinho

    Full Text Available Fish ladders are generally conceived to reestablish connectivity among critical habitats for migratory species, thus mitigating the impacts of the blockage of migration routes by dams. If this management tool is to be meaningful for conserving fish species, it must provide a fully permeable connection and assure both upward and downward movements. However, because reservoirs have very different hydrodynamics than the original river, it is expected that, at least in the inner area, they may constitute an additional barrier to this movement, especially for descending fish. Thus, the present study sought to determine if migratory fish and their offspring disperse downstream from the dam after ascending a ladder and spawning in the upper reaches of a basin. To achieve this purpose, we evaluated the limitation imposed by lentic areas to the descent of eggs, larvae and adults of migratory species; we also determined the abundance and composition of larvae present in the plankton near the dam, and compared the intensity of the upward and downward movements of adult fish. Samples of ichthyoplankton were taken upriver, inside the reservoir, in the river downstream from the dam, and in the forebay of the Lajeado Dam on the Tocantins River (Luis Eduardo Magalhães Hydroelectric Plant, from October, 1999 through September, 2004. The densities of fish ascending and descending the ladder were determined experimentally on eight occasions, from June, 2004 to March, 2005. Due to difficulties in identifying the true fish origin (up or down in the environments connected by the fish passage system, the evaluation of the distribution of migratory fish in reservoirs was based on the landings of the commercial fishery conducted along the Itaipu Reservoir during the four years preceding (2001 through 2003 the construction of the lateral channel (fish-passage mechanism. Fish eggs and larvae drifting down the Tocantins River did not appear in samples taken in the lower

  11. Floodplain farm fields provide novel rearing habitat for Chinook salmon.

    Directory of Open Access Journals (Sweden)

    Jacob V E Katz

    Full Text Available When inundated by floodwaters, river floodplains provide critical habitat for many species of fish and wildlife, but many river valleys have been extensively leveed and floodplain wetlands drained for flood control and agriculture. In the Central Valley of California, USA, where less than 5% of floodplain wetland habitats remain, a critical conservation question is how can farmland occupying the historical floodplains be better managed to improve benefits for native fish and wildlife. In this study fields on the Sacramento River floodplain were intentionally flooded after the autumn rice harvest to determine if they could provide shallow-water rearing habitat for Sacramento River fall-run Chinook salmon (Oncorhynchus tshawytscha. Approximately 10,000 juvenile fish (ca. 48 mm, 1.1 g were reared on two hectares for six weeks (Feb-March between the fall harvest and spring planting. A subsample of the fish were uniquely tagged to allow tracking of individual growth rates (average 0.76 mm/day which were among the highest recorded in fresh water in California. Zooplankton sampled from the water column of the fields were compared to fish stomach contents. The primary prey was zooplankton in the order Cladocera, commonly called water fleas. The compatibility, on the same farm fields, of summer crop production and native fish habitat during winter demonstrates that land management combining agriculture with conservation ecology may benefit recovery of native fish species, such as endangered Chinook salmon.

  12. A history of fish vaccination: science-based disease prevention in aquaculture.

    Science.gov (United States)

    Gudding, Roar; Van Muiswinkel, Willem B

    2013-12-01

    Disease prevention and control are crucial in order to maintain a sustainable aquaculture, both economically and environmentally. Prophylactic measures based on stimulation of the immune system of the fish have been an effective measure for achieving this goal. Immunoprophylaxis has become an important part in the successful development of the fish-farming industry. The first vaccine for aquaculture, a vaccine for prevention of yersiniosis in salmonid fish, was licensed in USA in 1976. Since then the use of vaccines has expanded to new countries and new species simultaneous with the growth of the aquaculture industry. This paper gives an overview of the achievements in fish vaccinology with particular emphasis on immunoprophylaxis as a practical tool for a successful development of bioproduction of aquatic animals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Effect of exposure on salmon lice Lepeophtheirus salmonis population dynamics in Faroese salmon farms

    DEFF Research Database (Denmark)

    Patursson, Esbern J.; Simonsen, Knud; Visser, Andre

    2017-01-01

    We assessed variations in salmon lice Lepeophtheirus salmonis population dynamics in Faroese salmon farms in relationship to their physical exposure to local circulation patterns and flushing with adjacent waters. Factors used in this study to quantify physical exposure are estimates...... of the freshwater exchange rate, the tidal exchange rate and dispersion by tidal currents. Salmon farms were ranked according to the rate of increase in the average numbers of salmon lice per fish. In a multiple linear regression, physical exposure together with temperature were shown to have a significant effect...... threshold of salmon stocking numbers for outbreaks of infection. The study presents a simple method of characterizing salmon farming fjords in terms of their different exposure levels and how they relate to potential self-infection at these sites...

  14. Organotin intake through fish consumption in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Airaksinen, Riikka, E-mail: Riikka.Airaksinen@thl.fi [National Institute for Health and Welfare, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio (Finland); Rantakokko, Panu; Turunen, Anu W.; Vartiainen, Terttu [National Institute for Health and Welfare, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio (Finland); Vuorinen, Pekka J.; Lappalainen, Antti; Vihervuori, Aune [Finnish Game and Fisheries Research Institute, Helsinki (Finland); Mannio, Jaakko [Finnish Environment Institute, Helsinki (Finland); Hallikainen, Anja [Finnish Food Safety Authority Evira, Helsinki (Finland)

    2010-08-15

    Background: Organotin compounds (OTCs) are a large class of synthetic chemicals with widely varying properties. Due to their potential adverse health effects, their use has been restricted in many countries. Humans are exposed to OTCs mostly through fish consumption. Objectives: The aim of this study was to describe OTC exposure through fish consumption and to assess the associated potential health risks in a Finnish population. Methods: An extensive sampling of Finnish domestic fish was carried out in the Baltic Sea and freshwater areas in 2005-2007. In addition, samples of imported seafood were collected in 2008. The chemical analysis was performed in an accredited testing laboratory during 2005-2008. Average daily intake of the sum of dibutyltin (DBT), tributyltin (TBT), triphenyltin (TPhT) and dioctyltin (DOT) ({Sigma}OTCs) for the Finnish population was calculated on the basis of the measured concentrations and fish consumption rates. Results: The average daily intake of {Sigma}OTCs through fish consumption was 3.2 ng/kg bw day{sup -1}, which is 1.3% from the Tolerable Daily Intake (TDI) of 250 ng/kg bw day{sup -1} set by the European Food Safety Authority. In total, domestic wild fish accounted for 61% of the {Sigma}OTC intake, while the intake through domestic farmed fish was 4.0% and the intake through imported fish was 35%. The most important species were domestic perch and imported salmon and rainbow trout. Conclusions: The Finnish consumers are not likely to exceed the threshold level for adverse health effects due to OTC intake through fish consumption.

  15. Organotin intake through fish consumption in Finland

    International Nuclear Information System (INIS)

    Airaksinen, Riikka; Rantakokko, Panu; Turunen, Anu W.; Vartiainen, Terttu; Vuorinen, Pekka J.; Lappalainen, Antti; Vihervuori, Aune; Mannio, Jaakko; Hallikainen, Anja

    2010-01-01

    Background: Organotin compounds (OTCs) are a large class of synthetic chemicals with widely varying properties. Due to their potential adverse health effects, their use has been restricted in many countries. Humans are exposed to OTCs mostly through fish consumption. Objectives: The aim of this study was to describe OTC exposure through fish consumption and to assess the associated potential health risks in a Finnish population. Methods: An extensive sampling of Finnish domestic fish was carried out in the Baltic Sea and freshwater areas in 2005-2007. In addition, samples of imported seafood were collected in 2008. The chemical analysis was performed in an accredited testing laboratory during 2005-2008. Average daily intake of the sum of dibutyltin (DBT), tributyltin (TBT), triphenyltin (TPhT) and dioctyltin (DOT) (ΣOTCs) for the Finnish population was calculated on the basis of the measured concentrations and fish consumption rates. Results: The average daily intake of ΣOTCs through fish consumption was 3.2 ng/kg bw day -1 , which is 1.3% from the Tolerable Daily Intake (TDI) of 250 ng/kg bw day -1 set by the European Food Safety Authority. In total, domestic wild fish accounted for 61% of the ΣOTC intake, while the intake through domestic farmed fish was 4.0% and the intake through imported fish was 35%. The most important species were domestic perch and imported salmon and rainbow trout. Conclusions: The Finnish consumers are not likely to exceed the threshold level for adverse health effects due to OTC intake through fish consumption.

  16. First record of Tuxophorus caligodes (Siphonostomatoida, Tuxophoridae) in sea-farmed cobia, Rachycentron canadum, in Brazil.

    Science.gov (United States)

    da Silva, Ana Carolina; de Moraes, Julieta Rodini Engrácia; Antonucci, Antonio Mataresio; Shimada, Marina Tie; Takemoto, Ricardo Massato; Engrácia Filho, Jair Rodini; de Moraes, Flávio Ruas

    2012-01-01

    The cobia is the only representative of the Rachycentridae family and, because of its zootechnical qualities, production of this fish has been implemented in several countries, such as the United States, Mexico and Brazil. Tuxophorus caligodes is a widespread parasite of marine fish worldwide. For the present report, 15 juvenile cobias were collected from net cages on a fish farm in Ilhabela, state of São Paulo, Brazil, in the winter of 2011. The fish were sacrificed by means of cerebral concussion, and then weighed (280 ± 70.5 g) and measured (27 ± 1.97 cm). After external examination under a stereomicroscope, ectoparasites present on the body surface were collected, fixed and processed for identification. Out of the 15 fish examined, two were parasitized with Tuxophorus caligodes, thus indicating a prevalence of 13.3%. This is the first report of Tuxophorus caligodes in cobias in Brazil.

  17. Study on offshore wind farm wakes based on Envisat ASAR, Radarsat-2 and Sentinel-1

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Badger, Jake

    energy production in clustered wind farms. Envisat ASAR, Radarsat-2 and Sentinel-1 are used in the study covering wind farms in the North Sea and Kattegat Strait. Three types of analysis are performed. The first is a case based on a Radarsat-2 Scan-SAR wide VV scene (30th April 2013 at 17:41 UTC...... is rotation of the data such that all scenes are aligned with inflow and downstream (wake region) based on the wind direction in the wind field maps. The rotation is done at 1 degree intervals. The data from rotated circles (not geo-collocated) are normalized with the winds at the side-lobes. Side......-lobes are regions expected to be undisturbed by the wind farm wake. The key result of the analysis is the significant wind wake deficit at the inner circle, decreasing at outer circles, as expected. The SAR-based results strongly support the wake model results based on PARK and WRF (Hasager et al. 2015b). The third...

  18. Use of soybean meal and papain to partially replace animal protein for culturing three marine fish species: Fish growth and water quality.

    Science.gov (United States)

    Mo, W Y; Lau, R S S; Kwok, A C K; Wong, M H

    2016-12-01

    The main aim of this study was to investigate the feasibility of using soybean meal added with papain to replace half of the fishmeal used in the moist pellets (49% fishmeal and 45% trash fish) developed by the Hong Kong Agriculture, Fisheries and Conservation Department (AFCD) for culturing marine fish. Gold-lined seabream (Rhabdosargus sarba), brown spotted grouper (Epinephelus bleekeri) and pompano (Trachinotus blochii) were farmed at one of the research stations (Kat-O) of AFCD, for a period of 340 days. Results indicated that diets containing papain resulted in better fish growth (reflected by relative weight gain and feed conversion ratio) than diets without papain. In general, wet weight gain of fish depends on the amount of papain added in diet rather than the diet composition. Soybean used in conjunction with papain also contributed to a more effective growth than fish fed with the moist pellets alone. A laboratory experiment (using tanks) was conducted to study the effects of the diets on concentrations of ammonia, nitrite and nitrate in the tank water. Results showed that concentrations of ammonia and nitrate were significantly lower (p marine fish and lower the adverse impact of trash fish and fishmeal on water quality of the mariculture zones. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Feasibility study for evaluating cumulative exposure of downstream migrant juvenile salmonids to total dissolved gas. Final report

    International Nuclear Information System (INIS)

    Abernethy, C.S.; Dauble, D.D.; Johnson, R.L.

    1997-11-01

    A feasibility study was initiated to determine if downstream migrant salmonids could be monitored to determine potential relationships between total dissolved gas (TDG) exposure and signs of gas bubble trauma (GBT). The primary objectives were to: (1) establish logistical requirements for in-river monitoring of TDG exposure, including net pen design, deployment, and navigation constraints; (2) resolve uncertainties associated with effects of the net pen on fish behavior; (3) test the accuracy and precision of in-river monitoring equipment used to measure fish distribution and water quality; and (4) determine the application of hydrologic/flow models to predictions of TDG exposure. In-river measurements included water velocity, boat position, and selected water quality parameters (temperature, dissolved oxygen, pH, depth, conductivity). Fish distribution within the net pen was monitored using scanning sonar, and a split-beam echo sounder was used to evaluate vertical distribution of fish m in the river adjacent to the net pen. Three test drifts were conducted from late July through late August. The studies demonstrated that it was feasible to assemble and deploy a large net pen for mobile monitoring of TDG exposure. Accurate monitoring of vertical and lateral distribution of smolts was performed, and diel differences in behavior were documented. Further, the fish sounded in response to researcher activity on the perimeter platform. Thus, in-transit monitoring for GBT or mortality would affect fish depth distribution and exposure to TDG. Principal recommendations for future studies are directed at improving maneuverability of the net pen in adverse weather conditions and applying new acoustics technology to simultaneously collect fish distribution data from within and outside of the pen. 6 refs., 17 figs., 2 tabs

  20. OVER-EXPRESSION OF GENE ENCODING FATTY ACID METABOLIC ENZYMES IN FISH

    Directory of Open Access Journals (Sweden)

    Alimuddin Alimuddin

    2008-12-01

    Full Text Available Eicosapentaenoic acid (EPA, 20:5n-3 and docosahexaenoic acid (DHA, 22:6n-3 have important nutritional benefits in humans. EPA and DHA are mainly derived from fish, but the decline in the stocks of major marine capture fishes could result in these fatty acids being consumed less. Farmed fish could serve as promising sources of EPA and DHA, but they need these fatty acids in their diets. Generation of fish strains that are capable of synthesizing enough amounts of EPA/DHA from the conversion of α-linolenic acid (LNA, 18:3n-3 rich oils can supply a new EPA/DHA source. This may be achieved by over-expression of genes encoding enzymes involved in HUFA biosynthesis. In aquaculture, the successful of this technique would open the possibility to reduce the enrichment of live food with fish oils for marine fish larvae, and to completely substitute fish oils with plant oils without reducing the quality of flesh in terms of EPA and DHA contents. Here, three genes, i.e. Δ6-desaturase-like (OmΔ6FAD, Δ5-desaturase-like (OmΔ5FAD and elongase-like (MELO encoding EPA/DHA metabolic enzymes derived from masu salmon (Oncorhynchus masou were individually transferred into zebrafish (Danio rerio as a model to increase its ability for synthesizing EPA and DHA. Fatty acid analysis showed that EPA content in whole body of the second transgenic fish generation over-expressing OmΔ6FAD gene was 1.4 fold and that of DHA was 2.1 fold higher (P<0.05 than those in non-transgenic fish. The EPA content in whole body of transgenic fish over-expressing OmΔ5FAD gene was 1.21-fold, and that of DHA was 1.24-fold higher (P<0.05 than those in nontransgenic fish. The same patterns were obtained in transgenic fish over-expressing MELO gene. EPA content was increased by 1.30-fold and DHA content by 1.33-fold higher (P<0.05 than those in non-transgenic fish. The results of studies demonstrated that fatty acid content of fish can be enhanced by over