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Statistical aspects of fish stock assessment  

DEFF Research Database (Denmark)

Fish stock assessments are conducted for two main purposes: 1) To estimate past and present fish abundances and their commercial exploitation rates. 2) To predict the consequences of different management strategies in order to ensure a sustainable fishery in the future. This thesis concerns statistical aspects of fish stocks assessment, which includes topics such as time series analysis, generalized additive models (GAMs), and non-linear state-space/mixed models capable of handling missing data and a high number of latent states and parameters. The aim is to improve the existing methods for stock assessment by application of state-of-the-art statistical methodology. The main contributions are presented in the form of six research papers. The major part of the thesis deals with age-structured assessment models, which is the most common approach. Conversion from length to age distributions in the catches is a necessary step in age-based stock assessment models. For this purpose, GAMs and continuation ratio logits are combined to model the probability of age as a smooth function of length and spatial coordinates, which constitutes an improvement over traditional methods based on area-stratification. GAMs and delta-distributions are applied for the calculation of indices of abundance from trawl survey data, and different error structures for these are investigated. Two extensions to the state-space approach to age-structured stock assessment modelling are presented. The first extension introduces multivariate error distributions on survey catch-at-age data. The second extension is an integrated assessment model for overlapping sub-stocks subject to joint exploitation in the area of overlap. Estimation and inference is carried out using maximum likelihood. Finally, a biomass dynamic model based on stochastic differential equations is presented. This work extends the classical approaches to biomass modelling by incorporating observation errors on the catches, and allowing for missing and non-equidistant samples in time.

Berg, Casper Willestofte

2013-01-01

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Annual trends in catchability and fish stock assessments  

DEFF Research Database (Denmark)

A key assumption of many fish stock assessment models is that catchability is constant over time. We assume here that trends in catchability may occur through fishing power creeping. The tuning fleets, which are prone to fishing power development, may be identified using the "Hybrid" method. A range of catchability trends, including values derived from the "Hybrid" method, is then implemented to standardise the fishing effort of some tuning fleets used in the stock assessments performed by XSA (eXtended Survivors Analysis). Stocks being assessed are the North Sea cod, saithe, plaice and sole. The performances of the new and traditional XSA assessments are compared using criteria based on the precision of catchability estimates, stationarity of Log-catchability residuals and retrospective patterns relative to fishing mortality, spawning stock biomass and recruitment estimates. The performances of the North Sea cod, plaice and sole assessments could be enhanced by accounting for an overall annual increase in the catchability of some of the tuning fleets. No significant trends could be detected in the catchability of the tuning fleets relative to the assessment of the North Sea saithe. By contrast with the traditional assessment, the spawning biomass of cod is expected not to have increased between 1997 and 1998, while the fishing mortality of sole is expected to have increased over the same period.

Ulrich, Clara

2003-01-01

3

FishFrame : Fisheries and stock assessment data framework  

DEFF Research Database (Denmark)

Many research and advisory tasks needs quality assured data on a disaggregated level to make the re-stratification needed to answer a specific question. It is a slow process to gather international datasets for these analyses, because the raw data are spread between labs. Even when gathering data for fixed reoccurring tasks like assessment working groups, data are often late and the quality can be unsatisfactory. The current situation of this “semi-manual distributed datawarehouse” can be improved technically. Methods for quality control, raising and calculation can be discussed and unified. Development and test of software modules can be done once and reused by all. The biggest challenge in this is not technical – it is in organisation, coordination and trust. This challenge has been addressed by FishFrame - a web-based datawarehouse application. The “bottom-up” approach with maximum involvement of end users from as many labs and user groups as possible has been rather slow but quite successful in building international trust and cooperation around the system. This is mandatory prerequisites when our primary goal is not the programming project itself, but the creation of a tool that adds real value to users and in the end improves the way we work with our data. FishFrame version 4.2 is presented and the lessons learned from the process are discussed.

Degel, Henrik; Jansen, Teunis

2006-01-01

4

FISH STOCK ASSESSMENT USING MARINE ACOUSTICS DETECTION AND OCEANOGRAPHICAL CHARACTERISTICS IN JAVA SEA  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Study on the movements of pelagic fish as a benchmark of pelagic fish stock assessments were investigated by using marine acoustics detection and oceanographical characteristics. Several surveys during 1992 to1994 using a dual-beam BioSonics 120 kHz echo-sounder installed on R/V Bawal Putih (192 GT) [...] were carried out in the middle part of Java Sea. The objective was to verify the importance of seasonal shifting on fish abundance under strong influence of environmental changes. Data were systematically stored using Ines-Movies acquisition and processing system along isobaths 50m to100m. A depth layer was adjusted under 10m stratifications. Descriptions on environmental frame were done through measurements of temperature and salinity by using Seabirds CTD profiler. The result shows higher saline water above 34 ppm is stronger influenced on the east and central of Java Sea during south-east monsoon (September to October 1992 and 1993). This condition is strongly related to the occurrence of higher fish density. The vertical and horizontal distribution of fish density shows that several group of fish populations seasonally occupied in the area. These observations clarified that coldwater intrusion from the Flores Sea and Makassar Strait play an important role in the west-eastward movements of Java Sea pelagic fish stocks

Bonar P., Pasaribu; Djisman, Manurung; Duto, Nugroho.

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FISH STOCK ASSESSMENT USING MARINE ACOUSTICS DETECTION AND OCEANOGRAPHICAL CHARACTERISTICS IN JAVA SEA  

Directory of Open Access Journals (Sweden)

Full Text Available Study on the movements of pelagic fish as a benchmark of pelagic fish stock assessments were investigated by using marine acoustics detection and oceanographical characteristics. Several surveys during 1992 to1994 using a dual-beam BioSonics 120 kHz echo-sounder installed on R/V Bawal Putih (192 GT were carried out in the middle part of Java Sea. The objective was to verify the importance of seasonal shifting on fish abundance under strong influence of environmental changes. Data were systematically stored using Ines-Movies acquisition and processing system along isobaths 50m to100m. A depth layer was adjusted under 10m stratifications. Descriptions on environmental frame were done through measurements of temperature and salinity by using Seabirds CTD profiler. The result shows higher saline water above 34 ppm is stronger influenced on the east and central of Java Sea during south-east monsoon (September to October 1992 and 1993. This condition is strongly related to the occurrence of higher fish density. The vertical and horizontal distribution of fish density shows that several group of fish populations seasonally occupied in the area. These observations clarified that coldwater intrusion from the Flores Sea and Makassar Strait play an important role in the west-eastward movements of Java Sea pelagic fish stocks

Bonar P. Pasaribu

2004-01-01

6

Statistical modelling of fish stocks  

DEFF Research Database (Denmark)

In this thesis uncertainty associated with stock assessment has been considered, especially uncertainty associated with the input data to the model. The thesis provides new approaches to analyse the sources of variation in the input data and their magnitude, and an alternative approach for modelling the dynamics of a fish population is suggested. A new approach is introduced to analyse the sources of variation in age composition data, which is one of the most important sources of information in the cohort based models for estimation of stock abundancies and mortalities. The approach combines the continuation-ratio logits, which can take the ordinal and multinomial characteristics of the response into account, and the generalized linear mixed models, which allow for fixed as well as random effects to be analysed. Catch at age data and the associated uncertainties have been estimated, by separating the statistical analysis into separate analyses of the various data sources. The results were combined into estimates of the catch at age data and the associated uncertainties for the sandeel landings from the North Sea in 1989 and 1991. An overview of age-structured stock assessment models is given and it is argued that an approach utilising stochastic differential equations might be advantagous in fish stoch assessments.

Kvist, Trine

1999-01-01

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Implementing ecosystem-based fisheries management: from single-species to integrated ecosystem assessment and advice for Baltic Sea fish stocks  

DEFF Research Database (Denmark)

Theory behind ecosystem-based management (EBM) and ecosystem-based fisheries management (EBFM) is nowwell developed. However, the implementation of EBFM exemplified by fisheries management in Europe is still largely based on single-species assessments and ignores the wider ecosystem context and impact. The reason for the lack or slow implementation of EBM and specifically EBFM is a lack of a coherent strategy. Such a strategy is offered by recently developed integrated ecosystemassessments (IEAs), a formal synthesis tool to quantitatively analyse information on relevant natural and socio-economic factors, in relation to specified management objectives. Here, we focus on implementing the IEA approach for Baltic Sea fish stocks. We combine both tactical and strategic management aspects into a single strategy that supports the present Baltic Sea fish stock advice, conducted by the International Council for the Exploration of the Sea (ICES). We first review the state of the art in the development of IEA within the current management framework. We then outline and discuss an approach that integrates fish stock advice and IEAs for the Baltic Sea. We intentionally focus on the central Baltic Sea and its three major fish stocks cod (Gadus morhua), herring (Clupea harengus), and sprat (Sprattus sprattus), but emphasize that our approach may be applied to other parts and stocks of the Baltic, as well as other ocean areas

Möllmann, Christian; Lindegren, Martin

2014-01-01

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The alarming decline of Mediterranean fish stocks.  

Science.gov (United States)

In recent years, fisheries management has succeeded in stabilizing and even improving the state of many global fisheries resources [1-5]. This is particularly evident in areas where stocks are exploited in compliance with scientific advice and strong institutional structures are in place [1, 5]. In Europe, the well-managed northeast (NE) Atlantic fish stocks have been recovering in response to decreasing fishing pressure over the past decade [3-6], albeit with a long way to go for a universal stock rebuild [3, 7]. Meanwhile, little is known about the temporal development of the European Mediterranean stocks, whose management relies on input controls that are often poorly enforced. Here, we perform a meta-analysis of 42 European Mediterranean stocks of nine species in 1990-2010, showing that exploitation rate has been steadily increasing, selectivity (proportional exploitation of juveniles) has been deteriorating, and stocks have been shrinking. We implement species-specific simulation models to quantify changes in exploitation rate and selectivity that would maximize long-term yields and halt stock depletion. We show that stocks would be more resilient to fishing and produce higher long-term yields if harvested a few years after maturation because current selectivity is far from optimal, especially for demersal stocks. The European Common Fisheries Policy that has assisted in improving the state of NE Atlantic fish stocks in the past 10 years has failed to deliver similar results for Mediterranean stocks managed under the same policy. Limiting juvenile exploitation, advancing management plans, and strengthening compliance, control, and enforcement could promote fisheries sustainability in the Mediterranean. PMID:25017210

Vasilakopoulos, Paraskevas; Maravelias, Christos D; Tserpes, George

2014-07-21

9

Fish stocking density impacts tank hydrodynamics  

DEFF Research Database (Denmark)

The effect of stocking density upon the hydrodynamics of a circular tank, configured in a recirculation system, was investigated. Red drums Sciaenops ocellatus of approximately 140 g wet weight, were stocked at five rates varying from 0 to 12 kg m-3. The impact of the presence of fish upon tank hydrodynamics was established using in-tank-based Rhodamine WT fluorometry at a flow rate of 0.23 l s-1 (tank exchange rate of 1.9 h-1). With increasing numbers of animals, curvilinear relationships were observed for dispersion coefficients and tank mixing times. Stocking densities of 3, 6, 9 and 12 kg m-3 resulted in a 0.2-, 0.5-, 2.4-, and 3.2-fold decrease in mixing time relative to that observed for empty tanks (Pb0.001). Udgivelsesdato: APR 28

Rasmussen, Michael R.; Lunger, Angela

2006-01-01

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Fish stock assessment of piraputanga Brycon microlepis in the Cuiabá River Basin, Pantanal of Mato Grosso, Brazil.  

Science.gov (United States)

Fork length measurements of individuals of Brycon microlepis landed and commercialized at the Porto Market in Cuiabá, MT, from May-October 1996 to May-October 1997 were used to estimate growth and mortality parameters for this species. The average estimated populational parameters were: L infinity = 705 mm, k = 0.275 year-1, C = 0.775, WP = 0.465, Lc = 164 mm, M = 0.585 year-1, Z = 0.822 year-1, with F = 0.237 year-1. Yield per recruit analysis suggests that the stock is not yet overexploited. PMID:12185916

Mateus, L A de F; Estupiñán, G M B

2002-02-01

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Integrating genetic and parasitological approaches in the frame of multidisciplinary fish stock analysis.  

Science.gov (United States)

To assess fish stocks boundaries and state, the tools of population genetics have been widely used, contributing to the evaluation of relevant parameters such as the identification of stock boundaries, the assessment of gene flow and the estimation of effective population size. Also, increasing evidences show that the monitoring of the genetic diversity level is a reliable method to check the status of fish stocks. However, genetics cannot answer all the questions. For example, in high gene flow species the genetic approach could have not enough resolution to identify stock limits, while the use of parasites as biological tags could provide insights into stock structure. Even better, the so-called holistic approach, applying simultaneously a wide range of complementary techniques, is the only one considered able to provide a reliable and complete picture of fish stocks and to address a sustainable exploitation of marine resources. The work will present some examples from multidisciplinary studies concerning commercially relevant species with different biological features: the demersal European hake (Merluccius merluccius), the small pelagic horse mackerel (Trachurus trachurus) and the large pelagic swordfish (Xiphias gladius). In all these case studies merging genetic, parasitological and environmental data helped to reveal the real patterns of stocks structure. PMID:18410069

Cimmaruta, R; Mattiucci, S; Nascetti, G

2007-09-01

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Intelligent Fish Freshness Assessment  

Directory of Open Access Journals (Sweden)

Full Text Available Fish species identification and automated fish freshness assessment play important roles in fishery industry applications. This paper describes a method based on support vector machines (SVMs to improve the performance of fish identification systems. The result is used for the assessment of fish freshness using artificial neural network (ANN. Identification of the fish species involves processing of the images of fish. The most efficient features were extracted and combined with the down-sampled version of the images to create a 1D input vector. Max-Win algorithm applied to the SVM-based classifiers has enhanced the reliability of sorting to 96.46%. The realisation of Cyranose 320 Electronic nose (E-nose, in order to evaluate the fish freshness in real-time, is experimented. Intelligent processing of the sensor patterns involves the use of a dedicated ANN for each species under study. The best estimation of freshness was provided by the most sensitive sensors. Data was collected from four selected species of fishes over a period of ten days. It was concluded that the performance can be increased using individual trained ANN for each specie. The proposed system has been successful in identifying the number of days after catching the fish with an accuracy of up to 91%.

Deena Benjamin

2008-04-01

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On the interplay of environmental changes and fishing pressure in exploited fish stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fish in many exploited stocks grow faster and mature earlier at either larger or smaller sizes in comparisonto pre-exploitation periods. These changes can be driven by both genetic and phenotypic responses.At the same time, these stocks may adjust to other changes of the environment such as increasing/decreasing overall productivity or changes in temperature. Using a model of planktivorous fish withannual spawning and size- and density-dependent individual growth, we ask if the interplay of e...

Boukal, David S.; Roos, Andre M.; Persson, Lennart; Heino, Mikko

2010-01-01

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Rebuilding EU fish stocks and fisheries, a process under way?  

DEFF Research Database (Denmark)

As a signatory to the World Summit on Sustainable Development (WSSD), the European Union (EU) has made a commitment to maintain or restore fish stocks to levels that can produce the maximum sustainable yield (MSY), and where possible not later than 2015. So how has the EU's Common Fisheries Policy (CFP) fared in trying to achieve this objective? The development of the status of 41 commercially exploited fish stocks from the North East Atlantic, North Sea and Baltic Sea (FAO Area 27) was analysed together with the economic performance of the fleets exploiting those stocks. The analyses indicate that the exploitation status for many of the stocks has greatly improved during the last 10 years while the economic performance of the fleets over the same period has been highly variable. The main economic indicators (gross value added (GVA) and operating cash flow (OCF)) have gradually improved at a time when the general economic situation, which has a great influence on the markets, costs and purchase power, has worsened. While recognizing that much remains to be done to achieve the objective of the WSSD, the analyses indicate that actions implemented in the last decade under the CFP have led to an improvement in the status of many commercially important fish stocks and their fleets towards levels that are closer to those producing MSY.

Cardinale, M.; Dörner, H.

2013-01-01

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Fish status survey of Nordic lakes: effects of acidification, eutrophication and stocking activity on present fish species composition.  

Science.gov (United States)

The status of fish populations in 3821 lakes in Norway, Sweden and Finland was assessed in 1995-1997. The survey lakes were chosen by stratified random sampling from all (126 482) Fennoscandian lakes > or = 0.04 km2. The water chemistry of the lakes was analyzed and information on fish status was obtained by a postal inquiry. Fish population losses were most frequent in the most highly acidified region of southern Norway and least common in eastern Fennoscandia. According to the inquiry results, the number of lost stocks of brown trout (Salmo trutta), roach (Rutilus rutilus), Arctic char (Salvelinus alpinus) and perch (Perca fluviatilis) was estimated to exceed 10000. The number of stocks of these species potentially affected by the low alkalinity of lake water was estimated to exceed 11000. About 3300 lakes showed high total phosphorus (> 25 microg L(-1)) and cyprinid dominance in eastern Fennoscandia, notably southwestern Finland. This survey did not reveal any extinction of fish species due to eutrophication. One-third of the lakes had been artificially stocked with at least one new species, most often brown trout, whitefish (Coregonus lavaretus s.l.), Arctic char, rainbow trout (Oncorhynchus mykiss), pike-perch (Stizostedion lucioperca), grayling (Thymallus thymallus), pike (Esox lucius), bream (Abramis brama), tench (Tinca tinca) and European minnow (Phoxinus phoxinus). The number of artificially manipulated stocks of these species in Fennoscandian lakes was estimated to exceed 52000. Hence, the number of fish species occurring in Nordic lakes has recently been changed more by stockings than by losses of fish species through environmental changes such as acidification. PMID:12733793

Tammi, Jouni; Appelberg, Magnus; Beier, Ulrika; Hesthagen, Trygve; Lappalainen, Antti; Rask, Martti

2003-03-01

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Eco-label conveys reliable information on fish stock health to seafood consumers.  

Science.gov (United States)

Concerns over fishing impacts on marine populations and ecosystems have intensified the need to improve ocean management. One increasingly popular market-based instrument for ecological stewardship is the use of certification and eco-labeling programs to highlight sustainable fisheries with low environmental impacts. The Marine Stewardship Council (MSC) is the most prominent of these programs. Despite widespread discussions about the rigor of the MSC standards, no comprehensive analysis of the performance of MSC-certified fish stocks has yet been conducted. We compared status and abundance trends of 45 certified stocks with those of 179 uncertified stocks, finding that 74% of certified fisheries were above biomass levels that would produce maximum sustainable yield, compared with only 44% of uncertified fisheries. On average, the biomass of certified stocks increased by 46% over the past 10 years, whereas uncertified fisheries increased by just 9%. As part of the MSC process, fisheries initially go through a confidential pre-assessment process. When certified fisheries are compared with those that decline to pursue full certification after pre-assessment, certified stocks had much lower mean exploitation rates (67% of the rate producing maximum sustainable yield vs. 92% for those declining to pursue certification), allowing for more sustainable harvesting and in many cases biomass rebuilding. From a consumer's point of view this means that MSC-certified seafood is 3-5 times less likely to be subject to harmful fishing than uncertified seafood. Thus, MSC-certification accurately identifies healthy fish stocks and conveys reliable information on stock status to seafood consumers. PMID:22928029

Gutiérrez, Nicolás L; Valencia, Sarah R; Branch, Trevor A; Agnew, David J; Baum, Julia K; Bianchi, Patricia L; Cornejo-Donoso, Jorge; Costello, Christopher; Defeo, Omar; Essington, Timothy E; Hilborn, Ray; Hoggarth, Daniel D; Larsen, Ashley E; Ninnes, Chris; Sainsbury, Keith; Selden, Rebecca L; Sistla, Seeta; Smith, Anthony D M; Stern-Pirlot, Amanda; Teck, Sarah J; Thorson, James T; Williams, Nicholas E

2012-01-01

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78 FR 66681 - Draft 2013 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...RIN 0648-XC853 Draft 2013 Marine Mammal Stock Assessment Reports AGENCY: National Marine...Atlantic, and Pacific regional marine mammal stock assessment reports (SARs) in accordance...Silver Spring, MD 20910-3226, Attn: Stock Assessments. Instructions: All...

2013-11-06

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76 FR 52940 - Draft 2011 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...RIN 0648-XA595 Draft 2011 Marine Mammal Stock Assessment Reports AGENCY: National Marine...Atlantic, and Pacific regional marine mammal stock assessment reports (SARs) in accordance...Silver Spring, MD 20910-3226, Attn: Stock Assessments. Instructions: All...

2011-08-24

19

77 FR 47043 - Draft 2012 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...RIN 0648-XC062 Draft 2012 Marine Mammal Stock Assessment Reports AGENCY: National Marine...Atlantic, and Pacific regional marine mammal stock assessment reports (SARs) in accordance...Silver Spring, MD 20910-3226, Attn: Stock Assessments. Instructions: All...

2012-08-07

20

A definition of depletion of fish stocks  

Science.gov (United States)

Attention was focused on the need of a common and better understanding of the term depletion as applied to the fisheries in order to eliminate if possible the existing inexactness of thought on the subject. Depletion has been confused at various times with at least ten different ideas associated with it but which, as has has heen pointed out, are not synonymous at all. In defining depletion we must recognize that the term represents a condition and must not he confounded with the cause (overfishing) that leads to this condition or with the symptoms that identify it. Depletion was defined as a reduction, through overfishing, in the level of abundance of the exploitable segment of a stock that prevents the realization of the maximum productive capacity.

Van Oosten, John

1949-01-01

 
 
 
 
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Topmouth gudgeon Pseudorasbora parva: a side effect of fish stocking  

Directory of Open Access Journals (Sweden)

Full Text Available he topmouth gudgeon Pseudorasbora parva is an eastern-Asian cyprinid species, which inrelatively short time has colonised nearly the whole Europe. In some regions it has become a notablereproduction success and significantly disrupted native ecosystems. Such a fast expansion is mostprobably caused by uncontrolled transfers of stocking fish, mainly Asian carps, i.e., Ctenopharyngodonidella, and Hypophthalmichthys spp. The case of P. parva invasion demonstrates the risk oftranslocations of fish, as well as urgent need of more caution and prevention in order to avoid furthersuch unexpected guests.

Micha? Nowak

2009-12-01

22

Duck Valley Resident Fish Stocking Program, 2000 Final Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

The Shoshone-Paiute Tribes fish-stocking program was begun in 1988 and is intended to provide a subsistence fishery for the tribal members. The program stocks catchable and fingerling size trout in Mt. View and Sheep Creek Reservoirs. Rainbow trout are purchased from only certified disease-free facilities to be stocked in our reservoirs. This project will help restore a fishery for tribal members that historically depended on wild salmon and steelhead in the Owyhee and Bruneau Rivers and their tributaries for their culture as well as for subsistence. This project is partial substitution for loss of anadromous fish production due to construction and operation of hydroelectric dams on the Columbia and Snake Rivers. Until anadromous fish can be returned to the Owyhee and Bruneau Rivers this project will continue indefinitely. As part of this project the Shoshone-Paiute Tribes will also receive income in the form of fees from non-tribal members who come to fish these reservoirs. Regular monitoring and evaluation of the fishery will include sampling for length/weight/condition and for signs of disease. A detailed Monitoring and evaluation plan has been put in place for this project. However due to budget limitations on this project only the fishery surveys and limited water quality work can be completed. A creel survey was initiated in 1998 and we are following the monitoring and evaluation schedule for this program (as budget allows) as well as managing the budget and personnel. This program has been very successful in the past decade and has provided enjoyment and sustenance for both tribal and non-tribal members. All biological data and stocking rates will be including in the Annual reports to Bonneville Power Administration (BPA).

Dodson, Guy; Pero, Vincent

2002-01-01

23

Biological reference points for fish stocks in a multispecies context  

DEFF Research Database (Denmark)

Biological reference points (BRPs) are widely used to define safe levels of harvesting for marine fish populations. Most BRPs are either minimum acceptable biomass levels or maximum fishing mortality rates. The values of BRPs are determined from historical abundance data and the life-history parameters of the fish species. However, when the life-history parameters change over time, the BRPs become moving targets. In particular, the natural mortality rate of prey species depends on predator levels; conversely, predator growth rates depend on prey availability. We tested a suite of BRPs for their robustness to observed changes in natural mortality and growth rates. We used the relatively simple Baltic Sea fish community for this sensitivity test, with cod as predator and sprat and herring as prey. In general, the BRPs were much more sensitive to the changes in natural mortality rates than to growth variation. For a prey species like sprat, fishing mortality reference levels should be conditioned on the level ofpredation mortality. For a predator species, a conservative level of fishing mortality can be identified that will prevent growth overfishing and ensure stock replacement. These first- order multispecies interactions should be considered when defining BRPs for medium-term (5-10 year) management decisions.

Gislason, Henrik

2001-01-01

24

Estimation of the parameters of fish stock dynamics from catch-at-age data and indices of abundance:can natural and fishing mortality be separated?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Models for fluctuations in size of fish stocks must include parameters that describe expected dynamics, as well as stochastic influences. In addition, reliable population projections also require assessments about the uncertainties in estimates of vital parameters. Here we develop an age-structured model of population dynamics based on catch-at-age data and indices of abundance in which the natural and fishing mortality are separated in a Bayesian state-space model. Markov chain Monte Carlo m...

Aanes, Sondre; Engen, Steinar; Sæther, Bernt-erik; Aanes, Ronny

2007-01-01

25

The effect of fish impingement at Sizewell 'A' Power Station, Suffolk, on North Sea fish stocks  

International Nuclear Information System (INIS)

Samples collected from the cooling water intake screens of Sizewell 'A' power station over a 12 month period contained 73 species of fish. Of these, only 20 species were present on more than 50% of sampling dates and only 7 commercially exploited species were caught in quantities of more than a few hundred over the year; namely sprat, herring, cod, whiting, sole, dab and plaice. These species formed the basis of analysis of the impact of the Power Station on commercial species. Commercial species found in the Sizewell area are part of major North Sea stocks. The impact of the losses due to the Power Station is spread over these stocks, hence the effect is minimal. The mortality rate caused by the Power Station is one thousandth to one hundred-thousandth, depending on species, of that caused by commercial fishing and the effect is less than that of a small, inefficient commercial trawler. (author)

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Evolutionary regime shifts in age and size at maturation of exploited fish stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Worldwide declines of fish stocks raise concerns about deleterious consequences of harvesting for stock abundances and individual life histories, and call for appropriate recovery strategies. Fishes in exploited stocks mature earlier at either larger or smaller sizes due to both genetic and plastic responses. The latter occur commonly when reduced competition for food leads to faster growth. Using a size-structured consumer–resource model, which accounts for both genetic and plastic respons...

Roos, Andre? M.; Boukal, David S.; Persson, Lennart

2006-01-01

27

75 FR 46912 - Draft 2010 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...RIN 0648-XW72 Draft 2010 Marine Mammal Stock Assessment Reports AGENCY: National Marine...Atlantic, and Pacific regional marine mammal stock assessment reports (SARs) in accordance...Silver Spring, MD 20910-3226, Attn: Stock Assessments. Comments may also be...

2010-08-04

28

Effects of marine protected areas on overfished fishing stocks with multiple stable states.  

Science.gov (United States)

Marine protected areas (MPAs) have attracted much attention as a tool for sustainable fisheries management, restoring depleted fisheries stocks and maintaining ecosystems. However, even with total exclusion of fishing effort, depleted stocks sometimes show little or no recovery over a long time period. Here, using a mathematical model, we show that multiple stable states may hold the key to understanding the tendency for fisheries stocks to recover because of MPAs. We find that MPAs can have either a positive effect or almost no effect on the recovery of depleted fishing stocks, depending on the fish migration patterns and the fishing policies. MPAs also reinforce ecological resilience, particularly for migratory species. In contrast to previous reports, our results show that MPAs have small or sometimes negative effects on the recovery of sedentary species. Unsuitable MPA planning might result in low effectiveness or even deterioration of the existing condition. PMID:24083999

Takashina, Nao; Mougi, Akihiko

2014-01-21

29

Simulation testing the robustness of stock assessment models to error: some results from the ICES strategic initiative on stock assessment methods  

DEFF Research Database (Denmark)

The World Conference on Stock Assessment Methods (July 2013) included a workshop on testing assessment methods through simulations. The exercise was made up of two steps applied to datasets from 14 representative fish stocks from around the world. Step 1 involved applying stock assessments to datasets with varying degrees of effort dedicated to optimizing fit. Step 2 was applied to a subset of the stocks and involved characteristics of given model fits being used to generate pseudo-data with error. These pseudo-data were then provided to assessment modellers and fits to the pseudo-data provided consistency checks within (self-tests) and among (cross-tests) assessment models. Although trends in biomass were often similar across models, the scaling of absolute biomass was not consistent across models. Similar types of models tended to perform similarly (e.g. age based or production models). Self-testing and cross-testing of models are a useful diagnostic approach, and suggested that estimates in the most recent years of time-series were the least robust. Results from the simulation exercise provide a basis for guidance on future large-scale simulation experiments and demonstrate the need for strategic investments in the evaluation and development of stock assessment methods

Deroba, J. J.; Butterworth, D. S.

2014-01-01

30

Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2001 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power Planning Council (NPPC). The NPPC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPPC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area and the Columbia Basin Blocked Area Management Plan (1998). The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of Blocked Area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the Blocked Area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. Common collection and analytical methodologies were developed in 1999. In 1999, 2000, and 2001 the project began addressing some of the identified data gaps throughout the Blocked Area. Data collection of established projects and a variety of newly developed sampling projects are ongoing. Projects developed and undertaken by JSAP fisheries managers include investigations of the Pend Orielle River and its tributaries, the Little Spokane River and its tributaries, and water bodies within and near the Spokane Indian Reservation. Migration patterns of adfluvial and reservoir fish in Box Canyon Reservoir and its tributaries, a baseline assessment of Boundary Reservoir and its tributaries, ecological assessment of mountain lakes in Pend Oreille County, and assessments of seven streams and four lakes on the Spokane Indian Reservation were completed by 2000. Assessments of the Little Spokane River and its tributaries, tributaries to the Pend Oreille River, small lakes in southern Pend Oreille County, and water bodies within and near the Spokane Indian Reservation were conducted in 2001. This work was done in accordance with the scope of work approved by Bonneville Power Administration (BPA).

Connor, Jason M. (Kalispell Department of Natural Resources, Usk, WA); McLellan, Jason G. (Washington Department of Fish and Wildlife, Spokane, WA); O' Connor, Dick (Washington Department of Fish and Wildlife, Olympia, WA)

2003-01-01

31

Resident Fish Stock above Chief Joseph and Grand Coulee Dams; 2002 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area. The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of Blocked Area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the Blocked Area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. Common collection and analytical methodologies were developed in 1999. In 1999, 2000, and 2001 the project began addressing some of the identified data gaps throughout the Blocked Area. Data collection of established projects and a variety of newly developed sampling projects are ongoing. Projects developed and undertaken by JSAP fisheries managers include investigations of the Pend Orielle River and its tributaries, the Little Spokane River and its tributaries, and water bodies within and near the Spokane Indian Reservation. Migration patterns of adfluvial and reservoir fish in Box Canyon Reservoir and its tributaries, a baseline assessment of Boundary Reservoir and its tributaries, ecological assessment of mountain lakes in Pend Oreille County, and assessments of streams and lakes on the Spokane Indian Reservation were completed by 2001. Assessments of the Little Spokane River and its tributaries, tributaries to the Pend Oreille River, small lakes in Pend Oreille County, WA, and water bodies within and near the Spokane Indian Reservation were conducted in 2002. This work was done in accordance with the scope of work approved by Bonneville Power Administration (BPA).

Connor, Jason M. (Kalispel Department of Natural Resources, Usk, WA); McLellan, Jason G. (Washington Department of Fish and Wildlife, Spokane, WA); Butler, Chris (Spokane Tribe of Indians, Department of Natural Resources, Wellpinit, WA)

2003-09-01

32

Fish stocking density induced growth responses of some biogeochemical cycling bacterial population  

Directory of Open Access Journals (Sweden)

Full Text Available Experiment was performed to ascertain the effect of fish stocking density on population growth performance of some biogeochemical cycling bacteria in carp culture system. Advanced fry of Catla catla L., Labeo bata Ham. and Cyprinus carpio L. were introduced into tanks @ 8, 13, 16 and 32 fry tank-1 maintaining the ratio of C. catla -2 : L. bata -3 : C. carpio -3. Each tank was fertilized with mixed fertilizer @ 200 g week-1 during the rearing period of 150 days. Water samples were collected for examination of bacterial population, primary productivity and water quality parameters at weekly and biweekly intervals. Growth of fish was recorded at regular intervals. Statistical analysis of collected data was done by ANOVA and LSD for separation of mean (P < 0.05. Bacterial growth rate and productivity tended to rise with increasing stocking density showing maximum at stocking density 32 fry tank-1 whereas, fish growth exhibited an increasing trend upto stocking density 16 fry tank-1 and declined in further increment of fish density. Stocking density dependent growth efficiency of different bacteria (heterotrophic bacteria, cellulose decomposing bacteria, denitrifying bacteria and phosphate solubilizing bacteria varied from 18 to 62.7%, 45 to 140%, 61 to 238% and 79 to 382% in stocking density 8, 13, 16 and 32 fry tank-1 , respectively. Results clearly revealed that higher stocking density of fishes liberates higher quantity of faecal matter containing proportionately greater amount of nutrients having more scope for bacteria to act upon the faecal matter resulting in higher bacterial population and productivity in one hand and fish growth inhibition due to stressful and uncongenial environmental condition developed by means of heavy nutrient load on the other hand. Therefore, it may be concluded that stocking density influencing the growth of biogeochemical cycling bacterial population in fish culture system.

J. N. Bhakta

2010-02-01

33

Examining the 10-Year Rebuilding Dilemma for U.S. Fish Stocks  

Science.gov (United States)

Worldwide, fishery managers strive to maintain fish stocks at or above levels that produce maximum sustainable yields, and to rebuild overexploited stocks that can no longer support such yields. In the United States, rebuilding overexploited stocks is a contentious issue, where most stocks are mandated to rebuild in as short a time as possible, and in a time period not to exceed 10 years. Opponents of such mandates and related guidance argue that rebuilding requirements are arbitrary, and create discontinuities in the time and fishing effort allowed for stocks to rebuild due to differences in productivity. Proponents, however, highlight how these mandates and guidance were needed to curtail the continued overexploitation of these stocks by setting firm deadlines on rebuilding. Here we evaluate the statements made by opponents and proponents of the 10-year rebuilding mandate and related guidance to determine whether such points are technically accurate using a simple population dynamics model and a database of U.S. fish stocks to parameterize the model. We also offer solutions to many of the issues surrounding this mandate and its implementation by recommending some fishing mortality based frameworks, which meet the intent of the 10-year rebuilding requirement while also providing more flexibility. PMID:25375788

Patrick, Wesley S.; Cope, Jason

2014-01-01

34

Resident Fish Stock above Chief Joseph and Grand Coulee Dams; 2003-2004 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial and native fish assemblages in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area. The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of Blocked Area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the Blocked Area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. Common collection and analytical methodologies were developed in 1999. The project began addressing identified data gaps throughout the Blocked Area in 1999. Data collection of established projects and a variety of newly developed sampling projects are ongoing. Projects developed and undertaken by JSAP fisheries managers include investigations of the Pend Orielle River and its tributaries, the Little Spokane River and its tributaries, and water bodies within and near the Spokane Indian Reservation. Migration patterns of adfluvial and reservoir fish in Box Canyon Reservoir and its tributaries, a baseline assessment of Boundary Reservoir and its tributaries, ecological assessment of mountain lakes in Pend Oreille County, and assessments of streams and lakes on the Spokane Indian Reservation were completed by 2001. Assessments of the Little Spokane River and its tributaries, Spokane River below Spokane Falls, tributaries to the Pend Oreille River, small lakes in Pend Oreille County, WA, and water bodies within and near the Spokane Indian Reservation were conducted in 2002 and 2003. This work was done in accordance with the scope of work approved by Bonneville Power Administration (BPA).

Connor, Jason M. (Kalispel Tribe of Indians, Usk, WA); McLellan, Jason G. (Washington Department of Fish and Wildlife, Olympia, WA); Butler, Chris (Spokane Tribe of Indians, Wellpinit, WA)

2005-11-01

35

Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2002-2003 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial and native fish assemblages in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area. The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of Blocked Area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the Blocked Area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. Common collection and analytical methodologies were developed in 1999. The project began addressing identified data gaps throughout the Blocked Area in 1999. Data collection of established projects and a variety of newly developed sampling projects are ongoing. Projects developed and undertaken by JSAP fisheries managers include investigations of the Pend Orielle River and its tributaries, the Little Spokane River and its tributaries, and water bodies within and near the Spokane Indian Reservation. Migration patterns of adfluvial and reservoir fish in Box Canyon Reservoir and its tributaries, a baseline assessment of Boundary Reservoir and its tributaries, ecological assessment of mountain lakes in Pend Oreille County, and assessments of streams and lakes on the Spokane Indian Reservation were completed by 2001. Assessments of the Little Spokane River and its tributaries, Spokane River below Spokane Falls, tributaries to the Pend Oreille River, small lakes in Pend Oreille County, WA, and water bodies within and near the Spokane Indian Reservation were conducted in 2002 and 2003. This work was done in accordance with the scope of work approved by Bonneville Power Administration (BPA).

Connor, Jason M. (Kalispel Tribe of Indians, Usk, WA); McLellan, Jason G. (Washington Department of Fish and Wildlife); Butler, Chris (Spokane Tribe of Indians, Wellpinit, WA)

2006-02-01

36

Annual Stock Assessment - CWT [Coded Wire Tag program] (USFWS), Annual Report 2007.  

Energy Technology Data Exchange (ETDEWEB)

In 1989 the Bonneville Power Administration (BPA) began funding the evaluation of production groups of juvenile anadromous fish not being coded-wire tagged for other programs. These groups were the 'Missing Production Groups'. Production fish released by the U.S. Fish and Wildlife Service (FWS) without representative coded-wire tags during the 1980s are indicated as blank spaces on the survival graphs in this report. This program is now referred to as 'Annual Stock Assessment - CWT'. The objectives of the 'Annual Stock Assessment' program are to: (1) estimate the total survival of each production group, (2) estimate the contribution of each production group to fisheries, and (3) prepare an annual report for USFWS hatcheries in the Columbia River basin. Coded-wire tag recovery information will be used to evaluate the relative success of individual brood stocks. This information can also be used by salmon harvest managers to develop plans to allow the harvest of excess hatchery fish while protecting threatened, endangered, or other stocks of concern. All fish release information, including marked/unmarked ratios, is reported to the Pacific States Marine Fisheries Commission (PSMFC). Fish recovered in the various fisheries or at the hatcheries are sampled to recover coded-wire tags. This recovery information is also reported to PSMFC. This report has been prepared annually starting with the report labeled 'Annual Report 1994'. Although the current report has the title 'Annual Report 2007', it was written in fall of 2008 using data available from RMIS that same year, and submitted as final in January 2009. The main objective of the report is to evaluate survival of groups which have been tagged under this ongoing project.

Pastor, Stephen M. [U.S. Fish and Wildlife Service, Columbia River Fisheries Program Office

2009-07-21

37

Forecasting Fish Stock Recruitment and Planning Optimal Harvesting Strategies by Using Neural Network  

Directory of Open Access Journals (Sweden)

Full Text Available Recruitment prediction is a key element for management decisions in many fisheries. A new approach using neural network is developed as a tool to produce a formula for forecasting fish stock recruitment. In order to deal with the local minimum problem in training neural network with back-propagation algorithm and to enhance forecasting precision, neural network’s weights are adjusted by optimization algorithm. It is demonstrated that a well trained artificial neural network reveals an extremely fast convergence and a high degree of accuracy in the prediction of fish stock recruitment.

Lin Sun

2009-11-01

38

Fish Catch Assessment of Maljhee-Kangsa Floodplain in Bangladesh  

Directory of Open Access Journals (Sweden)

Full Text Available A study was conducted to assess fish catch in the Baila beel of Maljhee-Kangsa floodplain in the north-central part of Bangladesh. A total of 7 types of fishing gear were found in use by the fishermen which are: push net, gill net, cast net, lift net, current net, fish traps and hooks. The duration of fishing depends on use of fishing gear, season, habitat type, water depth and abundance of fishes. From the survey it was found that the highest average fishing time was estimated in fish trap (18.04 h/day and the lowest in push net (3.21 h/day. There are variations in the Catch Per Unit of Effort (CPUE of different gears in different seasons. The highest and the lowest CPUE were recorded in current net and hook which were 0.31 and 0.02 kg/gear/h, respectively. According to the fishermen, the highest catch was obtained during the receding of floodwater in post-monsoon season (October-December and the lowest during the pre-monsoon season (April-June. A total of 39 fish species were identified in the catches of different gears. From the survey it was found that a fisherman daily catches an average 1.43 kg of fish. Alarmingly, the catch of fish has declined by an estimated 20% in the past five years. Concerns arise about the sustainable catches due to over fishing and indiscriminate use of gears. It is therefore necessary to provide institutional and organisational supports for artificial stocking and establishing fish sanctuaries through active community participation for sustainable catches.

N. Ahmed

2005-01-01

39

How can a potential oil pollution affect the recruitment to fish stocks?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Eggs, larvae and the larvae's first search for food are the most critical stages in a fish life, both to threats from natural causes and pollution. Based on experimental studies of several species of fish eggs, larvae and zooplankton, and their in situ abundance, calculations of potential reduction of the affected year class or stock are demonstrated. The organisms exposed to oil concentrations likely to be found in the marine environment show considerably variation from species to species. W...

Føyn, Lars; Serigstad, Bjørn

1989-01-01

40

Effects of fish stocking on ecosystem services: an overview and case study using the Stockholm Archipelago.  

Science.gov (United States)

In this article, we focus on documented and possible effects of fish stocking in terms of ecosystem services. The increasing use of fish stocking between 1970 and 2000 in the semiurban setting of Stockholm archipelago, Sweden, is used as case study. The objective is to analyze this management practice from an ecosystem perspective, accounting for both the ecological and social context of releasing fish. The results show that enhancements of four native species (Salmo S. trutta, Salmo salar, Stizostedion lucioperca, and Anguilla anguilla) have dominated over new introductions of one nonnative species. (Oncorhynchus mykiss). The major objective has been to increase fish catches for local resource users. Involved stakeholders include three management agencies, one hydropower company, and several local sport fishing associations. Documented effects focus on recapture and production rates. However, our analysis suggests that additional positive or negative effects on biodiversity, food web dynamics, mobile links, or ecological information may also result, with possible consequences for the long-term provision of food, game, and aesthetic values. We conclude that a more adaptive and cooperative management approach could benefit from a deeper analysis of where, when, and what species is released, by whom, which stakeholders that use the fish and those ecosystem services the fish generate, and of the role of formal and informal institutions for monitoring and evaluating the success of releasing fish. PMID:15156349

Holmlund, Cecilia M; Hammer, Monica

2004-06-01

 
 
 
 
41

Forecasting fish stock dynamics under climate change: Baltic herring (Clupea harengus) as a case study  

DEFF Research Database (Denmark)

Climate change and anthropogenic disturbances may affect marine populations and ecosystems through multiple pathways. In this study we present a framework in which we integrate existing models and knowledge on basic regulatory processes to investigate the potential impact of future scenarios of fisheries exploitation and climate change on the temporal dynamics of the central Baltic herring stock. Alternative scenarios of increasing sea surface temperature and decreasing salinity of the Baltic Sea from a global climate model were combined with two alternative fishing scenarios, and their direct and ecosystem-mediated effects (i.e., through predation by cod and competition with sprat) on the herring population were evaluated for the period 2010-2050. Gradual increase in temperature has a positive impact on the long-term productivity of the herring stock, but it has the potential to enhance the recovery of the herring stock only in combination with sustainable fisheries management (i.e., Fmsy). Conversely, projections of herring spawning stock biomass (SSB) were generally low under elevated fishing mortality levels (Fhigh), comparable with those experienced by the stock during the 1990s. Under the combined effects of long-term warming and high fishing mortality uncertainty in herring SSB projections was higher and increasing for the duration of the forecasts, suggesting a synergistic effect of fishery exploitation and climate forcing on fish populations dynamics. Our study shows that simulations of long-term fish dynamics can be an informative tool to derive expectations of the potential long-term impact of alternative future scenarios of exploitation and climate change

Bartolino, V.; Margonski, P.

2014-01-01

42

Resident fish stock status above Chief Joseph and Grand Coulee dams : 2000 annual report; ANNUAL  

International Nuclear Information System (INIS)

The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known as the Joint Stock Assessment Project (JSAP) is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (blocked area). The three-phase approach of this project will enhance the fisheries resources of the blocked area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information housed in a central location will allow managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP (NWPPC program measure 10.8B.26) is designed and guided jointly by fisheries managers in the blocked area and the Columbia Basin blocked area management plan (1998). The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of blocked area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the blocked area, identifying data gaps t the blocked area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. The use of common collection and analytical tools is essential to the process of streamlining joint management decisions. In 1999 and 2000 the project began to address some of the identified data gaps, throughout the blocked area, with a variety of newly developed sampling projects, as well as, continuing with ongoing data collection of established projects

43

Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2000 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known as the Joint Stock Assessment Project (JSAP) is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (blocked area). The three-phase approach of this project will enhance the fisheries resources of the blocked area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information housed in a central location will allow managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP (NWPPC program measure 10.8B.26) is designed and guided jointly by fisheries managers in the blocked area and the Columbia Basin blocked area management plan (1998). The initial year of the project (1997) identified the need for a central data storage and analysis facility, coordination with the StreamNet project, compilation of blocked area fisheries information, and a report on the ecological condition of the Spokane River System. These needs were addressed in 1998 by acquiring a central location with a data storage and analysis system, coordinating a pilot project with StreamNet, compiling fisheries distribution data throughout the blocked area, identifying data gaps based on compiled information, and researching the ecological condition of the Spokane River. In order to ensure that any additional information collected throughout the life of this project will be easily stored and manipulated by the central storage facility, it was necessary to develop standardized methodologies between the JSAP fisheries managers. The use of common collection and analytical tools is essential to the process of streamlining joint management decisions. In 1999 and 2000 the project began to address some of the identified data gaps, throughout the blocked area, with a variety of newly developed sampling projects, as well as, continuing with ongoing data collection of established projects.

Crossley, Brian (Spokane Tribe of Indians, Department of Natural Resources, Wellpinit, WA); Lockwood, Jr., Neil W. (Kalispel Tribe of Indians, Usk, WA); McLellan, Jason G. (Washington Department of Fish and Wildlife, Spokane, WA)

2001-01-01

44

CORMORANT (Phalacrocorax carbo sinensis AND DAMAGES ON FISH STOCK CAUSED BY CORMORANT HYPER POPULATION  

Directory of Open Access Journals (Sweden)

Full Text Available The results of recent foreign and domestic investigations on the damages found on the fish stock of cyprinid ponds and rivers caused by hyper population of cormorants are presented. Cormorant has been for almost 30 years a protected bird species in Europe. As a species which was imported to Europe, they have no any natural enemies in European area to keep bioecological balance, thus their protection resulted in increasing their populations by 25 times from 1970. Therefore, it is questionable how opportune it is to protect the bird imported in Europe from China in the 17th century by the Dutch to catch fish in England and France while the damages it caused on the fish stock of the northern Europe were known already at the beginning of the 19th century, as reported by B r e hm (1892.

Krešimir Pažur

2002-12-01

45

Duck Valley Reservoirs Fish Stocking and Operation and Maintenance, 2006-2007 Annual Progress Report.  

Energy Technology Data Exchange (ETDEWEB)

The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance (DV Fisheries) project is an ongoing resident fish program that serves to partially mitigate the loss of anadromous fish that resulted from downstream construction of the hydropower system. The project's goals are to enhance subsistence fishing and educational opportunities for Tribal members of the Shoshone-Paiute Tribes and provide resident fishing opportunities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View, Lake Billy Shaw, and Sheep Creek Reservoirs, the program is also designed to maintain healthy aquatic conditions for fish growth and survival, to provide superior facilities with wilderness qualities to attract non-Tribal angler use, and to offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period are divided into operations and maintenance plus monitoring and evaluation. Operation and maintenance of the three reservoirs include fences, roads, dams and all reservoir structures, feeder canals, water troughs and stock ponds, educational signs, vehicles and equipment, and outhouses. Monitoring and evaluation activities included creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, control of encroaching exotic vegetation, and community outreach and education. The three reservoirs are monitored in terms of water quality and fishery success. Sheep Creek Reservoir was very unproductive this year as a fishery. Fish morphometric and water quality data indicate that the turbidity is severely impacting trout survival. Lake Billy Shaw was very productive as a fishery and received good ratings from anglers. Mountain View was also productive and anglers reported a high number of quality sized fish. Water quality (specifically dissolved oxygen and temperature) is the main limiting factor in our fisheries.

Sellman, Jake; Dykstra, Tim [Shoshone-Paiute Tribes

2009-05-11

46

The use of coded wire tags to estimate cormorant predation on fish stocks in an estuary  

DEFF Research Database (Denmark)

One of the main obstacles to resolving the conflict between an increasing population of cormorants, Phalacrocorax carbo sinensis, and the fishing industry is the lack of documentation of the effect of the birds’ predation on fish stocks. Tagging and releasing fish with coded wire tags followed by intensive cormorant pellet sampling may be a viable method to measure the impact of cormorants on fish populations. To test this new method, we studied cormorant predation in a shallow estuary, where nearly 100 000 fish were tagged and more than 10 000 cormorant pellets were collected over a 3-year study period. A total of 112 tags were recovered from the collected pellets. Analyses of tag recovery data indicated considerable cormorant predation on tagged flounder, eel and salmon smolts, but the method did not deliver high-quality documentation, mainly because of limitations in pellet sampling. We conclude with recommendations to enhance the value of this method.

Jepsen, Niels; Klenke, Reinhard

2010-01-01

47

Evolutionary regime shifts in age and size at maturation of exploited fish stocks.  

Science.gov (United States)

Worldwide declines of fish stocks raise concerns about deleterious consequences of harvesting for stock abundances and individual life histories, and call for appropriate recovery strategies. Fishes in exploited stocks mature earlier at either larger or smaller sizes due to both genetic and plastic responses. The latter occur commonly when reduced competition for food leads to faster growth. Using a size-structured consumer-resource model, which accounts for both genetic and plastic responses, we show that fisheries-induced evolutionary changes in individual life history and stock properties can easily become irreversible. As a result of annual spawning, early maturation at small sizes and late maturation at large sizes can become alternative, evolutionarily and ecologically stable states under otherwise identical environmental conditions. Exploitation of late-maturing populations can then induce an evolutionary regime shift to smaller maturation sizes associated with stepwise, 1-year decreases in age at first reproduction. Complete and early fishing moratoria slowly reverse this process, but belated or partial closure of fisheries may accelerate or even instigate further evolution to smaller sizes at maturation. We suggest that stepwise decreases in maturation age can be used as early warnings of upcoming evolutionary changes, and should inspire timely restrictions of fisheries. PMID:16822746

de Roos, André M; Boukal, David S; Persson, Lennart

2006-08-01

48

State of marine fish stock in the Caspian Sea (from results of the research in 2011  

Directory of Open Access Journals (Sweden)

Full Text Available The paper analyzes the state of the main commercially valuable marine fish stock in the Caspian Sea. It was established that the present-day kilka fishery harvested the minimal amount of anchovy and big-eyed kilka. Their abundance has decreased drastically, natural spawning has declined, commercial stock becomes depleted rapidly. Annually common kilka reproduction remains at an average long-term level. The stock of marine shad is quite stable with the most abundant Dolginka shad. Population replenishment depends on the abundance of food organisms and water temperature in the northern part of the Caspian Sea. The silverside is taken as a by-catch when common kilka are harvested. Its stock is stable. It is recommended that the species harvest should be increased. Only one mullet species (golden gray mullet may be seen in catch. Its stock is quite stable while commercial catches depend on fishery management. Marine fish resources (except for anchovy and big-eyed kilka make it possible to increase their commercial exploitation.

Khodorevskaya Raisa Pavlovna

2013-04-01

49

Water Quality, Stocking Density and Parasites of Freshwater Fish in Four Selected Areas of Bangladesh  

Directory of Open Access Journals (Sweden)

Full Text Available Stocking density, water quality (depth, temperature, dissolved oxygen, pH, total ammonia, hardness as CaCO3 and total alkalinity and parasites of fishes were investigated in four selected areas (Bogra, Chandpur, Jessore and Mymensingh for a period of three years. Stocking density varied from 15.74x103 to 34.38x103 ha-1. Water quality parameters (except ammonia varied significantly from one area to another. Among the parasites, the prevalence of Trichodinids was dominant followed by Monogenians, Chilodonella spp. and Myxosporidian. Correlation on physico-chemical parameters and incidence of parasites were studied.

A.N.H. Banu

2004-01-01

50

Risk assessment in airlines stocks market  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we compared the results between stock portfolios of North American and European airlines. The model accesses the market risk using Value-at-Risk approach in both portfolios over one month period. The analysis was performed through the use of GARCH-EVT methods and Student’s-t Copula with a Monte Carlo Simulation. The assets in the financial market usually present heavy tails in their probability distributions, so, a process capable to deal with this issue is crucial to measure ...

Renato Cesar Sato

2013-01-01

51

Admixture analysis and stocking impact assessment in brown trout ( Salmo trutta ), estimated with incomplete baseline data  

DEFF Research Database (Denmark)

Studies of genetic interactions between wild and domesticated fish are often hampered by unavailability of samples from wild populations prior to population admixture. We assessed the utility of a new Bayesian method, which can estimate individual admixture coefficients even with data missing from the populations contributing to admixture. We applied the method to analyse the genetic contribution of domesticated brown trout (Salmo trutta) in samples of anadromous trout from two stocked populations with no genetic data available before stocking. Further, we estimated population level admixture proportions by the mean of individual admixture coefficients. This method proved more informative than a multidimensional scaling analysis of individual-based genetic distances and assignment tests. The results showed almost complete absence of stocked, domesticated trout in samples of trout from the rivers. Consequently, stocking had little effect on improving fisheries. In one population, the genetic contribution by domesticated trout was small, whereas in the other population, some genetic impact was suggested. Admixture in this sample of anadromous trout despite absence of stocked domesticated trout could be because of introgression by domesticated trout adopting a resident life history.

Hansen, Michael MØller; Eg Nielsen, Einar

2001-01-01

52

Brown trout ( Salmo trutta ) stocking impact assessment using microsatellite DNA markers  

DEFF Research Database (Denmark)

The genetic integrity of many salmonid fish populations is threatened by stocking of domesticated conspecifics. The purpose of this study was to assess the utility of microsatellite DNA markers for detecting loss of genetic diversity in hatchery strains, for estimating their genetic relationships, and for monitoring the genetic impact of stocking activity on wild populations of salmonid fishes. Brown trout from ten hatchery strains, one supportive breeding "strain," and five wild populations were screened for variation at eight loci. In most hatchery strains, genetic variation was comparable to that of wild populations, but three strains showed loss of allelic variation. In six of the hatchery strains, significant differentiation was observed between age classes. Genetic differentiation among all populations was moderate (F-ST = 0.065, p(ST) = 0.076), and only a minor part of genetic diversity was distributed between the wild and hatchery populations. We assessed whether wild populations were introgressed by stocked hatchery trout by performing assignment tests to determine population of origin and estimating maximum potential introgression rates. The results suggested that genetic introgression by hatchery trout had occurred for only two of the five populations potentially influenced by stocking. In one of these two rivers, microsatellite data obtained from a limited number of old scale samples indicated that individuals from the original population were genetically divergent from these of the present population, suggesting that extinction of the original population had taken place. The study demonstrates that microsatellite analysis provides a useful tool for distinguishing heavily introgressed populations from those unaffected by stocking. The information can be used to assist in (1) prioritizing populations for conservation and (2) the choice of wild populations to be used as sources for the reintroduction of salmonids in areas where local, indigenous gene pools have been extirpated.

Hansen, Michael MØller; Eg Nielsen, Einar

2001-01-01

53

An Individual-based Probabilistic Model for Fish Stock Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available We define an individual-based probabilistic model of a sole (Solea solea behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA, a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made available for its adaptation to other species.

Federico Buti

2010-08-01

54

An Individual-based Probabilistic Model for Fish Stock Simulation  

CERN Document Server

We define an individual-based probabilistic model of a sole (Solea solea) behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA), a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made avai...

Buti, Federico; Merelli, Emanuela; Paschini, Elio; Penna, Pierluigi; Tesei, Luca; 10.4204/EPTCS.33.3

2010-01-01

55

Does the optimal size of a fish stock increase with environmental uncertainties?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze the effect of environmental uncertainties on optimal fishery management in a bio-economic fishery model. Unlike most of the literature on resource economics, but in line with ecological models, we allow the different biological processes of survival and recruitment to be affected differently by environmental uncertainties. We show that the overall effect of uncertainty on the optimal size of a fish stock is ambiguous, depending on the prudence of the value function. For the case of...

Kapaun, Ute; Quaas, Martin F.

2012-01-01

56

Duck Valley Reservoirs Fish Stocking and O&M, Annual Progress Report 2007-2008.  

Energy Technology Data Exchange (ETDEWEB)

The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance Project (DV Fisheries) is an ongoing resident fish program that serves to partially mitigate the loss of anadromous fish that resulted from downstream construction of the federal hydropower system. The project's goals are to enhance subsistence fishing and educational opportunities for Tribal members of the Shoshone-Paiute Tribes and provide fishing opportunities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View (MVR), Lake Billy Shaw (LBS), and Sheep Creek Reservoirs (SCR), the program is also designed to: maintain healthy aquatic conditions for fish growth and survival, provide superior facilities with wilderness qualities to attract non-Tribal angler use, and offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period fall into three categories: operations and maintenance, monitoring and evaluation, and public outreach. Operation and maintenance of the three reservoirs include maintaining fences, roads, dams and all reservoir structures, feeder canals, water troughs, stock ponds, educational signs, vehicles, equipment, and restroom facilities. Monitoring and evaluation activities include creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, and control of encroaching exotic vegetation. Public outreach activities include providing environmental education to school children, providing fishing reports to local newspapers and vendors, updating the website, hosting community environmental events, and fielding numerous phone calls from anglers. The reservoir monitoring program focuses on water quality and fishery success. Sheep Creek Reservoir and Lake Billy Shaw had less than productive trout growth due to water quality issues including dissolved oxygen and/or turbidity. Regardless, angler fishing experience was the highest at Lake Billy Shaw. Trout in Mountain View Reservoir were in the best condition of the three reservoirs and anglers reported very good fishing there. Water quality (specifically dissolved oxygen and temperature) remain the main limiting factors in the fisheries, particularly in late August to early September.

Sellman, Jake; Perugini, Carol [Department of Fish, Wildlife, and Parks, Shoshone-Paiute Tribes

2009-02-20

57

Duck Valley Reservoirs Fish Stocking and Operation and Maintenance, 2005-2006 Annual Progress Report.  

Energy Technology Data Exchange (ETDEWEB)

The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance (DV Fisheries) project is an ongoing resident fish program designed to enhance both subsistence fishing, educational opportunities for Tribal members of the Shoshone-Paiute Tribes, and recreational fishing facilities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View, Lake Billy Shaw, and Sheep Creek Reservoirs, the program also intends to afford and maintain healthy aquatic conditions for fish growth and survival, to provide superior facilities with wilderness qualities to attract non-Tribal angler use, and to offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period are divided into operations and maintenance plus monitoring and evaluation. Operation and maintenance of the three reservoirs include fences, roads, dams and all reservoir structures, feeder canals, water troughs and stock ponds, educational signs, vehicles and equipment, and outhouses. Monitoring and evaluation activities included creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, control of encroaching exotic vegetation, and community outreach and education. The three reservoirs are monitored in terms of water quality and fishery success. Sheep Creek Reservoir was the least productive as a result of high turbidity levels and constraining water quality parameters. Lake Billy Shaw trout were in poorer condition than in previous years potentially as a result of water quality or other factors. Mountain View Reservoir trout exhibit the best health of the three reservoirs and was the only reservoir to receive constant flows of water.

Sellman, Jake; Dykstra, Tim [Shoshone-Paiute Tribes

2009-05-11

58

Risk assessment in airlines stocks market  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we compared the results between stock portfolios of North American and European airlines. The model accesses the market risk using Value-at-Risk approach in both portfolios over one month period. The analysis was performed through the use of GARCH-EVT methods and Student’s-t Copula with a Monte Carlo Simulation. The assets in the financial market usually present heavy tails in their probability distributions, so, a process capable to deal with this issue is crucial to measure the risk of loss. We analyzed the period from mid-2007 to mid-2012 to compose comparison between these two portfolios. The financial crisis of 2008 had a great impact in the North America market in relative to the European market. The central role of transport in the economy makes studies dealing with investment risk measure in this sector crucial for the industrial development. The volatility of risk in the airline market happens by internal and external motives and the methodological development of financial tools can offer an important contribution due the investment flux dependency.

Renato Cesar Sato

2013-04-01

59

ss3sim: an R package for fisheries Stock Assessment simulation with stock synthesis.  

Science.gov (United States)

Simulation testing is an important approach to evaluating fishery stock assessment methods. In the last decade, the fisheries stock assessment modeling framework Stock Synthesis (SS3) has become widely used around the world. However, there lacks a generalized and scriptable framework for SS3 simulation testing. Here, we introduce ss3sim, an R package that facilitates reproducible, flexible, and rapid end-to-end simulation testing with SS3. ss3sim requires an existing SS3 model configuration along with plain-text control files describing alternative population dynamics, fishery properties, sampling scenarios, and assessment approaches. ss3sim then generates an underlying 'truth' from a specified operating model, samples from that truth, modifies and runs an estimation model, and synthesizes the results. The simulations can be run in parallel, reducing runtime, and the source code is free to be modified under an open-source MIT license. ss3sim is designed to explore structural differences between the underlying truth and assumptions of an estimation model, or between multiple estimation model configurations. For example, ss3sim can be used to answer questions about model misspecification, retrospective patterns, and the relative importance of different types of fisheries data. We demonstrate the software with an example, discuss how ss3sim complements other simulation software, and outline specific research questions that ss3sim could address. PMID:24699270

Anderson, Sean C; Monnahan, Cole C; Johnson, Kelli F; Ono, Kotaro; Valero, Juan L

2014-01-01

60

75 FR 6058 - Federal Sport Fish Restoration; California Department of Fish and Game Fish Hatchery and Stocking...  

Science.gov (United States)

...FWS-R8-MB-2009-N286; 80213-9410-0000-7B] Federal Sport Fish Restoration; California Department...jointly prepared with CDFG. Under the Sport Fish Restoration Act (SFRA), FWS proposes...authority to grant Federal funds from the Sport Fish Restoration and Boating Trust...

2010-02-05

 
 
 
 
61

Assessing the suitability of a partial water reuse system for rearing juvenile Chinook salmon for stocking in Washington State.  

Science.gov (United States)

To assess the suitability of water reuse technology for raising Pacific salmon Oncorhynchus spp. for stocking purposes, fish health and welfare were compared between two groups of juvenile Chinook salmon O. tshawytscha from the same spawn: one group was reared in a pilot partial water reuse system (circular tanks), and the other group was reared in a flow-through raceway. This observational study was carried out over a 21-week period in Washington State. Reuse and raceway fish were sampled repeatedly for pathogen screening and histopathology; fin erosion and whole-blood characteristics were also evaluated. By the study's end, no listed pathogens were isolated from either cohort, and survival was 99.3% and 99.0% in the reuse and raceway groups, respectively. Condition factor was 1.28 in raceway fish and 1.14 in reuse fish; this difference may have been attributable to occasional differences in feeding rates between the cohorts. Fin indices (i.e., length of the longest dorsal or caudal fin ray, standardized by fork length) were lower in reuse fish than in raceway fish, but fin erosion was not grossly apparent in either cohort. The most consistent histological lesion was gill epithelial hypertrophy in reuse fish; however, blood analyses did not suggest any corresponding physiological imbalances. Overall, results suggest that water reuse technology can be employed in rearing juvenile anadromous salmonids for stocking purposes. PMID:21834328

Good, Christopher; Vinci, Brian; Summerfelt, Steven; Snekvik, Kevin; Adams, Ian; Dilly, Samuel

2011-06-01

62

Annual Coded Wire Tag Program; Oregon Stock Assessment, 2001 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

This annual report is in fulfillment of contract obligations with Bonneville Power Administration which is the funding source for the Oregon Department of Fish and Wildlife project 'Annual Stock Assessment - Coded Wire Tag Program (ODFW)'. Results for the 2001 contract period: Objective 1--Over 1 million juvenile salmon were coded-wire by this program (Table 1); Objective 2--ODFW recovered and processed over 40,000 snout collected from coded-wire tagged fish (Table 2); Objective 3--Survival data is summarized below; Objective 4--The last group of VIE tagged coho was released in 2001 and returning coho were samples at Sandy Hatchery. This sampling showed only 1 of 1,160 returning coho VIE marked as juveniles retained the VIE mark as adults.

Lewis, Mark; Mallette, Christine; Murray, William

2002-03-01

63

Spawning frequency of brood dams and sires in a marine fish stock-enhancement hatchery.  

Science.gov (United States)

Parentage analysis, employing five hypervariable microsatellite markers, was used to follow spawning patterns of red drum Sciaenops ocellatus broodfish in two spawning tanks through most of a calendar year in a marine fish hatchery dedicated to stock enhancement. Five of six dams and all four sires spawned at least once during the year. Variation in dam and sire spawning incidence and in number of progeny produced per dam and per sire translated into reduced genetic effective size (N e) per spawn by 40·6% in one tank and 50·8% in the other. PMID:20840629

Gold, J R; Renshaw, M A; Saillant, E; Vega, R R

2010-09-01

64

76 FR 61092 - Stock Assessment Reports for Dusky, Sandbar, and Blacknose Sharks in the U.S. Atlantic and Gulf...  

Science.gov (United States)

...Atmospheric Administration RIN 0648-XA662 Stock Assessment Reports for Dusky, Sandbar...NMFS announces the availability of final stock assessment reports for dusky, sandbar...describe methodologies used to determine stock statuses, and detail relevant...

2011-10-03

65

Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines in Alberta, Canada  

Science.gov (United States)

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se 15 ?g/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational "put and take" fisheries.

Miller, L. L.; Rasmussen, J. B.; Palace, V. P.; Sterling, G.; Hontela, A.

2013-07-01

66

Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management  

DEFF Research Database (Denmark)

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries?induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life?history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.

Laugen, Ane T; Engelhard, Georg H

2014-01-01

67

Summary & Analysis of the Resumed Review Conference of the UN Fish Stocks Agreement, 24-28 May 2010, New York, United States of America  

...management of fish stocks, including outcomes on sharks, the ecosystem approach, excess fishing capacity and developing statesrsquo; abilities to develop their fisheries. ...alia: integrate ecosystem considerations in fisheries management; reduce urgently the worldrsquo;s fishing capacity to levels commensurate with the sustainability of fish stocks; ...minimum standards for port state measures and a comprehensive global register of fishing vessels; expand assistance to developing countries; and establish a ...and the control, monitoring and surveillance of illegal, unreported and unregulated (IUU) fishing (ICSP 6); non-parties and a follow up to ...

68

Fish stock assessment of piraputanga Brycon microlepis in the Cuiabá River basin, Pantanal of Mato Grosso, Brazil Avaliação do estoque pesqueiro da piraputanga Brycon microlepis na bacia do rio Cuiabá, Pantanal Mato-grossense  

Directory of Open Access Journals (Sweden)

Full Text Available Fork length measurements of individuals of Brycon microlepis landed and commercialized at the Porto Market in Cuiabá, MT, from May-October 1996 to May-October 1997 were used to estimate growth and mortality parameters for this species. The average estimated populational parameters were: L¥ = 705 mm, k = 0.275 year--1, C = 0.775, WP = 0.465, Lc = 164 mm, M = 0.585 year--1, Z = 0.822 year--1, with F = 0.237 year--1. Yield per recruit analysis suggests that the stock is not yet overexploited.Medidas de comprimento furcal obtidas de exemplares de Brycon microlepis desembarcados e comercializados no Mercado do Porto em Cuiabá, MT, no período de maio a outubro de 1996 e de maio a outubro de 1997, foram utilizadas para a obtenção de estimativas dos parâmetros de crescimento e mortalidade da espécie. Os parâmetros populacionais médios estimados foram: L¥ = 705 mm; k = 0,275 ano--1; C = 0,775; WP = 0,465; Lc = 164 mm; M = 0,585 ano--1; Z = 0,822 ano--1, sendo F = 0,237 ano--1. A análise do rendimento por recruta e a taxa de explotação indicam que o rendimento máximo sustentável não foi alcançado. Portanto, o estoque ainda não está sobreexplotado.

L. A. de F. MATEUS

2002-02-01

69

Poor-data and data-poor species stock assessment using a Bayesian hierarchical approach.  

Science.gov (United States)

Appropriate inference for stocks or species with low-quality data (poor data) or limited data (data poor) is extremely important. Hierarchical Bayesian methods are especially applicable to small-area, small-sample-size estimation problems because they allow poor-data species to borrow strength from species with good-quality data. We used a hammerhead shark complex as an example to investigate the advantages of using hierarchical Bayesian models in assessing the status of poor-data and data-poor exploited species. The hammerhead shark complex (Sphyrna spp.) along the Atlantic and Gulf of Mexico coasts of the United States is composed of three species: the scalloped hammerhead (S. lewini), the great hammerhead (S. mokarran), and the smooth hammerhead (S. zygaena) sharks. The scalloped hammerhead comprises 70-80% of the catch and has catch and relative abundance data of good quality, whereas great and smooth hammerheads have relative abundance indices that are both limited and of low quality presumably because of low stock density and limited sampling. Four hierarchical Bayesian state-space surplus production models were developed to simulate variability in population growth rates, carrying capacity, and catchability of the species. The results from the hierarchical Bayesian models were considerably more robust than those of the nonhierarchical models. The hierarchical Bayesian approach represents an intermediate strategy between traditional models that assume different population parameters for each species and those that assume all species share identical parameters. Use of the hierarchical Bayesian approach is suggested for future hammerhead shark stock assessments and for modeling fish complexes with species-specific data, because the poor-data species can borrow strength from the species with good data, making the estimation more stable and robust. PMID:22073653

Jiao, Yan; Cortés, Enric; Andrews, Kate; Guo, Feng

2011-10-01

70

A reliable method for ageing of whiting (Merlangius merlangus) for use in stock assessment and management  

DEFF Research Database (Denmark)

Accurate age estimation is important for stock assessment and management. The importance of reliable ageing is emphasized by the impending analytical assessment of whiting (Merlangius merlangus) in the Baltic Sea. Whiting is a top predator in the western Baltic Sea, where it is fished commercially although less extensively compared to the North Sea. Although the species is considered one of the most difficult gadoids to age, few efforts have been made to shed light on the ageing problems. The aim of the present study was to identify and validate the 1st winter ring and to examine the visibility of the subsequent winter rings. Microstructure analysis was used to confirm the 1st winter ring. Additionally, otolith growth trajectories were obtained, confirming the allometric growth as seen in many fish species. The method for ageing of whole otoliths presented in this study can be directly implemented in future ageing of whiting otoliths from the Baltic Sea – and potentially also adjacent areas where the conspecifics have similar growth rates

Ross, Stine Dalmann; Hüssy, Karin

2013-01-01

71

Biochemical Assessment of Selected Fresh Fish  

Directory of Open Access Journals (Sweden)

Full Text Available Ten fresh fish samples of different species (Mugil cephalus, Setipinna phasa, Coilia dussumieri, Scatophagus argus, Sillanopsis panijus, Arius caelatus, Hilsa ilisha, Polynemus paradiseus, Platicephalus indicus and Pelamys chiliensis collected from Kuakata, Bangladesh were assessed biochemically (proximate composition, total volatile basic nitrogen, tri-methyl amine and pH. Moisture content of fresh fish varied over a range from 65.33 to 78.92%. Likewise, protein (8.58 to 19.06%, fat (6.12 to 12.99% and ash (1.07 to 8.41% content indicated wide variation in the ten fresh fish analysed. TVB-N and TMA-N values of fresh fish were found ranging between 10.92 ± 0.23 to 25.75 ± 0.80 mg N 100 g-1 and 7.70 ± 0.67 to 18.50 ± 0.77, respectively. The values of pH of the samples ranged from 7.03 ± 0.05 to 6.7 ± 0.07.

K. Azam

2004-01-01

72

Caracterización genética de lotes de peces usados en programas de repoblamiento y su importancia en la conservación genética en la piscicultura / Genetic characterization of fish stocks used in stocking programas and their importance in the fish farm genetic conservation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish En las últimas décadas se ha verificado la desaparición de varias especies de peces debido principalmente a impactos generados por acciones humanas. Programas de repoblamiento vienen siendo cada vez más usados como métodos de conservación de la ictiofauna. Sin embargo, sin una correcta orientación g [...] enética y reproductiva de los lotes utilizados en estos programas, poblaciones naturales de peces y el ecosistema pueden ser afectados. El objetivo del siguiente estudio fue determinar la variabilidad genética de seis lotes de peces usados en programas de repoblamiento, mediante el marcador molecular RAPD. Se analizaron 180 alevines de tres especies de peces (Leporinus elongatus, Piaractus mesopotamicus y Prochilodus lineatus) en tres estaciones piscícolas, ubicadas en las ciudades de Rolândia, Andirá y Palotina en el estado de Paraná, Brasil. Los valores de variabilidad genética estimados por el porcentaje de fragmentos polimórficos y por el índice de diversidad de Shannon mostraron una alta variabilidad genética entre los lotes de L. elongatus y P. lineatus, debido posiblemente al efecto fundador y al manejo reproductivo adoptado en cada piscícola. Se determinó que existió baja diferenciación genética entre los lotes de P. mesopotamicus. Los resultados de este estudio posibilitaran el correcto manejo reproductivo y genético de los lotes de cada piscícola y la orientación objetiva de programas de repoblamiento, permitiendo la conservación de la variabilidad genética, factor de gran importancia en ambientes en cautiverio. Abstract in english In the last decades it has been verified the decrease and extinction of fish several species mainly to impacts generated by human actions. Stocking programs are being used as conservation methods of the ichthyofauna. However, without a correct genetic and reproductive orientation of the stocks used [...] in these programs, natural fish populations and the ecosystem can be affected. The objective of the following study was to determine the genetic variability of six fish stocks used in stocking programs, by means of the RAPD molecular marker. There were analyzed 180 juveniles of three fish species (Prochilodus lineatus, Piaractus mesopotamicus, and Leporinus elongatus) from three fish farms, located in the Rolândia, Andirá, and Palotina cities in Paraná state, Brazil. The genetic variability values estimated by the percentage of polymorphic fragments and by the Shannon diversity index showed a high genetic variability between the P. lineatus and L. elongatus stocks, due possibly to the founder effect and the reproductive management adopted in each fish farm. It was determined that low genetic differentiation existed among the P. mesopotamicus stocks. The results of this study facilitated the correct reproductive and genetic management of the stocks of each fish farm and the objective orientation of stocking programs, allowing the conservation of the genetic variability, factor of great importance in captivity environments.

Nelson M, Lopera Barrero; Ricardo, Pereira Ribeiro; Jayme A, Povh; Patrícia C, Gomes; Lauro, Vargas; Sheila, Nogueira de Oliveira.

2008-12-01

73

Caracterización genética de lotes de peces usados en programas de repoblamiento y su importancia en la conservación genética en la piscicultura / Genetic characterization of fish stocks used in stocking programas and their importance in the fish farm genetic conservation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish En las últimas décadas se ha verificado la desaparición de varias especies de peces debido principalmente a impactos generados por acciones humanas. Programas de repoblamiento vienen siendo cada vez más usados como métodos de conservación de la ictiofauna. Sin embargo, sin una correcta orientación g [...] enética y reproductiva de los lotes utilizados en estos programas, poblaciones naturales de peces y el ecosistema pueden ser afectados. El objetivo del siguiente estudio fue determinar la variabilidad genética de seis lotes de peces usados en programas de repoblamiento, mediante el marcador molecular RAPD. Se analizaron 180 alevines de tres especies de peces (Leporinus elongatus, Piaractus mesopotamicus y Prochilodus lineatus) en tres estaciones piscícolas, ubicadas en las ciudades de Rolândia, Andirá y Palotina en el estado de Paraná, Brasil. Los valores de variabilidad genética estimados por el porcentaje de fragmentos polimórficos y por el índice de diversidad de Shannon mostraron una alta variabilidad genética entre los lotes de L. elongatus y P. lineatus, debido posiblemente al efecto fundador y al manejo reproductivo adoptado en cada piscícola. Se determinó que existió baja diferenciación genética entre los lotes de P. mesopotamicus. Los resultados de este estudio posibilitaran el correcto manejo reproductivo y genético de los lotes de cada piscícola y la orientación objetiva de programas de repoblamiento, permitiendo la conservación de la variabilidad genética, factor de gran importancia en ambientes en cautiverio. Abstract in english In the last decades it has been verified the decrease and extinction of fish several species mainly to impacts generated by human actions. Stocking programs are being used as conservation methods of the ichthyofauna. However, without a correct genetic and reproductive orientation of the stocks used [...] in these programs, natural fish populations and the ecosystem can be affected. The objective of the following study was to determine the genetic variability of six fish stocks used in stocking programs, by means of the RAPD molecular marker. There were analyzed 180 juveniles of three fish species (Prochilodus lineatus, Piaractus mesopotamicus, and Leporinus elongatus) from three fish farms, located in the Rolândia, Andirá, and Palotina cities in Paraná state, Brazil. The genetic variability values estimated by the percentage of polymorphic fragments and by the Shannon diversity index showed a high genetic variability between the P. lineatus and L. elongatus stocks, due possibly to the founder effect and the reproductive management adopted in each fish farm. It was determined that low genetic differentiation existed among the P. mesopotamicus stocks. The results of this study facilitated the correct reproductive and genetic management of the stocks of each fish farm and the objective orientation of stocking programs, allowing the conservation of the genetic variability, factor of great importance in captivity environments.

Nelson M, Lopera Barrero; Ricardo, Pereira Ribeiro; Jayme A, Povh; Patrícia C, Gomes; Lauro, Vargas; Sheila, Nogueira de Oliveira.

74

[Stocking with bluegill sunfish, Lepomis macrochirus, by fisheries experimental stations, fishing tackle makers, and anglers in Japan, 1960-1975].  

Science.gov (United States)

This paper discusses some facts that were pivotal in the process of the introduction of Bluegill Sunfish, Lepomis macrochirus, into various places in Japan, however have not been considered in the existing literature. This paper points out that L. macrochirus escaped, and also was stocked, to the open water in Osaka as a result of experiments by a fisheries experimental station in the 1960s and early 1970s. In Shiga Prefecture too, the fish escaped into Lake Biwa as a result of experiments by a fisheries experimental station in about 1969. Neither Osaka nor Shiga are mentioned, by previous studies based on questionnaire research, as the prefectures in which L. macrochirus inhabited in the years between 1960, when the fish was first introduced into Japan, and 1979. In addition, anglers, who considered L. macrochirus an ideal game fish, stocked ponds and lakes in some prefectures with L. macrochirus in around 1970 on purpose to multiply the species. During this process, a network among not only local governments, fisheries experimental stations, and fish farmers, but also industries targeting anglers, such as fishing tackle makers and a magazine for anglers, was being formed, which however did not get established after all. These findings will contribute to enrich the basis of today's genetic research on the distribution of L. macrochirus in Japan. PMID:25296515

Watanabe, Hiroyuki

2014-07-01

75

Development and sensitivity analysis of impact assessment equations based on stock-recruitment theory  

International Nuclear Information System (INIS)

A central and unresolved problem in assessing the impact of power plant operations on Hudson River fish populations was the prediction of long-term population changes resulting from impingement and entrainment mortality. A series of equations was developed from the Ricker and Beverton-Holt stock-recruitment models to address this issue. It was assumed that compensation occurs during a brief period early in the life cycle rather than throughout the life cycle. Equations were developed for the added power plant-induced mortality occurring before or after compensation in each model. Mortality added after compensation resulted in larger estimates of population reduction than mortality added before compensation. The simple deterministic and more complex age-structured models provided identical predictions of long-term changes in population size in most cases. Similarly, the simple models predicted population changes that were nearly identical to the average age-structured model with variable survival except when levels of variation were quite high and the population modeled was semelparous. Advantages of the equations developed herein are their simplicity, generality, and minimal data requirements. The predictions of long-term population changes resulting from impingement and entrainment mortality were not attained. The magnitude and form of the compensatory responses of Hudson River fish populations remained undetermined, so that an agreement on this critical component of prediction models could not be reached. 33 refs., 4 figs., 2 tabs

76

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción The influence of environment on stock assessment: an approach with surplus production models  

Directory of Open Access Journals (Sweden)

Full Text Available Los modelos de producción convencionales no son adecuados para ciertos stocks, porque las variaciones del esfuerzo de pesca explican sólo una parte de la variabilidad total de las capturas anuales. A menudo la variación residual es originada por fenómenos ambientales, que afectan la abundancia y/o la capturabilidad del stock de un año a otro. En consecuencia, se ha incluido en los modelos convencionales una variable ambiental para mejorar la exactitud. Esta variable aparece en las fórmulas a nivel de la abundancia, de la capturabilidad, o de ambas. Estos modelos son desarrollados a partir del modelo de producción lineal de Schaefer, del exponencial de Fox o del generalizado de Pella y Tomlinson. CLlMPROD es un sistema-experto experimental que proporciona una descripción estadística y gráfica de los datos y permite la selección del modelo correspondiente según los criterios objetivos del usuario. El software ajusta los modelos usando rutinas de regresión no-lineal, evalúa el ajuste a través de tests paramétricos y no-paramétricos, y proporciona una representación gráfica de los resultados. Se consideran las limitaciones de este tipo de modelos. No obstante, éstos pueden proporcionar una interpretación bastante acertada de la historia de la pesquería, particularmente en el caso de stocks que colapsan inesperadamente sin ningún aumento apreciable del esfuerzo de pesca. Estos modelos también pueden ser útil en el manejo eficiente de este tipo de pesquerías, cuando los fenómenos climáticos pueden ser pronosticados o cuando su influencia esté restringida a la explotación del año(s anterior. Finalmente se presenta el análisis de dos pesquerías colapsadas por una combinación de sobrepesca y cambios ambientales: la pesquería de sardina de Senegal y la de anchoveta del Pacífico surorientalConventional global production models are not suitable for certain stocks, because fishing effort variations explain only a part of the total variability of annual catches. Often the residual variability originates from the influence of environmental phenomena, which affect either the abundance or the catchability of a stock from one year to the next. Therefore, an additional environmental variable has been inserted into conventional models in order to improve their aeeuracy. This variable appear in simple formulae concerning either stock abundance, or the catchability coefficient, or both. The models were developed from Schaefer's linear production model, Fox's exponential model or Pella and Tomlinson generalised model. CLlMPROD is an experimental expert-system, using artificial intelligence, which provides a statistical and graphical description of the data set and helps the user to select the model corresponding to his case according to objective eriteria. The software fits the model to the data set using a non-linear regression routine, assesses the fit with parametric and non-parametric tests, and provides a graphical representation of the results. Limitations of this kind of model are considered. The models can provide a fairly good interpretación of fishery history, particularly when a stock collapses unexpectedly without any appreciable increase in the nominal fishing effort. These models can also pro vide a useful tool efficient management of a fishery in those instances where climatic phenomena can be forecast, or when their influence is restricted to the year(s preceding exploitation. Finally, the analysis of two fisheries collapsed by a combination of overfishing and environmental changes is presented: the Senegalese sardine fishery and the south-east Pacific anchovy fishery

Pierre Fréon

1995-01-01

77

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción / The influence of environment on stock assessment: an approach with surplus production models  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Los modelos de producción convencionales no son adecuados para ciertos stocks, porque las variaciones del esfuerzo de pesca explican sólo una parte de la variabilidad total de las capturas anuales. A menudo la variación residual es originada por fenómenos ambientales, que afectan la abundancia y/o l [...] a capturabilidad del stock de un año a otro. En consecuencia, se ha incluido en los modelos convencionales una variable ambiental para mejorar la exactitud. Esta variable aparece en las fórmulas a nivel de la abundancia, de la capturabilidad, o de ambas. Estos modelos son desarrollados a partir del modelo de producción lineal de Schaefer, del exponencial de Fox o del generalizado de Pella y Tomlinson. CLlMPROD es un sistema-experto experimental que proporciona una descripción estadística y gráfica de los datos y permite la selección del modelo correspondiente según los criterios objetivos del usuario. El software ajusta los modelos usando rutinas de regresión no-lineal, evalúa el ajuste a través de tests paramétricos y no-paramétricos, y proporciona una representación gráfica de los resultados. Se consideran las limitaciones de este tipo de modelos. No obstante, éstos pueden proporcionar una interpretación bastante acertada de la historia de la pesquería, particularmente en el caso de stocks que colapsan inesperadamente sin ningún aumento apreciable del esfuerzo de pesca. Estos modelos también pueden ser útil en el manejo eficiente de este tipo de pesquerías, cuando los fenómenos climáticos pueden ser pronosticados o cuando su influencia esté restringida a la explotación del año(s) anterior. Finalmente se presenta el análisis de dos pesquerías colapsadas por una combinación de sobrepesca y cambios ambientales: la pesquería de sardina de Senegal y la de anchoveta del Pacífico suroriental Abstract in english Conventional global production models are not suitable for certain stocks, because fishing effort variations explain only a part of the total variability of annual catches. Often the residual variability originates from the influence of environmental phenomena, which affect either the abundance or t [...] he catchability of a stock from one year to the next. Therefore, an additional environmental variable has been inserted into conventional models in order to improve their aeeuracy. This variable appear in simple formulae concerning either stock abundance, or the catchability coefficient, or both. The models were developed from Schaefer's linear production model, Fox's exponential model or Pella and Tomlinson generalised model. CLlMPROD is an experimental expert-system, using artificial intelligence, which provides a statistical and graphical description of the data set and helps the user to select the model corresponding to his case according to objective eriteria. The software fits the model to the data set using a non-linear regression routine, assesses the fit with parametric and non-parametric tests, and provides a graphical representation of the results. Limitations of this kind of model are considered. The models can provide a fairly good interpretación of fishery history, particularly when a stock collapses unexpectedly without any appreciable increase in the nominal fishing effort. These models can also pro vide a useful tool efficient management of a fishery in those instances where climatic phenomena can be forecast, or when their influence is restricted to the year(s) preceding exploitation. Finally, the analysis of two fisheries collapsed by a combination of overfishing and environmental changes is presented: the Senegalese sardine fishery and the south-east Pacific anchovy fishery

Pierre, Fréon; Eleuterio, Yáñez R.

78

Otter ( Lutra lutra ) predation on stocked brown trout ( Salmo trutta ) in two Danish lowland rivers  

DEFF Research Database (Denmark)

This study aimed to evaluate otter predation on stocked trout. Large hatchery-reared trout (16-30 cm) were stocked into two Danish rivers with different fish populations. Otter diet before and after trout stocking was determined by analysing 685 spraints, collected regularly during the 35-day study period. Fish composition in the rivers before stocking was assessed by electrofishing. In River Trend, a typical trout river, the proportion of trout in the otter diet increased from 8% before stocking to 33% a few days after stocking. Moreover, trout lengths in the diet changed significantly towards the lengths of stocked trout, indicating that newly stocked trout were preferred to wild trout. In River Skals, dominated by cyprinids, there was no change in otter diet after stocking of hatchery trout, i.e., these were ignored by otter. Otter predation should be taken into account together with fish and bird predation, when stocking is used as a measure for conserving endangered salmonid populations.

Jacobsen, Lene

2005-01-01

79

78 FR 32377 - Draft 2012 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...abundance of the stock, population growth rates and trends, estimates of annual human-caused...mortality exceeds the potential biological removal level; (B) which, based on the best...causes of stranded marine mammals on Cape Cod and southeastern Massachusetts...

2013-05-30

80

Relationship between horizontal hydroacoustic stock estimates and gillnet catches of surface-oriented fish in shallow Lake Balaton (Hungary  

Directory of Open Access Journals (Sweden)

Full Text Available We examined whether gillnetting and hydroacoustics provide comparable relative fish density and fish size distribution estimates in the uppermost water layer of a shallow turbid lake and whether the inclusion of environmental and stock parameters could improve comparability of data between different gears. According to gillnetting, most fish shorter than 14 cm in total length were Alburnus alburnus, and most fish longer than 14 cm were Pelecus cultratus. Size distributions and median sizes obtained from gillnetting and acoustics differed. Pure acoustics-derived density estimates accounted for only <8.8% of the variation in the gillnet catch by number and no correlation was found in biomass indices. Most variances observed in the gillnet catch-per-unit-effort data were associated with water transparency, none of the other investigated variables had significant explanatory power. We conclude that the feasibility of establishing a powerful model describing the relationship between fish density estimates of gillnetting and acoustics is low in shallow and turbid habitats, and it might be successful only if the crucial sampling and environmental parameters affecting catch efficiency of gillnets and post-processing of acoustic data are considered. This study cautions again that gillnetting should be used carefully to analyse trends of fish abundance.

György Á.I.

2012-06-01

 
 
 
 
81

Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries  

Science.gov (United States)

We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

Neira, Sergio; Arancibia, Hugo

2013-10-01

82

Principles of fish welfare assessment in farm rearing conditions  

Directory of Open Access Journals (Sweden)

Full Text Available For several decades fish welfare has been subject of many researches, and the interest for this subject is connected with the fact that fish can feel pain and suffering. In addition to this stressors’ mechanisms of action and their consequences are similar in mammals and fish. Assessment of welfare for farmed fish is based on the same principles as for terrestrial farm animals. However, special methods of collecting data are needed due to morphological characteristics of fish and properties of their environment. In the world and in our country, researches of different ways of fish welfare assessment are being conducted, especially based on non-invasive techniques such as monitoring of behaviour. In this paper a review of basic principles and methods used in assessment of farmed fish welfare is given.

Reli? Renata R.

2010-01-01

83

A two-stage biomass random effects model for stock assessment without catches: What can be estimated using only biomass survey indices?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A simple two-stage biomass random effects population dynamics model is presented for carrying out fish stock assessments based on survey indices using no commercial catch information. Recruitment and biomass growth are modelled as random effects, reducing the number of model parameters while maintaining model flexibility. No assumptions regarding natural mortality rates are required. The performance of the method was evaluated using simulated data with emphasis on identifying parameter redund...

Trenkel, Verena

2008-01-01

84

Evolutionary impact assessment: Accounting for the evolutionary consequences of fishing in an ecosystem approach to fisheries management  

DEFF Research Database (Denmark)

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries-induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life-history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries

Laugen, Ane T.; Engelhard, Georg H.

2014-01-01

85

Stock Assessment of the Common Octopus (Octopus vulgaris in Monastir; the Mid-eastern Coast of Tunisia  

Directory of Open Access Journals (Sweden)

Full Text Available The common octopus, (Octopus vulgaris Cuvier, 1797 is widely distributed through the world. It represents an important resource with high economic value. It is exploited by trawl and by other gears such as trammel net, pots and it is also captured by diving. Although the multitude of assessment techniques, few fisheries cephalopods were well managed. In Tunisia, common octopus (Octopus vulgaris is captured particularly in southern coast and the Sahel defined by three regions (Mahdia, Sousse and Monastir. Our study constitutes the first assessment stock in Monastir situated in the mid of the eastern coasts of Tunisia. Using surplus production models, an under fishing state of Octopus in the East of Tunisia is shown. This study confirms also the necessity of the incorporation of environmental parameters for a better explanation of the variability of common octopus abundance and the importance of these results in the assessment and management of this species.

Widien Khoufi

2012-11-01

86

ASSESSMENT OF STOCK AND SPATIAL DISTRIBUTION OF SOLE (SOLEA SOLEA, L. IN ALBANIAN COAST USING RAPIDO TRAWL  

Directory of Open Access Journals (Sweden)

Full Text Available Common sole (Solea solea Linnaeus, 1758 is still not a specific target of fishery in Albania, but it represents an important target of the mixed-species catches of bottom trawlers and set netters operating in the coastal areas in the upper part of Albanian Adriatic Sea. Sole landings are low, amounting very few tonnes, but the demand will likely increase in the next future, because of the high quality of the fish fillet and the increase of consumers demand for wild sea fish. In order to identify the spawning areas and assess the spatial distribution and biomass of this species a rapido trawl survey was performed in year 2007. The smallest specimens were mostly concentrated in the shallowest stratum and the largest ones between 30 and 100 m depth. Solea Stock Biomass (SSB was 354 t, corresponding to 64% of the overall population recorded at sea at that time. In the context of fisheries, the Albanian fishing fleet involve a number of different fishing gears, while rapido trawl is introduced recently. The special technical and operating characteristics of rapido trawl makes it very effective in sole fishery and less harmful for the sea benthos and the species inhabiting it. This study aimed the estimation of spatial distribution of common sole and its biomass in the Albanian coast using rapido trawl gear.

Enton Spaho

2012-06-01

87

Evaluación talla estructurada de los stocks de Ensis macha y Tagelus dombeii en el Golfo de Arauco, Chile / Size structured stock assessment of Ensis macha and Tagelus dombeii in the Gulf of Arauco, Chile  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se evaluaron los stocks de Ensis macha y Tagelus dombeii, para la pesquería desarrollada en el Golfo de Arauco, Chile, entre 1996 y 2007. Se utilizó un modelo de evaluación de stock, que consiste en: i) un modelo general de dinámica poblacional especie-específica, ii) modelos para las observaciones [...] de capturas anuales, composición por tamaños y captura por unidad de esfuerzo; iii) funciones de log-verosimilitud para cada segmento de información y penalizaciones y; iv) un proceso de estimación numérica. El proceso de estimación permite la determinación simultánea de los parámetros poblacionales, tales como los parámetros de crecimiento de von Bertalanffy, la tasa de mortalidad natural a la edad, tasas de mortalidad por pesca, selectividad, y reclutamientos. Para E. macha se indican síntomas claros de sobreexplotación entre los años 1996 y 2007, con una condición de stock desovante y reclutamientos crítica y una estructura de tamaños y edades en los desembarques que dan cuenta de selectividades inferiores a la talla de primera madurez. Para el caso de T. dombeii, también se detectan algunos síntomas de sobreexplotación, con una condición de stock desovante y reclutamientos más saludable que la observada en el caso de E. macha, pero con una estructura de tamaños y edades en los desembarques que evidencian una alta dependencia de los reclutamientos anuales para el éxito de la actividad. Los stocks parentales de ambas especies muestran tendencias descendentes marcadas, lo cual a su vez estaría afectando de manera importante los reclutamientos a la pesquería. A la luz de los resultados es evidente que en el caso de las pesquerías de huepo y navajuela del Golfo de Arauco es prioritario disminuir el esfuerzo de pesca y mejorar la selectividad en la extracción. En caso que no se realicen cambios en este sentido la sustentabilidad de estas pesquerías puede verse seriamente comprometida. Abstract in english A stock assessment of Ensis macha and Tagelus dombeii for the fishery within the Gulf of Arauco, Chile was conducted from 1996 to 2007. The stock assessment model consisted of: (i) a general model of species-specific population dynamics, ii) models for the observations of annual catches, size compos [...] ition and catch per unit effort; iii) log-likelihood functions for each segment of information and penalties, and iv) a numerical estimation process. The estimation process allows the simultaneous determination of population parameters such as von Bertalanffy growth parameters, rate of natural mortality at age, fishing mortality rates, selectivity, and recruitment. The results for E. macha show clear signs of overfishing between 1996 and 2007, with a critical condition existing in regards to spawning stock and recruitment; the size and age structure in the landings indicates fishing activities are selecting fish that are smaller than the size at first maturity. In the case of T. dombeii, some signs of over exploitation are also detected but with spawning stock and recruitments healthier than that observed in the case of E. macha. Nevertheless, the size and age structure of the landings shows high dependence on the annual recruitment for the success of the fishery. The parental stocks of both species show clear declining trends, which is strongly affecting recruitments to the fishery. Our results demonstrate that it is critical to decrease the amount of fishing and improve the selectivity of the fishery. If changes towards this direction are not carried out, the sustainability of these fisheries is under threat.

Aldo F, Hernández; Luis A, Cubillos; Renato A, Quiñones.

88

Evaluación talla estructurada de los stocks de Ensis macha y Tagelus dombeii en el Golfo de Arauco, Chile / Size structured stock assessment of Ensis macha and Tagelus dombeii in the Gulf of Arauco, Chile  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se evaluaron los stocks de Ensis macha y Tagelus dombeii, para la pesquería desarrollada en el Golfo de Arauco, Chile, entre 1996 y 2007. Se utilizó un modelo de evaluación de stock, que consiste en: i) un modelo general de dinámica poblacional especie-específica, ii) modelos para las observaciones [...] de capturas anuales, composición por tamaños y captura por unidad de esfuerzo; iii) funciones de log-verosimilitud para cada segmento de información y penalizaciones y; iv) un proceso de estimación numérica. El proceso de estimación permite la determinación simultánea de los parámetros poblacionales, tales como los parámetros de crecimiento de von Bertalanffy, la tasa de mortalidad natural a la edad, tasas de mortalidad por pesca, selectividad, y reclutamientos. Para E. macha se indican síntomas claros de sobreexplotación entre los años 1996 y 2007, con una condición de stock desovante y reclutamientos crítica y una estructura de tamaños y edades en los desembarques que dan cuenta de selectividades inferiores a la talla de primera madurez. Para el caso de T. dombeii, también se detectan algunos síntomas de sobreexplotación, con una condición de stock desovante y reclutamientos más saludable que la observada en el caso de E. macha, pero con una estructura de tamaños y edades en los desembarques que evidencian una alta dependencia de los reclutamientos anuales para el éxito de la actividad. Los stocks parentales de ambas especies muestran tendencias descendentes marcadas, lo cual a su vez estaría afectando de manera importante los reclutamientos a la pesquería. A la luz de los resultados es evidente que en el caso de las pesquerías de huepo y navajuela del Golfo de Arauco es prioritario disminuir el esfuerzo de pesca y mejorar la selectividad en la extracción. En caso que no se realicen cambios en este sentido la sustentabilidad de estas pesquerías puede verse seriamente comprometida. Abstract in english A stock assessment of Ensis macha and Tagelus dombeii for the fishery within the Gulf of Arauco, Chile was conducted from 1996 to 2007. The stock assessment model consisted of: (i) a general model of species-specific population dynamics, ii) models for the observations of annual catches, size compos [...] ition and catch per unit effort; iii) log-likelihood functions for each segment of information and penalties, and iv) a numerical estimation process. The estimation process allows the simultaneous determination of population parameters such as von Bertalanffy growth parameters, rate of natural mortality at age, fishing mortality rates, selectivity, and recruitment. The results for E. macha show clear signs of overfishing between 1996 and 2007, with a critical condition existing in regards to spawning stock and recruitment; the size and age structure in the landings indicates fishing activities are selecting fish that are smaller than the size at first maturity. In the case of T. dombeii, some signs of over exploitation are also detected but with spawning stock and recruitments healthier than that observed in the case of E. macha. Nevertheless, the size and age structure of the landings shows high dependence on the annual recruitment for the success of the fishery. The parental stocks of both species show clear declining trends, which is strongly affecting recruitments to the fishery. Our results demonstrate that it is critical to decrease the amount of fishing and improve the selectivity of the fishery. If changes towards this direction are not carried out, the sustainability of these fisheries is under threat.

Aldo F, Hernández; Luis A, Cubillos; Renato A, Quiñones.

2011-08-01

89

77 FR 29969 - Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...stock including, if appropriate, oil and gas-related activities...estimates are outdated for harbor, harp, and gray seals. The sections on other mortality...2005-2009, there were 7 harbor seals, 3 harp seals, 1 gray seal, 1 hooded...

2012-05-21

90

Population Dynamics and Stock Assessment of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758 in the Coastal Area of Trang Province, Thailand  

Directory of Open Access Journals (Sweden)

Full Text Available The population dynamics and stock assessment of blue swimming crab (Portunus pelagicus Linnaeus, 1758 in the coastal area of Trang province, Southern Thailand was done through stratified sampling of 7,499 crabs that were caught by crab gill nets and crab traps. The sampling was done from September 2006 to August 2007. The carapace width and weight relationship was measured, including parameters such as asymptotic outer carapace width (OCWa, curvature (K, asymptotic inner carapace width (ICWa, total mortality coefficient (Z, natural mortality coefficient (M, fishing mortality coefficient (F, exploitation rate (E, and total stock at first catch (Lc. The maximum sustainable yield (MSY, maximum economic yield (MEY and total biomass (B were estimated. Results showed that the asymptotic outer carapace width was 17.30. The asymptotic inner carapace width was 16.70 cm and its curvature was 1.5 per year. The total mortality coefficient was 8.96 per year, natural mortality coefficient was 1.61 per year and fishing mortality coefficient was 7.35 per year. The exploitation rate was 0.82. The total stock of blue swimming crab at first catch  at 2.5 - 3.0 cm was 7,895,170 individuals. Results of stock assessment also showed that the maximum sustainable yield was 364.33 tons, maximum economic yield was 25.29 million Baht (1 Baht = US$ 33 and total biomass was 139.83 MT. A 40 % decrease in the level of fishing effort is recommended to ensure sustainability of the blue swimming crab stock.

Amonsak SAWUSDEE

2009-06-01

91

Evidence of segregated spawning in a single marine fish stock: Sympatric divergence of ecotypes in icelandic cod?  

Science.gov (United States)

There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ???1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes.

Grabowski, T.B.; Thorsteinsson, V.; McAdam, B.J.; Marteinsdottir, G.

2011-01-01

92

Impact Assessment of the Role of Nigerian Stock Exchange on the Economic Development of Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available The stock exchange is a specialized market for the buying and selling of securities. These securities include stocks and shares which represent ownership interests in business, debentures and government bonds. The study assessed the impact that the Nigerian stock exchange has created on the development of the Nigerian economy. To achieve the objectives, this study reviewed stock exchange, its functions, activities, roles, and legislation. The advantages and disadvantages of listing on the stock market were also x-rayed. Also highlighted were the trading, clearing and settlement process of the Nigerian stock exchange and the short comings. The study concluded that for the Nigerian stock exchange to contribute significantly in the development of the Nigerian economy through mobilization and utilization of funds for expansion of business enterprises in the country, it should intensify efforts in creating public awareness as regards its services to the economy, effective investor education, fostering and stimulating speculation in the market and reforms that would compel investors to take due diligence when funds are to be raised by government to eliminate the buying and selling culture that exists in the market should be carried out.

Okoh, Lucky

2011-04-01

93

Welfare aspects of stocking density in farmed rainbow trout, assessed by behavioural and physiological methods  

DEFF Research Database (Denmark)

There is an increasing amount of interest in the welfare of fish from aquaculture. There are several aquaculture practices that may act as chronic stressors and therefore have the potential to negatively impact welfare. Stocking density has been highlighted as a particular welfare concern, from both an ethical and practical point of view. A quantity of research has been conducted on the relationship between stocking density and indicators of welfare in farmed rainbow trout Oncorhynchus mykiss. The studies to date have revealed that both low and high densities have the potential to detrimentally affect welfare in rainbow trout. Several studies have endeavoured to make specific recommendations for maximum stocking density limits for rainbow trout. However, wide discrepancies exist, highlighting the fact that it has been a challenge to identify density limits that promote optimal welfare and production in rainbow trout. This emphasises the significance of developing alternative methods that provide insight into the potential density limits that are optimal for welfare and performance in rainbow trout. Here, a behavioural method using two-tank systems was developed and applied. The twotank systems consisted of two identical tanks which were attached to each other with a doorway allowing the fish to move freely between the two tanks. By studying the spatial distribution of fish in two-tank systems stocked with different densities and the neuroendocrine stress levels of the fish, a density level was established that showed indications of crowding. The results revealed that a level of aversion to crowding had been reached at an absolute density of approximately 140 kg m–3. Additionally, the influence of the established density limit on physiological indicators of welfare and performance were investigated. At this density of 140 kg m–3, the lower oxygen consumption rates and lower quantity of scale loss collected from the tanks suggested reduced levels of social hierarchy related aggressive encounters. Higher brain serotonergic activity in the brain stem of individuals held at this density indicated elevated stress levels, despite low concentrations of plasma cortisol. The reduced energetic expenditure at 140 kg m–3 resulted in a better utilisation of ingested feed and hence growth performance. Taken together, despite the chronic stress levels at this density, the results showed that at this density the reduced energy expenditure, attributed to reduced aggressive social interactions, resulted in a better growth performance. Therefore, it may be concluded that application of the method using the two-tank systems provided new insight into an optimal stocking density limit for rainbow trout. Furthermore, the method presented here provides a promising tool for investigating stocking density levels in rainbow trout. Further development of the current method would consider it applicable for determining limits for a range of culture situations.

Laursen, Danielle Caroline

2013-01-01

94

Robustness of egg production methods as a fishery independent alternative to assess the Eastern Baltic cod stock (Gadus morhua callarias L.)  

DEFF Research Database (Denmark)

At present, several cod stocks are outside safe biological limits and are managed under recovery plans. For these stocks Total Allowable Catches (TAC's) are generally low and quotas are accompanied by a broad variety of technical measures influencing the fishing patterns. Consequently, the input data to stock assessment models relying on catch statistics from the commercial fisheries is potentially biased and the perception of stock status may be incorrect. Egg production methods (EPM) provide a fishery independent alternative. Additionally, they provide better estimates of stock reproductive potential (SRP). Eastern Baltic cod (Gad us morhua callarias L) has severely declined throughout the 2nd half of the 1980s and 1st half of the 1990s due to climate-driven adverse hydrographic conditions and high fishing intensity. Since 2007 the stock is managed under a long-term management plan and showed signs of recovery in most recent years. Since 1986. egg surveys have been carried! out regularly in the Bornholm Basin, the most important spawning area of Eastern Baltic cod since mid-1980s. In the present paper the robustness of EPM towards simplification of spawning parameters and toward; reduction of the number of egg surveys is tested applying three different methods requiring different numbers of egg surveys. We applied the annual egg production method (AEPM) requiring full egg survey coverage of the spawning season to estimate cod abundances in the Bornholm Basin. In addition, the daily fecundity reduction method (DFRM) and the daily egg production method (DEPM) were tested, the latter two methods requiring only single egg surveys, but require more complex reproduction input parameters. All three methods provided a comparable result, which was also expected as many spawning parameters were derived from the same underlying data sets. In a sensitivity analysis several input parameters were varied simultaneously up to 20% in both directions. EPM were! especially sensitive towards change.; in proportions of matur! e female s at age, whereas changes in the various fecundity parameters and spawning fraction were less influential. EPM results followed the large scale spawning stock trends of the Baltic International Trawl Survey index, whereas the year to year variations of the index were not captured to well. EPM yielded spawning stock sizes in the same order of magnitude as provided by a spatially down-scaled multi-species stock assessment model

Tomkiewicz, Jonna; Köster, Fritz

2012-01-01

95

The Stock Book 2008  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2008-01-01

96

The Stock Book 2009  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2009-01-01

97

The Stock Book 2005  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2005-01-01

98

The Stock Book 2000  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2000-01-01

99

The Stock Book 2003  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2003-01-01

100

The Stock Book 2004  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2004-01-01

 
 
 
 
101

The Stock Book 2002  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2002-01-01

102

The Stock Book 2001  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2001-01-01

103

The Stock Book 2006  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2003-01-01

104

The Stock Book 2007  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2007-01-01

105

The Stock Book 2010  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Stock Book is the principal annual publication of the Marine Institute's Fisheries Science Services (FSS). Its purpose is to provide the latest impartial scientific advice on the commercially exploited fish stocks of interest to Ireland.

Institute, Marine

2011-01-01

106

Potential Conflict between Fishermen and Giant Otter (Pteronura brasiliensis) Populations by Fishermen in Response to Declining Stocks of Arowana Fish (Osteoglossum bicirrhosum) in Northeastern Peru  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giant otter (Pteronura brasiliensis) populations are increasing in many parts of the Peruvian Amazon, and are coming into contact with people more regularly. Giant otters are piscivores and fishermen often see them as potential competitors for fish stocks. We report on giant otter - fisherman conflict on the River Yanayacu. During informal discussions, we found that fishermen considered the giant otter a competitor for fish, and one of their main concerns was for the fisheries of arowana (Ost...

Maribel Recharte; Mark Bowler; Richard Bodmer

2008-01-01

107

Defining, assessing and promoting the welfare of farmed fish.  

Science.gov (United States)

As currently practised, the culture of fish for food potentially raises concerns about the welfare of farmed fish, and this is a topic that has received considerable attention. As vertebrates, fish share a number of features with the birds and mammals that are more commonly farmed, so many welfare principles derived from consideration of these groups may also be applied to fish. However, fish have a long, separate evolutionary history and are also adapted to a very different, aquatic environment. For these reasons, they have a number of special features that are relevant to how welfare is defined, assessed and promoted and these are discussed. The various methods that are available to researchers for identifying and assessing good and bad welfare in fish are considered, including assessment of physical health and physiological, behavioural and genomic status. The subset of practical welfare indicators that can be used on working farms is also reviewed. Various aspects of intensive aquaculture that can potentially compromise fish welfare are outlined, as are some strategies available for mitigating such adverse effects. Finally, the paper ends by looking briefly to the future, identifying likely changes in aquaculture practices and how these might affect the welfare of farmed fish. PMID:25000796

Huntingford, F A; Kadri, S

2014-04-01

108

Indirect manifestation of cormorant (Phalacrocorax carbo sinensis (L. predation on pond fish stock  

Directory of Open Access Journals (Sweden)

Full Text Available The damage to fisheries caused by cormorant predation pressure consists of losses due to direct predation and subsequent indirect losses elicited by cormorant feeding activities resulting in fish wounding and stress. Healed wounds reduce the commercial value of afflicted fish and stress may impact fish body and health condition. Fulton´s condition coefficient (FCC was calculated for wounded and healthy two-year old carp originating from five South Moravian (Czech Republic fishponds. Significant (P = 0.0011 differences in FCC (mean ± s.d., were found between non-wounded (1.48 ± 0.11, n = 19 and wounded mirror common carp, Cyprinus carpio (1.33 ± 0.14, n = 19. However no differences (P > 0.05 were recorded in scaly common carp between non-wounded (FCC 1.41 ± 0.25, n = 33 and wounded (FCC 1.46 ± 0.47, n = 33 fish of the same age and size category. A computer assisted image analysis was applied to describe the extent of such injuries. In the case of two-year old mirror, scaly and bighead carp (Aristichthys nobilis, signs of serious injuries (necroses were recorded on 1.93, 0.89 and 1.61% of body surface, respectively. Fish with deep wounds and scars, often accompanied with progressive necroses, were subject to parasitological examination. The percentage of wounded fish from total fish harvested was evaluated as ranging between < 1 and 47.4% in five ponds under study.

Kortan J.

2008-10-01

109

Mapping of soil organic carbon stocks for spatially explicit assessments of climate change mitigation potential  

International Nuclear Information System (INIS)

Current methods for assessing soil organic carbon (SOC) stocks are generally not well suited for understanding variations in SOC stocks in landscapes. This is due to the tedious and time-consuming nature of the sampling methods most commonly used to collect bulk density cores, which limits repeatability across large areas, particularly where information is needed on the spatial dynamics of SOC stocks at scales relevant to management and for spatially explicit targeting of climate change mitigation options. In the current study, approaches were explored for (i) field-based estimates of SOC stocks and (ii) mapping of SOC stocks at moderate to high resolution on the basis of data from four widely contrasting ecosystems in East Africa. Estimated SOC stocks for 0–30 cm depth varied both within and between sites, with site averages ranging from 2 to 8 kg m?2. The differences in SOC stocks were determined in part by rainfall, but more importantly by sand content. Results also indicate that managing soil erosion is a key strategy for reducing SOC loss and hence in mitigation of climate change in these landscapes. Further, maps were developed on the basis of satellite image reflectance data with multiple R-squared values of 0.65 for the independent validation data set, showing variations in SOC stocks across these landscapes. These maps allow for spatially explicit targeting of potential climate change mitigation efforts through soil carbon sequestration, which is one option for climate change mitigation and adaptation. Further, the maps can be used to monitor the impacts of such mitigation efforts over time. (letter)

110

How systematic age underestimation can impede understanding of fish population dynamics: Lessons learned from a Lake Superior cisco stock  

Science.gov (United States)

Systematic underestimation of fish age can impede understanding of recruitment variability and adaptive strategies (like longevity) and can bias estimates of survivorship. We suspected that previous estimates of annual survival (S; range = 0.20-0.44) for Lake Superior ciscoes Coregonus artedi developed from scale ages were biased low. To test this hypothesis, we estimated the total instantaneous mortality rate of adult ciscoes from the Thunder Bay, Ontario, stock by use of cohort-based catch curves developed from commercial gill-net catches and otolith-aged fish. Mean S based on otolith ages was greater for adult females (0.80) than for adult males (0.75), but these differences were not significant. Applying the results of a study of agreement between scale and otolith ages, we modeled a scale age for each otolith-aged fish to reconstruct catch curves. Using modeled scale ages, estimates of S (0.42 for females, 0.36 for males) were comparable with those reported in past studies. We conducted a November 2005 acoustic and midwater trawl survey to estimate the abundance of ciscoes when the fish were being harvested for roe. Estimated exploitation rates were 0.085 for females and 0.025 for males, and the instantaneous rates of fishing mortality were 0.089 for females and 0.025 for males. The instantaneous rates of natural mortality were 0.131 and 0.265 for females and males, respectively. Using otolith ages, we found that strong year-classes at large during November 2005 were caught in high numbers as age-1 fish in previous annual bottom trawl surveys, whereas weak or absent year-classes were not. For decades, large-scale fisheries on the Great Lakes were allowed to operate because ciscoes were assumed to be short lived and to have regular recruitment. We postulate that the collapse of these fisheries was linked in part to a misunderstanding of cisco biology driven by scale-ageing error. ?? Copyright by the American Fisheries Society 2008.

Yule, D.L.; Stockwell, J.D.; Black, J.A.; Cullis, K.I.; Cholwek, G.A.; Myers, J.T.

2008-01-01

111

Assessing soil carbon stocks under pastures through orbital remote sensing  

Directory of Open Access Journals (Sweden)

Full Text Available The growing demand of world food and energy supply increases the threat of global warming due to higher greenhouse gas emissions by agricultural activity. Therefore, it is widely admitted that agriculture must establish a new paradigm in terms of environmental sustainability that incorporate techniques for mitigation of greenhouse gas emissions. This article addresses to the scientific demand to estimate in a fast and inexpensive manner current and potential soil organic carbon (SOC stocks in degraded pastures, using remote sensing techniques. Four pastures on sandy soils under Brazilian Cerrado vegetation in São Paulo state were chosen due to their SOC sequestration potential, which was characterized for the soil depth 0-50 cm. Subsequently, a linear regression analysis was performed between SOC and Leaf Area Index (LAI measured in the field (LAIfield and derived by satellite (LAIsatellite as well as SOC and pasture reflectance in six spectra from 450 nm - 2350 nm, using the Enhanced Thematic Mapper (ETM+ sensor of satellite Landsat 7. A high correlation between SOC and LAIfield (R² = 0.9804 and LAIsatellite (R² = 0.9812 was verified. The suitability of satellite derived LAI for SOC determination leads to the assumption, that orbital remote sensing is a very promising SOC estimation technique from regional to global scale.

Gabor Gyula Julius Szakács

2011-10-01

112

Assessing soil carbon stocks under pastures through orbital remote sensing  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The growing demand of world food and energy supply increases the threat of global warming due to higher greenhouse gas emissions by agricultural activity. Therefore, it is widely admitted that agriculture must establish a new paradigm in terms of environmental sustainability that incorporate techniq [...] ues for mitigation of greenhouse gas emissions. This article addresses to the scientific demand to estimate in a fast and inexpensive manner current and potential soil organic carbon (SOC) stocks in degraded pastures, using remote sensing techniques. Four pastures on sandy soils under Brazilian Cerrado vegetation in São Paulo state were chosen due to their SOC sequestration potential, which was characterized for the soil depth 0-50 cm. Subsequently, a linear regression analysis was performed between SOC and Leaf Area Index (LAI) measured in the field (LAIfield) and derived by satellite (LAIsatellite) as well as SOC and pasture reflectance in six spectra from 450 nm - 2350 nm, using the Enhanced Thematic Mapper (ETM+) sensor of satellite Landsat 7. A high correlation between SOC and LAIfield (R² = 0.9804) and LAIsatellite (R² = 0.9812) was verified. The suitability of satellite derived LAI for SOC determination leads to the assumption, that orbital remote sensing is a very promising SOC estimation technique from regional to global scale.

Gabor Gyula Julius, Szakács; Carlos Clemente, Cerri; Uwe, Herpin; Martial, Bernoux.

113

Assessing soil carbon stocks under pastures through orbital remote sensing  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The growing demand of world food and energy supply increases the threat of global warming due to higher greenhouse gas emissions by agricultural activity. Therefore, it is widely admitted that agriculture must establish a new paradigm in terms of environmental sustainability that incorporate techniq [...] ues for mitigation of greenhouse gas emissions. This article addresses to the scientific demand to estimate in a fast and inexpensive manner current and potential soil organic carbon (SOC) stocks in degraded pastures, using remote sensing techniques. Four pastures on sandy soils under Brazilian Cerrado vegetation in São Paulo state were chosen due to their SOC sequestration potential, which was characterized for the soil depth 0-50 cm. Subsequently, a linear regression analysis was performed between SOC and Leaf Area Index (LAI) measured in the field (LAIfield) and derived by satellite (LAIsatellite) as well as SOC and pasture reflectance in six spectra from 450 nm - 2350 nm, using the Enhanced Thematic Mapper (ETM+) sensor of satellite Landsat 7. A high correlation between SOC and LAIfield (R² = 0.9804) and LAIsatellite (R² = 0.9812) was verified. The suitability of satellite derived LAI for SOC determination leads to the assumption, that orbital remote sensing is a very promising SOC estimation technique from regional to global scale.

Gabor Gyula Julius, Szakács; Carlos Clemente, Cerri; Uwe, Herpin; Martial, Bernoux.

2011-10-01

114

Complex dynamics analysis on fish stock harvested by two players with heterogeneous rationality  

International Nuclear Information System (INIS)

This paper formulates a duopoly game model with heterogeneous expectations assuming that two players with asymmetric information harvest fish from a common fish ground and sell it in an imperfectly competitive market. We study the existence and stability of this system's positive equilibrium characterizing the sustainable use of the renewable resource. Then show the complex dynamics of this system in different parameters though numerical simulation. We finally show the influence of the adjustment speed of the harvesting quantity on the set of initial conditions which give non-negative trajectories converging to an equilibrium (called as a feasible set). When the player accelerates the adjustment speed in order to achieve initial advantage, we discover that it leads to instability of system and makes the system sink into the chaotic state and thus makes the resources exhaust more easily.

115

Complex dynamics analysis on fish stock harvested by two players with heterogeneous rationality  

Energy Technology Data Exchange (ETDEWEB)

This paper formulates a duopoly game model with heterogeneous expectations assuming that two players with asymmetric information harvest fish from a common fish ground and sell it in an imperfectly competitive market. We study the existence and stability of this system's positive equilibrium characterizing the sustainable use of the renewable resource. Then show the complex dynamics of this system in different parameters though numerical simulation. We finally show the influence of the adjustment speed of the harvesting quantity on the set of initial conditions which give non-negative trajectories converging to an equilibrium (called as a feasible set). When the player accelerates the adjustment speed in order to achieve initial advantage, we discover that it leads to instability of system and makes the system sink into the chaotic state and thus makes the resources exhaust more easily.

Gu Enguo [Department of Mathematics, South-Central University for Nationalities, Wuhan 430074 (China)], E-mail: guenguo@163.com

2009-10-30

116

Kootenai River Resident Fish Assessment, FY2008 KTOI Progress Report.  

Energy Technology Data Exchange (ETDEWEB)

The overarching goal of project 1994-049-00 is to recover a productive, healthy and biologically diverse Kootenai River ecosystem, with emphasis on native fish species rehabilitation. It is especially designed to aid the recovery of important fish stocks, i.e. white sturgeon, burbot, bull trout, kokanee and several other salmonids important to the Kootenai Tribe of Idaho and regional sport-fisheries. The objectives of the project have been to address factors limiting key fish species within an ecosystem perspective. Major objectives include: establishment of a comprehensive and thorough biomonitoring program, investigate ecosystem--level in-river productivity, test the feasibility of a large-scale Kootenai River nutrient addition experiment (completed), to evaluate and rehabilitate key Kootenai River tributaries important to the health of the lower Kootenai River ecosystem, to provide funding for Canadian implementation of nutrient addition and monitoring in the Kootenai River ecosystem (Kootenay Lake) due to lost system productivity created by construction and operation of Libby Dam, mitigate the cost of monitoring nutrient additions in Arrow Lakes due to lost system productivity created by the Libby-Arrow water swap, provide written summaries of all research and activities of the project, and, hold a yearly workshop to convene with other agencies and institutions to discuss management, research, and monitoring strategies for this project and to provide a forum to coordinate and disseminate data with other projects involved in the Kootenai River basin.

Holderman, Charles

2009-06-26

117

Geomatics and bioenergy feasibility assessments: Taking stock and looking forward  

Energy Technology Data Exchange (ETDEWEB)

Renewable energy resources are spatially distributed, and their potential to contribute to societal energy supplies is dependent on local geographic nuances. To provide relevant and robust baseline information, these spatial qualities must be considered when assessing resource availability or technology performance. This is the impetus behind the application of geomatics in the field of renewable energy. Given that each renewable energy source option has unique geographic qualities, a one-size-fits-all analytical approach is not possible. It is thus important to examine how the geographic qualities of specific renewable energy options are managed in the methodological approaches that are used to assess them. To this end, this paper reviews the ways in which geomatics has been used to provide geographic information about bioenergy feasibility, and to solve fundamental bioenergy measurement problems in terms of distinguishing actual from potential feedstock, quantifying multiple biomass supply options, and assessing the scope of conversion platforms. Particular attention is given to data quality, the commensurability of data models and the energy sources they attempt to visualize and analyze, the methods used for facility location decisions, and the capacity to perform site-specific analyses of technology performance. The paper also discusses the ways that the 'static' nature of geographic information can be overcome to take seriously the temporal issues that are related to bioenergy feasibility. Moving forward, bioenergy assessments must begin with a comprehensive resource assessment and consider a range of conversion options. This baseline information will enable bioenergy to be taken seriously in energy investment decisions. (author)

Calvert, K. [Department of Geography, Faculty of Arts and Science, Queen' s University, Queen' s Institute for Energy and Environmental Policy, Macintosh Corry Hall - Room E104B, 138 Union Street, Kingston, Ontario (Canada)

2011-02-15

118

A framework for assessing global change risks to forest carbon stocks in the United States.  

Science.gov (United States)

Among terrestrial environments, forests are not only the largest long-term sink of atmospheric carbon (C), but are also susceptible to global change themselves, with potential consequences including alterations of C cycles and potential C emission. To inform global change risk assessment of forest C across large spatial/temporal scales, this study constructed and evaluated a basic risk framework which combined the magnitude of C stocks and their associated probability of stock change in the context of global change across the US. For the purposes of this analysis, forest C was divided into five pools, two live (aboveground and belowground biomass) and three dead (dead wood, soil organic matter, and forest floor) with a risk framework parameterized using the US's national greenhouse gas inventory and associated forest inventory data across current and projected future Köppen-Geiger climate zones (A1F1 scenario). Results suggest that an initial forest C risk matrix may be constructed to focus attention on short- and long-term risks to forest C stocks (as opposed to implementation in decision making) using inventory-based estimates of total stocks and associated estimates of variability (i.e., coefficient of variation) among climate zones. The empirical parameterization of such a risk matrix highlighted numerous knowledge gaps: 1) robust measures of the likelihood of forest C stock change under climate change scenarios, 2) projections of forest C stocks given unforeseen socioeconomic conditions (i.e., land-use change), and 3) appropriate social responses to global change events for which there is no contemporary climate/disturbance analog (e.g., severe droughts in the Lake States). Coupling these current technical/social limits of developing a risk matrix to the biological processes of forest ecosystems (i.e., disturbance events and interaction among diverse forest C pools, potential positive feedbacks, and forest resiliency/recovery) suggests an operational forest C risk matrix remains elusive. PMID:24039889

Woodall, Christopher W; Domke, Grant M; Riley, Karin L; Oswalt, Christopher M; Crocker, Susan J; Yohe, Gary W

2013-01-01

119

Accurate assessment of Congo basin forest carbon stocks requires forest type specific assessments  

Science.gov (United States)

Due to a limited number of field-based studies estimations of carbon stocks in the Central Congo Basin remain highly uncertain. In particular, more information is needed about the variation in stocks between forest types and on the factors explaining these differences. This study presents results from biomass and soil carbon inventories in 46 0.25ha old-growth forest plots located in three study sites in Tshopo District, Democratic Republic of Congo. Four forest community types were identified using cluster and indicator species analysis based on the plots' large tree (>30cm DBH) species composition. Carbon stocks were calculated using newly established forest type specific tree height-diameter relationships to prevent errors related to the use of inappropriate regional relationships from literature. Using the Akaike criterion it became clear that for one site and a few forest types separate tree height-diameter relationships gave a robust and significant better fit, showing that there was a clear and significant interaction effect between sites and forest type. Mean above-ground carbon stocks were estimated at 165 ±44 Mg ha-1. Significant differences were found between forest types, but not between sites for a given forest type. Largest stocks were found in monodominant Gilbertiodendron dewevrei forests (187 ± 37 Mg C ha-1), which occurred in all sites. Smallest stocks (91 ± 14 Mg C ha-1) were found in the Margaritaria discoidea mixed forest type, which occurred only in one site, while two other mixed forest types showed intermediate stocks (148 ± 28 Mg C ha-1 and 160 ± 36 Mg C ha-1 respectively). The observed differences in aboveground stocks between forest types could be explained by forest structure related variables including number of large trees (DBH>70cm), average wood density and dominant height. When comparing the G. dewevrei monodominant type with mixed forest types within each study site, the former showed equal basal area and sometimes higher carbon stocks despite poorer physical and chemical soil properties. Soil organic carbon stocks (0-100cm) did not significantly differ between forest types and were estimated at 109 ± 35 Mg C ha-1. Our results confirm recent findings of significantly lower carbon stocks in the Central Congo Basin as compared to the outer regions and of the importance of local tree height-diameter relationships for accurate carbon stock estimations.

Moonen, Pieter C. J.; Van Ballaert, Siege; Verbist, Bruno; Boyemba, Faustin; Muys, Bart

2014-05-01

120

Potential Conflict between Fishermen and Giant Otter (Pteronura brasiliensis Populations by Fishermen in Response to Declining Stocks of Arowana Fish (Osteoglossum bicirrhosum in Northeastern Peru  

Directory of Open Access Journals (Sweden)

Full Text Available Giant otter (Pteronura brasiliensis populations are increasing in many parts of the Peruvian Amazon, and are coming into contact with people more regularly. Giant otters are piscivores and fishermen often see them as potential competitors for fish stocks. We report on giant otter - fisherman conflict on the River Yanayacu. During informal discussions, we found that fishermen considered the giant otter a competitor for fish, and one of their main concerns was for the fisheries of arowana (Osteoglossum bicirrhosum. This fishery, for young arowanas for sale to the ornamental fish trade, is very important for the communities in the Pacaya-Samiria National Reserve, and fishermen believe that stocks of this species are declining. Although arowana can be preyed upon by giant otter, smaller fish are preferred and there is no evidence for giant otters impacting on populations of this species. We identify a need for more research into giant otter populations, arowana populations, the exploitation of arowana, and the diet of giant otters in northeastern Peru, to support conservation initiatives aimed at changing the perception of giant otters as competitors for fish.

Maribel Recharte

2008-10-01

 
 
 
 
121

Population Dynamics and Stock Assessment of Labeo rohita (Ham., L. calbasu (Ham. and L. gonius (Ham. From the Mymensingh Basin  

Directory of Open Access Journals (Sweden)

Full Text Available Estimated fishing mortality and exploitation values for L. rohita and L. calbasu indicated that their stocks are under heavy fishing pressure. Exploitation values were much higher than the optimum level of 0.5 and remarkably higher than the Emax values. Mean annual catch of L. rohita in 1999 and L. calbasu in both 1998 and 1999 were much higher than their estimated maximum sustainable yield (MSY. Whereas the exploitation values for L. gonius were below the optimum level in 1998 and just at optimum in 1999. The stock of L. gonius is almost under optimum fishing level. Mean annual catch of L. gonius were lower or almost equal to its estimated MSY value in both the years. The Lc/L and M/K values also confirm the above conclusion for L. rohita, L. calbasu and L. gonius.

A. K. Yousuf Haroon

2001-01-01

122

CLI technical commission. Additional safety assessments within the EDF nuclear stock  

International Nuclear Information System (INIS)

This slides presentation addresses additional safety assessments within the EDF nuclear stock. It describes the context and challenges of these assessments (institutional framework, European coherence, major objectives for EDF). It describes how EDF is organised to perform these assessments: a global project after Fukushima, assessments and tests which are beyond the existing safety referential, the three defence lines and their tests. It addresses the content of assessment reports for each topic (earthquake, flooding, loss of water, loss of electric supply, accident management). It indicates some improvements proposed after the first assessments. It describes the improvements concerning the Gravelines power plant. It recalls the assessment agenda, proposes a brief overview of events, comments the results of the third decennial visit of production unit no. 1 which comprised some proof test on the primary circuit, on the reactor vessel and on the reactor building

123

Effects of introduced fish on macroinvertebrate communities in historically fishless headwater and kettle lakes  

Science.gov (United States)

Widespread fish introductions have led to a worldwide decline in the number of fishless lakes and their associated communities. Studies assessing effects of fish stocking on native communities in historically fishless lakes have been limited to high-elevation headwater lakes stocked with non-native trout. Little is known about the effect of fish stocking in historically fishless and hydrologically isolated lowland kettle lakes. We compared the effects of introduced fish on macroinvertebrate communities in kettle lakes stocked with centrarchids, salmonids, and cyprinids, and headwater lakes stocked with brook trout (Salvelinus fontinalis) in Maine, USA. Fish had significant effects on macroinvertebrate community structure in both lake types, with reduced species richness and abundances of taxa characteristic of fishless lakes. The effects of introduced fish were more pronounced in headwater lakes despite a less diverse fish assemblage than in kettle lakes. We attribute this to abundant submerged vegetation providing refuge from fish predation and reduced stocking frequency in kettle lakes. We assessed effects of stocking duration on macroinvertebrates in a subset of headwater lakes with known dates of trout introduction. Species richness and abundance of most taxa declined within 3 years following trout introduction; however, richness and abundance were least in lakes with long stocking histories (???40 years). Macroinvertebrates previously identified as fishless bioindicators were absent from all stocked lakes, indicating that trout rapidly eliminate these sensitive taxa. Conservation of this historically undervalued ecosystem requires protecting remaining fishless lakes and recovering those that have been stocked. ?? 2009 Elsevier Ltd.

Schilling, E.G.; Loftin, C.S.; Huryn, A.D.

2009-01-01

124

Identification and phylogenetic inferences on stocks of sharks affected by the fishing industry off the Northern coast of Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The ongoing decline in abundance and diversity of shark stocks, primarily due to uncontrolled fishery exploitation, is a worldwide problem. An additional problem for the development of conservation and management programmes is the identification of species diversity within a given area, given the mo [...] rphological similarities among shark species, and the typical disembarkation of processed carcasses which are almost impossible to differentiate. The main aim of the present study was to identify those shark species being exploited off northern Brazil, by using the 12S-16S molecular marker. For this, DNA sequences were obtained from 122 specimens collected on the docks and the fish market in Bragança, in the Brazilian state of Pará. We identified at least 11 species. Three-quarters of the specimens collected were either Carcharhinus porosus or Rhizoprionodon sp, while a notable absence was the daggernose shark, Isogomphodon oxyrhyncus, previously one of the most common species in local catches. The study emphasises the value of molecular techniques for the identification of cryptic shark species, and the potential of the 12S-16S marker as a tool for phylogenetic inferences in a study of elasmobranchs.

Luis Fernando da Silva, Rodrigues-Filho; Tainá Carreira da, Rocha; Péricles Sena do, Rêgo; Horacio, Schneider; Iracilda, Sampaio; Marcelo, Vallinoto.

125

Identification and phylogenetic inferences on stocks of sharks affected by the fishing industry off the Northern coast of Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The ongoing decline in abundance and diversity of shark stocks, primarily due to uncontrolled fishery exploitation, is a worldwide problem. An additional problem for the development of conservation and management programmes is the identification of species diversity within a given area, given the morphological similarities among shark species, and the typical disembarkation of processed carcasses which are almost impossible to differentiate. The main aim of the present study was to identify those shark species being exploited off northern Brazil, by using the 12S-16S molecular marker. For this, DNA sequences were obtained from 122 specimens collected on the docks and the fish market in Bragança, in the Brazilian state of Pará. We identified at least 11 species. Three-quarters of the specimens collected were either Carcharhinus porosus or Rhizoprionodon sp, while a notable absence was the daggernose shark, Isogomphodon oxyrhyncus, previously one of the most common species in local catches. The study emphasises the value of molecular techniques for the identification of cryptic shark species, and the potential of the 12S-16S marker as a tool for phylogenetic inferences in a study of elasmobranchs.

Luis Fernando da Silva Rodrigues-Filho

2009-01-01

126

A cost-efficient method to assess carbon stocks in tropical peat soil  

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Full Text Available Estimation of soil carbon stocks in tropical wetlands requires costly laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple yet robust analytical tools to assess soil carbon stocks where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (gC cm?3; Cd as a function of bulk density (g dry soil cm?3; Bd, which can be used to estimate belowground carbon storage using Bd measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (Cd = Bd × 0.49 + 4.61, R2 = 0.96, n = 94 for soils with an organic C content >40%. As organic C content decreases, the relationship between Cd and Bd becomes less predictable as soil texture becomes an important determinant of Cd. The equation predicted soil C stocks to within 0.39% to 7.20% of observed values. When original data were included in the analysis, the revised equation: Cd = Bd × 0.48 + 4.28, R2 = 0.96, n = 678 was well within the 95% confidence intervals of the original equation, and tended to decrease Cd estimates slightly. We recommend this last equation for a rapid estimation of soil C stocks for well developed peat soils where C content >40%.

M. W. Warren

2012-06-01

127

Response of diurnal and nocturnal coral reef fish to protection from fishing: an assessment using baited remote underwater video  

Science.gov (United States)

Diel variation is known to alter the composition and structure of reef fish assemblages. What is unknown is how nocturnal fish assemblages respond to closed fishery area management. Diurnal and nocturnal reef fish assemblages at the Houtman Abrolhos Islands, Western Australia, were studied using baited remote underwater stereo-video systems (stereo-BRUVs). Surveys were conducted during the day and at night (using blue illumination) from three sites inside and three sites outside a closed fishery area (CFA). The relative abundance of 116 fish species from 41 families was recorded. Significant changes were observed in fish assemblage structure from day to night (driven by high dispersion at night) and in areas open versus closed to fishing (driven by increased abundance within the CFA). The effect of protection from fishing was consistent for both diurnal and nocturnal fish assemblages. Closer examination of six targeted fish species showed that their response to diel changes and the absence of fishing pressure varied from species to species. The targeted fishes Pagrus auratus and Glaucosoma hebraicum were sampled during the day and at night with both species responding positively to protection from fishing. Results suggest that the inclusion of diurnal and nocturnal fish assemblage data will provide an improved ability to assess the effectiveness of closed fishery area management.

Harvey, E. S.; Dorman, S. R.; Fitzpatrick, C.; Newman, S. J.; McLean, D. L.

2012-12-01

128

Assessing the state of pelagic fish communities within an ecosystem approach and the European Marine Strategy Framework Directive  

DEFF Research Database (Denmark)

Pelagic fish are key elements in marine foodwebs and thus comprise an important part of overall ecosystem health. We develop a suite of ecological indicators that track pelagic fish community state and evaluate state of specific objectives against Good Environmental Status (GES) criteria. Indicator time-series are calculated for the EU Marine Strategy Framework Directive “Celtic Seas” (CS) and “Greater North Sea” subregions. Precautionary reference points are proposed for each indicator and a simple decision process is then used to aggregate indicators into a GES assessment for each subregion. The pelagic fish communities of both subregions currently appear to be close to GES, but each remains vulnerable. In the CS subregion, fishing mortality is close to the precautionary reference point, although the unknown dynamics of sandeel, sprat, and sardine in the subregion may reduce the robustness of this evaluation. In the North Sea, sandeel stocks have been in poor state until very recently. Pelagic fish community biomass is slightly below the precautionary reference point in both subregions

Shephard, Samuel; Rindorf, Anna

2014-01-01

129

Assessment of current Dutch energy transition policy instruments for the existing housing stock  

Energy Technology Data Exchange (ETDEWEB)

This research assesses to what extent current Dutch energy transition policy instruments for the existing housing stock can fulfil local executive actors' needs and instigate adoption of energy efficiency measures by them. This is done by studying energy policy instruments for the existing housing stock in the Netherlands and in other European countries, and by an empirical research, which analyses barriers and needs of local executive actors. We found that, despite current Dutch energy transition policy instruments for the existing housing stock seem to fulfil local executive actors' needs to a large extent, complementary policy instruments are needed to stimulate and pressure the incumbent renovation regime. A long-term oriented financial rewarding system is needed to build up a structural market for the deployment of renewables, to increase the number of specialist jobs in the building sector, and to stimulate the development of integrated, standardized, building components. Furthermore, a long-term oriented financial rewarding system for energy efficiency investments in housing renovation projects, and a low VAT rate applied to energy efficient renovation measures, are needed. Finally, enforcement possibilities and sanctions (fines) should become an integrative part of Dutch energy certification regulation to make the certificate become part of a value chain. (author)

Tambach, Milly; Hasselaar, Evert; Itard, Laure [Delft University of Technology, OTB Research Institute for Housing, Urban and Mobility Studies, Jaffalaan 9, 2628 BX Delft (Netherlands)

2010-02-15

130

Assessment of current Dutch energy transition policy instruments for the existing housing stock  

International Nuclear Information System (INIS)

This research assesses to what extent current Dutch energy transition policy instruments for the existing housing stock can fulfil local executive actors' needs and instigate adoption of energy efficiency measures by them. This is done by studying energy policy instruments for the existing housing stock in the Netherlands and in other European countries, and by an empirical research, which analyses barriers and needs of local executive actors. We found that, despite current Dutch energy transition policy instruments for the existing housing stock seem to fulfil local executive actors' needs to a large extent, complementary policy instruments are needed to stimulate and pressure the incumbent renovation regime. A long-term oriented financial rewarding system is needed to build up a structural market for the deployment of renewables, to increase the number of specialist jobs in the building sector, and to stimulate the development of integrated, standardized, building components. Furthermore, a long-term oriented financial rewarding system for energy efficiency investments in housing renovation projects, and a low VAT rate applied to energy efficient renovation measures, are needed. Finally, enforcement possibilities and sanctions (fines) should become an integrative part of Dutch energy certification regulation to make the certificate become part of a value chain.

131

Assessment of current Dutch energy transition policy instruments for the existing housing stock  

International Nuclear Information System (INIS)

This research assesses to what extent current Dutch energy transition policy instruments for the existing housing stock can fulfil local executive actors' needs and instigate adoption of energy efficiency measures by them. This is done by studying energy policy instruments for the existing housing stock in the Netherlands and in other European countries, and by an empirical research, which analyses barriers and needs of local executive actors. We found that, despite current Dutch energy transition policy instruments for the existing housing stock seem to fulfil local executive actors' needs to a large extent, complementary policy instruments are needed to stimulate and pressure the incumbent renovation regime. A long-term oriented financial rewarding system is needed to build up a structural market for the deployment of renewables, to increase the number of specialist jobs in the building sector, and to stimulate the development of integrated, standardized, building components. Furthermore, a long-term oriented financial rewarding system for energy efficiency investments in housing renovation projects, and a low VAT rate applied to energy efficient renovation measures, are needed. Finally, enforcement possibilities and sanctions (fines) should become an integrative part of Dutch energy certification regulation to make the certificate become part of a value chain. (author)

132

Geographic variation in Northwest Atlantic fin whale (Balaenoptera physalus) song: implications for stock structure assessment.  

Science.gov (United States)

Passive acoustic data are increasingly being used as a tool for helping to define marine mammal populations and stocks. Fin whale (Balaenoptera physalus) songs present a unique opportunity to determine interstock differences. Their highly stereotyped interpulse interval has been shown to vary between geographic areas and to remain stable over time in some areas. In this study the structure of songs recorded at two geographically close feeding aggregations in the Gulf of St. Lawrence (GSL) and Gulf of Maine (GoM) was compared. Recordings were made from September 2005 through February 2006 in the GSL and intermittently between January 2006 and September 2007 at two locations in the GoM. 6257 pulse intervals corresponding to 19 GSL and 29 GoM songs were measured to characterize songs from both areas. Classification trees showed that GSL songs differ significantly from those in the GoM. The results are consistent with those derived from other stock structure assessment methodologies, such as chemical signature and photoidentification analysis, suggesting that fin whales in these areas may form separate management stocks. Song structure analysis could therefore provide a useful and cost-efficient tool for defining conservation units over temporal and geographical scales relevant to management objectives in fin whales. PMID:19275334

Delarue, Julien; Todd, Sean K; Van Parijs, Sofie M; Di Iorio, Lucia

2009-03-01

133

Assessment of the Greenland Halibut Stock Component in NAFO Subarea 0 + Division 1A offshore + Division 1D-1F  

DEFF Research Database (Denmark)

The paper presents the background and the input parameters from research surveys and the commercial fishery to the assessment of the Greenland halibut stock component in NAFO Subarea 0 + Div. 1A offshore + Div. 1B-1F. During 2006-2009 catches have been around 24,000 tons. Catches increased to 26 900 tons in 2010 and has been at that level since. Survey trawlable biomass in Div. 0B decreased between 2011 and 2013 while biomass and recruitment increases in the Greenland shrimp fish survey and the recruitment of the 2012 year class in the entire survey area was the third largest in the time series. A combined standardized CPUE series from Div. 0A + 1AB has been stable since 2002. A combined CPUE series from Div. 1CD+0B decreased between 2011 and 2012 but increased slightly in 2013 and is above the level in 1990-2004. A combined standardized CPUE series from SA0 and 1 combined has been increasing gradually since 1997 and was in 2013 at the third highest level seen since 1990. CPUE series from the gill net in Div.0A and Div. 0B were close to or at the highest level in the time series.

JØrgensen, Ole A; Treble, M.A.

2014-01-01

134

Fishing for solutions. Environmental and operational assessment of selected Galician fisheries and their products  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fishing is the only hunting activity which is still maintained on an industrial level to sustain worldwide food demand. Currently, worldwide fisheries are suffering a series of hazards linked to overexploitation and increasing human demand for protein, causing a wide range of environmental impacts on marine ecosystems, such as stock depletion or ecosystem disruption. Moreover, the fishing industry has grown to an extent where the environmental burdens associated with on board and on land oper...

Va?zquez Rowe, Ian

2012-01-01

135

Acoustics as a tool for the assessment of Great Lakes forage fishes  

Science.gov (United States)

Sharp reductions in forage fish populations in Lake Michigan have raised concerns about the continued ability of the forage stocks to support large populations of lake trout and other salmonid predators. There was a need for a more comprehensive and accurate estimate of forage fish abundance and distribution to evaluate these concerns. In response, cooperative diel surveys of the Lake Michigan forage species were conducted in late summer 1987 and spring 1989 with acoustics, midwater and bottom trawls.

Argyle, Ray L.

1992-01-01

136

Assessing trade-offs to inform ecosystem-based fisheries management of forage fish  

Science.gov (United States)

Twenty-first century conservation is centered on negotiating trade-offs between the diverse needs of people and the needs of the other species constituting coupled human-natural ecosystems. Marine forage fishes, such as sardines, anchovies, and herring, are a nexus for such trade-offs because they are both central nodes in marine food webs and targeted by fisheries. An important example is Pacific herring, Clupea pallisii in the Northeast Pacific. Herring populations are subject to two distinct fisheries: one that harvests adults and one that harvests spawned eggs. We develop stochastic, age-structured models to assess the interaction between fisheries, herring populations, and the persistence of predators reliant on herring populations. We show that egg- and adult-fishing have asymmetric effects on herring population dynamics - herring stocks can withstand higher levels of egg harvest before becoming depleted. Second, ecosystem thresholds proposed to ensure the persistence of herring predators do not necessarily pose more stringent constraints on fisheries than conventional, fishery driven harvest guidelines. Our approach provides a general template to evaluate ecosystem trade-offs between stage-specific harvest practices in relation to environmental variability, the risk of fishery closures, and the risk of exceeding ecosystem thresholds intended to ensure conservation goals are met. PMID:25407879

Shelton, Andrew Olaf; Samhouri, Jameal F.; Stier, Adrian C.; Levin, Philip S.

2014-01-01

137

Carbon Stock Assessment Using Remote Sensing and Forest Inventory Data in Savannakhet, Lao PDR  

Directory of Open Access Journals (Sweden)

Full Text Available Savannakhet Province, Lao People’s Democratic Republic (PDR, is a small area that is connected to Thailand, other areas of Lao PDR, and Vietnam via road No. 9. This province has been increasingly affected by carbon dioxide (CO2 emitted from the transport corridors that have been developed across the region. To determine the effect of the CO2 increases caused by deforestation and emissions, the total above-ground biomass (AGB and carbon stocks for different land-cover types were assessed. This study estimated the AGB and carbon stocks (t/ha of vegetation and soil using standard sampling techniques and allometric equations. Overall, 81 plots, each measuring 1600 m2, were established to represent samples from dry evergreen forest (DEF, mixed deciduous forest (MDF, dry dipterocarp forest (DDF, disturbed forest (DF, and paddy fields (PFi. In each plot, the diameter at breast height (DBH and height (H of the overstory trees were measured. Soil samples (composite n = 2 were collected at depths of 0–30 cm. Soil carbon was assessed using the soil depth, soil bulk density, and carbon content. Remote sensing (RS; Landsat Thematic Mapper (TM image was used for land-cover classification and development of the AGB estimation model. The relationships between the AGB and RS data (e.g., single TM band, various vegetation indices (VIs, and elevation were investigated using a multiple linear regression analysis. The results of the total carbon stock assessments from the ground data showed that the MDF site had the highest value, followed by the DEF, DDF, DF, and PFi sites. The RS data showed that the MDF site had the highest area coverage, followed by the DDF, PFi, DF, and DEF sites. The results indicated significant relationships between the AGB and RS data. The strongest correlation was found for the PFi site, followed by the MDF, DDF, DEF, and DF sites.

Phutchard Vicharnakorn

2014-06-01

138

ASSESSMENT OF PLASTIC FLOWS AND STOCKS IN SERBIA USING MATERIAL FLOW ANALYSIS  

Directory of Open Access Journals (Sweden)

Full Text Available Material flow analysis (MFA was used to assess the amounts of plastic materials flows and stocks that are annually produced, consumed, imported, exported, collected, recycled, and disposed in the landfills in Serbia. The analysis revealed that approximatelly 269,000 tons of plastic materials are directly disposed in uncontrolled landfills in Serbia without any preatretment, and that siginificant amounts of these materials have already accumulated in the landfills. The substantial amounts of landfilled plastics represent not only a loss of valuable recourses, but also pose a seriuos treath to the environment and human health, and if the trend of direct plastic landfilling is continued, Serbia will face with grave consecequnces.

Goran Vuji?

2010-01-01

139

DISPLACE: a dynamic, individual-based model for spatial fishing planning and effort displacement: Integrating underlying fish population models  

DEFF Research Database (Denmark)

We previously developed a spatially explicit, individual-based model (IBM) evaluating the bio-economic efficiency of fishing vessel movements between regions according to the catching and targeting of different species based on the most recent high resolution spatial fishery data. The main purpose was to test the effects of alternative fishing effort allocation scenarios related to fuel consumption, energy efficiency (value per litre of fuel), sustainable fish stock harvesting, and profitability of the fisheries. The assumption here was constant underlying resource availability. Now, an advanced version couples the vessel model to selected size-based population models and considers the underlying resource dynamics in the distribution and density patterns of the targeted stocks for the cases of Danish and German vessels harvesting the North Sea and Baltic fish stocks. The stochastic fishing process includes direct and local depletion by stock that is specific to the vessel catching power, which is proportionalto the encountered size-based population on the visited ground and is based on stock assessment and research survey data. The impact of the potential fishing effort displacement by vessels on the fish stocks, with resulting fishing mortality, and the vessels’ economic consequences are evaluated on high spatial and seasonal disaggregation levels by simulating different individual choices of vessel speed, fishing grounds and ports. All tested scenarios led to increased overall energy efficiency, except for the fishing closures that increased fuel consumption and costs for most of the vessels due to increased travel distance. On an individual scale, the simulations led to gains and losses due to either the technical interactions between vessels exploiting the same stocks or to the alteration of individual fishing patterns. We demonstrate that integrating the spatial activity of vessels and local fish stock abundance dynamics allow for interactions and more realistic predictions of fishermen behaviour, revenues and stock abundance

Bastardie, Francois; Nielsen, J. Rasmus

140

Assessment of the pelagic fish populations using CEN multi-mesh gillnets: consequences for the characterization of the fish communities  

Directory of Open Access Journals (Sweden)

Full Text Available The contribution of CEN standard pelagic nets to the assessment of fish communities is tested by comparing three metrics (species composition, species abundance, and size structures measured in accordance with the standard (i.e. using benthic nets only to those calculated from the total effort (i.e. including pelagic nets. Hydroacoustic surveys were used simultaneously to assess fish densities in the pelagic habitat. The results show that in most cases the pelagic nets did not provide any extra information about these three metrics. However, their inclusion in the calculation of CPUE and size structures may affect the picture of the fish communities, especially in lakes containing salmonid populations. This study highlights the need to sample pelagic fish when assessing fish communities in order to determine lake quality.

C. Deceliere-Vergès

2008-01-01

 
 
 
 
141

Fish  

Science.gov (United States)

In this project you will learn about different types of fish. In your science journal write what you know about fish. Draw a picture of a common fish you might see where you live. On the handout record the information you learn during this unit. Click here to see the Angel Fish. Record information on Handout #1. Now go to the Clown Fish. ...

Hunter, Ms.

2009-07-07

142

Effect of Different Stocking Ratio of Pangasid Catfish (Pangasius hypophthalmus and Silver Carp (Hypophthalmicthys molitrix on Better Water Quality Maintenance in Cat Fish Farming  

Directory of Open Access Journals (Sweden)

Full Text Available An experiment was conducted in Bangladesh Agricultural University for a period of three and half months from 1st May to 15th August 2002 to observe the effects of different stocking ratio of pangasid catfish and silver carp on better water quality maintenance and impacts of using fence in cat fish farming. Four treatments each with three replicates were used. The fishes were stocked at the rate of 120 fishes/decimal. The stocking ratios were: 100% pangasid catfish in Treatment 1(T1, 0% pangasid catfish plus 50% silver carp in Treatment 2 (T2, 0% pangasid catfish plus 40% silver carp in Treatment 3 (T3 and 50% pangasid catfish plus 50% silver carp in Treatment 4 (T4. Bamboo made fence were used in treatments 2 and 3 to keep the pangasid catfish and silver carp separately along the breadth wise considering the density of each species. Treatment 4 was set without fence. During the period of study, significant differences were found in dissolved oxygen, N03-N and chlorophyll-a concentrations among different stocking ratios of pangasid catfish and silver carp. The highest concentration of P04-P and NO3-N were found in T1 (2.7 and 3.1 mg L-1, respectively followed by treatments T3, T2 and T4. This higher concentration of NO3-N and PO4-P enhanced the plankton biomass especially Cyanophyceae and Euglenophyceae in ponds of treatment 1 and identified dominant bloom forming cyanophytes were Microcystis and Gloeocapsa, which formed the heavy phytoplankton bloom throughout the culture period and deteriorated the water quality in pangasid catfish monoculture ponds (100% pangasid catfish. Whereas better water quality were found in composite culture. Among different stocking ratios, in composite culture 1:1 without fence (treatment 4 gave the best result in better water quality maintenances than 2:1 and 1:1 (with fence, treatment 3 and 2 ratios. In treatment 4 when the nutrients concentrations enhanced the phytoplankton production then silver carp grazed over phytoplankton throughout water body, which prevented the phytoplankton bloom formation during culture period and maintained a better environmental condition. Some algal bloom occurred in the portion of pangasid catfish in treatment 2 and treatment 3. It might be due to the grazing activity of silver carp over phytoplankton was restricted by the fence in those treatments. Considering the above facts composite culture of pangasid catfish and silver carp with 1:1 ratio and without fence may help in maintaining the good environmental condition of catfish farming through preventing the algal bloom.

Zannatul Ferdoushiand Farhana Haque

2006-01-01

143

Improving the assessment and management of the plaice stock complex between the North Sea and the Baltic Sea  

DEFF Research Database (Denmark)

Plaice in Kattegat and Skagerrak have traditionally been considered as one stock unit. However the collected information on biology and fishery in areas between the North and Baltic Seas suggest changes are needed in assessment units as well as in management areas. Plaice in Skagerrak (Division 20) is now considered to be closely associated with plaice in the North Sea and is proposed to be included in the North Sea plaice stock assessment, although it is recognized that local populations are present in the area. Therefore, specific management of the Skagerrak plaice is suggested. Plaice in Kattegat (Division 21), the Belts (Division 22), and the Sound (Division 23) is considered a stock unit and is proposed to be assessed as such. However, separate management by area is also suggested to assure the preservation of the local populations. Plaice in the Baltic (Divisions 24–32) is considered a stock unit and is proposed to be assessed and managed as such. Pragmatic options are suggested for empirical harvest control rules accounting for the dynamic of local abundance, using a survey?based biomass indicator. For the future, new scientific analyses should be developed to better inform the origin of the catches, provided that additional resources are allocated to the annual monitoring of different stocks and components. Such information would provide on?going quantitative information on the degree of mixing of the various components, potentially allowing a more accurate assessment, management, and conservation of the status of these

Ulrich, Clara; Boje, Jesper

2012-01-01

144

Use Limnetic Zooplankton Sampling in Assessments of Fish Community Structure in Minnesota Bass-Panfish Lakes.  

Science.gov (United States)

Zooplankton and fish were sampled in 42 bass-panfish lakes over a two year period to determine if zooplankton sampling coupled with standard fish population assessments could be a useful fisheries management tool. Correlation analysis was used to identify...

J. E. Westerlund, P. C. Jacobson, H. K. Van Offelen, J. K. Hirsch

1998-01-01

145

Risk assessment in stock calf transportation from France to Italy: the contribution of road inspections  

Directory of Open Access Journals (Sweden)

Full Text Available In order to assess the risk associated with the transport of stock calves imported from France to Italy, information obtained from inspections carried out in Piedmont by competent authorities between 2001 and 2010 was considered. The inspections concerned 246 trucks transporting a total of 13,857 fattening calves. Based on the types of infringements recorded, several hazards related to animal welfare, such as overcrowding, tying by the horns and inappropriate mixing, were identified and characterized. The inspection of vehicles revealed hazards concerning partitions, bedding, decks, lighting, drinking and mechanical ventilation systems. A calculation was made of the incidence of these infringements and the consequent exposure of calves to such hazards and risk characterization was performed. The ranking shows overcrowding and the absence of partitions to be major risks in stock calf transportation from France to Italy. A logistic regression was adopted to evaluate the effect on the exposure to hazards of the only two variables recordable during the inspections: number of calves inside each vehicle and distance of the journey. The results showed a direct relationship between the number of calves per vehicle and exposure to overcrowding or to absence of partitions. The journey distance was found weakly and inversely related to exposure to the absence of partitions. The information obtained from the inspections provides not only a basis for evaluating the welfare of calves during transport but also an objective contribution to the assessment of the risks tied to their transportation.

Cesare Zanasi

2012-01-01

146

Fish Passage Assessment: Big Canyon Creek Watershed, Technical Report 2004.  

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of the fish passage assessment as outlined as part of the Protect and Restore the Big Canyon Creek Watershed project as detailed in the CY2003 Statement of Work (SOW). As part of the Northwest Power Planning Council's Columbia Basin Fish and Wildlife Program (FWP), this project is one of Bonneville Power Administration's (BPA) many efforts at off-site mitigation for damage to salmon and steelhead runs, their migration, and wildlife habitat caused by the construction and operation of federal hydroelectric dams on the Columbia River and its tributaries. The proposed restoration activities within the Big Canyon Creek watershed follow the watershed restoration approach mandated by the Fisheries and Watershed Program. Nez Perce Tribal Fisheries/Watershed Program vision focuses on protecting, restoring, and enhancing watersheds and treaty resources within the ceded territory of the Nez Perce Tribe under the Treaty of 1855 with the United States Federal Government. The program uses a holistic approach, which encompasses entire watersheds, ridge top to ridge top, emphasizing all cultural aspects. We strive toward maximizing historic ecosystem productive health, for the restoration of anadromous and resident fish populations. The Nez Perce Tribal Fisheries/Watershed Program (NPTFWP) sponsors the Protect and Restore the Big Canyon Creek Watershed project. The NPTFWP has the authority to allocate funds under the provisions set forth in their contract with BPA. In the state of Idaho vast numbers of relatively small obstructions, such as road culverts, block thousands of miles of habitat suitable for a variety of fish species. To date, most agencies and land managers have not had sufficient, quantifiable data to adequately address these barrier sites. The ultimate objective of this comprehensive inventory and assessment was to identify all barrier crossings within the watershed. The barriers were then prioritized according to the amount of habitat blocked at each site and the fish life history stages impacted. This assessment protocol will hopefully prove useful to other agencies and become a model for use in other watersheds.

Christian, Richard

2004-02-01

147

Application of system dynamics for assessment of changes of the level of stock after introduction of ERP systems  

Directory of Open Access Journals (Sweden)

Full Text Available Application of information management system is an important element of ensuring business effectiveness for any modern enterprise. However, the permanent growth of the cost of such systems requires application of new approaches to assessment of influence of complex information systems upon the level of stock. The article describes a structure of the model and specifically those elements that allow assessment of reduction of delays connected with automation. It offers to assess a change of the stock level with the use of methods of system dynamics. The results are based on imitation experiments of the stock level in the production and sales system with the use of the AnyLogic software system.

Lebedeva Lyudmyla M.

2013-03-01

148

A spatial model approach for assessing windbreak growth and carbon stocks.  

Science.gov (United States)

Agroforestry, the deliberate integration of trees into agricultural operations, sequesters carbon (C) while providing valuable services on agricultural lands. However, methods to quantify present and projected C stocks in these open-grown woody systems are limited. As an initial step to address C accounting in agroforestry systems, a spatial Markov random field model for predicting the natural logarithm (log) of the mean aboveground volume of green ash ( Marsh.) within a shelterbelt, referred to as the log of aboveground volume, was developed using data from an earlier study and web-available soil and climate information. Windbreak characteristics, site, and climate variables were used to model the large-scale trend of the log of aboveground volume. The residuals from this initial model were correlated among sites up to 24 km from a point of interest. Therefore, a spatial dependence parameter was used to incorporate information from sites within 24 km into the prediction of the log of the aboveground volume. Age is an important windbreak characteristic in the model. Thus, the log of aboveground volume can be predicted for a given windbreak age and for values of other explanatory variables associated with a site of interest. Such predictions can be exponentiated to obtain predictions of aboveground volume for windbreaks without repeated inventory. With the capability of quantifying uncertainty, the model has the potential for large regional planning efforts and C stock assessments for many deciduous tree species used in windbreaks and riparian buffers once it is calibrated. PMID:21546670

Hou, Qingjiang; Young, Linda J; Brandle, James R; Schoeneberger, Michele M

2011-01-01

149

Application of the Beck model to stock markets: Value-at-Risk and portfolio risk assessment  

Science.gov (United States)

We apply the Beck model, developed for turbulent systems that exhibit scaling properties, to stock markets. Our study reveals that the Beck model elucidates the properties of stock market returns and is applicable to practical use such as the Value-at-Risk estimation and the portfolio analysis. We perform empirical analysis with daily/intraday data of the S&P500 index return and find that the volatility fluctuation of real markets is well-consistent with the assumptions of the Beck model: The volatility fluctuates at a much larger time scale than the return itself and the inverse of variance, or “inverse temperature”, ? obeys ?-distribution. As predicted by the Beck model, the distribution of returns is well-fitted by q-Gaussian distribution of Tsallis statistics. The evaluation method of Value-at-Risk (VaR), one of the most significant indicators in risk management, is studied for q-Gaussian distribution. Our proposed method enables the VaR evaluation in consideration of tail risk, which is underestimated by the variance-covariance method. A framework of portfolio risk assessment under the existence of tail risk is considered. We propose a multi-asset model with a single volatility fluctuation shared by all assets, named the single ? model, and empirically examine the agreement between the model and an imaginary portfolio with Dow Jones indices. It turns out that the single ? model gives good approximation to portfolios composed of the assets with non-Gaussian and correlated returns.

Kozaki, M.; Sato, A.-H.

2008-02-01

150

Combined effects of high stocking density and Piscirickettsia salmonis treatment on the immune system, metabolism and osmoregulatory responses of the Sub-Antarctic Notothenioid fish Eleginops maclovinus.  

Science.gov (United States)

The aim of this study was to evaluate immunological, metabolic and osmoregulatory secondary stress responses in Eleginops maclovinus specimens submitted to three different stocking densities: i) low (3.1 kg m(-3)), medium (15 kg m(-3)) and high (60 kg m(-3)) during 10 days, alone or in combination with a previous treatment of a protein extract of the pathogen Piscirickettsia salmonis (0.5 ?g g weight body(-1)). Plasma, liver, gill and kidney samples were obtained at the end of both experiments. Plasma cortisol and amino acid levels increased, while plasma glucose, triglyceride and lactate levels decreased at higher stocking densities. However, no effects were observed on serum Immunoglobulin type M (IgM anti P. salmonis level) values. Gill Na(+), K(+)-ATPase activity enhanced under these experimental conditions, suggesting an osmotic imbalance. Energy metabolism changes, assessed by metabolite concentrations and enzyme activities, indicated a reallocation of energetic substrates at higher stocking densities. Specimens inoculated with a protein extract of P. salmonis and maintained at different stocking densities showed primary stress response, as all groups enhanced plasma cortisol concentrations. Serum IgM levels increased after treatment with P. salmonis extract but a negative influence of high stocking density on IgM production was observed when immune system was activated. Furthermore, treatment with P. salmonis protein extract evoked deep changes in the metabolite stores in all tissues tested, indicating a mobilization of energy substrates in response to infection. The results show that stocking density induced immunological, metabolic and osmoregulatory secondary stress responses in E. maclovinus specimens and that previous treatment with P. salmonis compromise these changes. PMID:25108087

Vargas-Chacoff, L; Martínez, D; Oyarzún, R; Nualart, D; Olavarría, V; Yáñez, A; Bertrán, C; Ruiz-Jarabo, I; Mancera, J M

2014-10-01

151

Fish habitat simulation models and integrated assessment tools  

International Nuclear Information System (INIS)

Because of human development water use increases in importance, and this worldwide trend is leading to an increasing number of user conflicts with a strong need for assessment tools to measure the impacts both on the ecosystem and the different users and user groups. The quantitative tools must allow a comparison of alternatives, different user groups, etc., and the tools must be integrated while impact assessments includes different disciplines. Fish species, especially young ones, are indicators of the environmental state of a riverine system and monitoring them is a way to follow environmental changes. The direct and indirect impacts on the ecosystem itself are measured, and impacts on user groups is not included. Fish habitat simulation models are concentrated on, and methods and examples are considered from Norway. Some ideas on integrated modelling tools for impact assessment studies are included. One dimensional hydraulic models are rapidly calibrated and do not require any expert knowledge in hydraulics. Two and three dimensional models require a bit more skilled users, especially if the topography is very heterogeneous. The advantages of using two and three dimensional models include: they do not need any calibration, just validation; they are predictive; and they can be more cost effective than traditional habitat hydraulic models when combined with modern data acquisition systems and tailored in a multi-disciplinary study. Suitable modelling model choice sh study. Suitable modelling model choice should be based on available data and possible data acquisition, available manpower, computer, and software resources, and needed output and accuracy in the output. 58 refs

152

Unraveling biocomplexity of Northeast Atlantic herring stocks using SNP markers  

DEFF Research Database (Denmark)

Atlantic herring (Clupea harengus) exhibit biocomplexity, with widespread, geographically explicit populations that perform long?range migration to common feeding and wintering areas, where they are exploited by fisheries. This means that exploited stocks do not describe discrete units, thereby complicating stock assessment and management. It is therefore of management interest to trace individual population migration patterns and contributions to fisheries. To underpin management and to develop a validated tool for traceability of individuals from mixed?stock samples we applied single nucleotide polymorphism (SNP) markers in Northeast Atlantic herring population samples. Marker panels were targeted to include gene?associated loci to maximize statistical resolution. Application of 281 SNP markers to samples representing different levels of stock complexity showed that the regional origin of individual fish and mixed fish samples could be successfully identified at high statistical power. Our results demonstrate the usefulness of genetic stock identification even in fish, such as herring, exhibiting weak neutral genetic structure, and that such methods allow unprecedented insights into temporal and spatial dynamics applicable to stock assessment methods, as well as presenting a traceability tool for certification of herring and herring products

Bekkevold, Dorte; Limborg, Morten

2012-01-01

153

Estimation of time-varying selectivity in stock assessments using state-space models  

DEFF Research Database (Denmark)

Time-varying selectivity is one of the main challenges in single species age-based assessment models. In classical deterministic VPA-type models the fishing mortality rates are unfiltered representations of the observed catches. As a consequence the selectivity becomes time-varying, but this representation is too fluctuating, because it includes the observation noise. In parametric statistical catch at age models a common assumption is that the selectivity is constant in all years, although time-varying selectivity can be introduced by splitting the data period in blocks with different selectivities, or by using smoothing splines and penalized time-deviances. However, these methods require subjective choices w.r.t. the degree of time-varying allowed. A simple state-space assessment model is presented as an alternative, which among other benefits offers an objective way of estimating time-varying selectivity pattern. The fishing mortality rates are considered (possibly correlated) stochastic processes, and thecorresponding process variances are estimated within the model. The model is applied to North Sea cod and it is verified from simulations that time-varying selectivity can be estimated

Nielsen, Anders; Berg, Casper Willestofte

2014-01-01

154

Assessing patterns of fish demographics and habitat in stream networks  

Science.gov (United States)

Effective habitat restoration planning requires correctly anticipating demographic responses to altered habitats. New applications of Passive Integrated Transponder (PIT) tag technology to fish-habitat research have provided critical insights into fish movement, growth, and surv...

155

Greenland Halibut in Upernavik: a preliminary study of the importance of the stock for the fishing populace : A study undertaken under the Greenland Climate Research Centre  

DEFF Research Database (Denmark)

This report presents research undertaken with the belief that a need exists for better understanding of the social and cultural importance of the Greenland Halibut (Reinhardtius hippoglossoides) fishery to Greenlanders. It was decided the research would focus on one of three coastal Greenland Halibut fishery districts: Upernavik. Upernavik was chosen mgiven the critical importance of Greenland halibut for local fishers and area residents. The best method for presenting a combination of social and fishery data takes the form of a fishery profile. Additionally, given that the government of Greenland is currently in the midst of proposing changes to the Halibut management structure, the report focuses specifically on potential social impacts of the fishery management plan to coastal fishers. The degree and consequence of any impact is a function of the characteristics of the fishing community. The critical point is the vulnerability of the community to negative repercussions of the management action and the resilience the community has in being able to absorb these repercussions. Upernavik and Greenlandic fisheries communities are known to be remote and have limited economic opportunities for residents. Consequently, it is important to understand the adaptability and vulnerability of the community in order to successfully anticipate impacts. Greenland halibut is the most important commercial fish stock for Upernavik residents. In 2010 there were more than 385 fishermen with official licenses for Greenland halibut in Upernavik. There are up to an additional 75 who also fish, however, without paying the license fee. This means that almost half of working age men fish for halibut in the Upernavik district. Fishing is extremely important in Upernavik for its role in the local, mixed economy. Fishing often provides the cash needed for materials needed for work (hunting and fishing equipment such as bullets, nets, snowmobiles, etc.) and daily living (housing, transport, television, food, etc). Fishing also supports the important local cultural practice of meeting social obligations and reciprocity such as through kødgaver (gifting of meat), a practice which remains both culturally and economically important in the smaller settlements. Currently, the government of Greenland is proposing changes to the management of Greenland halibut for the coastal fishers, including the closing the fishery to new entrants in 2012. Additional changes include the introduction of ITQs for large boats. With little discussion of where locals will work and live if they can not earn an income from the fishery, or discussion of how the communities may be impacted by the potential consolidation of quota shares into fewer hands (as is seen in all ITQ fisheries), the report suggests that management follows accepted practices of good governance as it introduces its new Greenland halibut plan. Good governance is participatory and is based upon, among other points, social equity, responsiveness, and transparency. It is also responsive to the present and future needs of society. Since the plan has not yet been implemented, however, there is still time to follow good governance practices for the sustainability of not only the Greenland halibut stock, but also for Greenlandic society.

Hendriksen, Kåre

2012-01-01

156

Genetic diversity of Prochilodus lineatus stocks using in the stocking program of Tietê River, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Objective. Assess the genetic diversity in four brood stocks and one juvenile stock of curimba Prochilodus lineatus in a Hydropower plant in São Paulo - Brazil, using the Tietê River stocking program. Materials and methods. Five RAPD primers were used to amplify the extracted DNA from 150 fin-clip samples. Results. Fifty-nine fragments were polymorphic, 52 had frequencies with significant differences (p<0.05, 45 had low frequencies, 54 were excluded, and two were fixed fragments. High values for polymorphic fragments (71.19% to 91.53% and Shannon index (0.327 to 0.428 were observed. The genetic divergence values within each stock were greater than 50%. Most of the genetic variation was found within the groups through the AMOVA analysis, which was confirmed by the results of the identity and genetic distance. High ancestry levels (FST among the groups value indicated high and moderate genetic differentiation. The estimates of number of migrants by generation (Nm indicated low levels of gene flow. High and moderate genetic divergence between groups (0.58 to 0.83 was observed. Conclusions. The results indicate high variability within the stocks, and genetic differentiation among them. The fish stocks analyzed represent a large genetic base that will allow the fish technicians to release juveniles without genetic risks to wild populations present in the river. These genetic procedures may be used as models for other migratory species, including those threatened by extinction.

Ricardo Ribeiro

2013-11-01

157

Loss of genetic variability at the transferrin locus in five hatchery stocks of tambaqui (Colossoma macropomum  

Directory of Open Access Journals (Sweden)

Full Text Available Knowledge and conservation of the genetic variability in stocks maintained as live gene banks have become a high priority task for Brazilian fish culture. The aim of the present survey was to assess the transferrin allelic diversity of five hatchery stocks of tambaqui (Colossoma macropomum. The tambaqui stock from Pentecoste, the oldest maintained in Brazilian hatchery stations, retained three of the six alleles detected in wild populations of tambaqui from the Amazon River. Other hatchery stocks, directly or indirectly derived from the Pentecoste stock, did not show transferrin allelic variability. Insufficient number of founders and genetic drift due to sampling errors seem to be the main causes leading to loss of genetic diversity in tambaqui hatchery stocks. Appropriate management strategies are required in order to improve the genetic potential of tambaqui stocks in Brazil.

Calcagnotto Daniela

2000-01-01

158

Identification and phylogenetic inferences on stocks of sharks affected by the fishing industry off the Northern coast of Brazil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ongoing decline in abundance and diversity of shark stocks, primarily due to uncontrolled fishery exploitation, is a worldwide problem. An additional problem for the development of conservation and management programmes is the identification of species diversity within a given area, given the morphological similarities among shark species, and the typical disembarkation of processed carcasses which are almost impossible to differentiate. The main aim of the present study was to identify t...

Luis Fernando da Silva Rodrigues-Filho; Tainá Carreira da Rocha; Péricles Sena do Rêgo; Horacio Schneider; Iracilda Sampaio; Marcelo Vallinoto

2009-01-01

159

A cross-ecosystem comparison of spatial and temporal patterns of covariation in the recruitment of functionally analogous fish stocks  

Science.gov (United States)

Temporal and spatial patterns of recruitment ( R) and spawning stock biomass ( S) variability were compared among functionally analogous species and similar feeding guilds from six marine ecosystems. Data were aggregated into four regions including the Gulf of Maine/Georges Bank, the Norwegian/Barents Seas, the eastern Bering Sea, and the Gulf of Alaska. Variability was characterized by calculating coefficients of variation and anomalies for three response variables: ln( R), ln( R/ S), and stock-recruit model residuals. Patterns of synchrony and asynchrony in the response variables were examined among and between ecosystems, between- and within-ocean basins and among functionally analogous species groups using pair-wise correlation analysis corrected for within-time series autocorrelation, multivariate cross-correlation analyses and regime shift detectors. Time series trends in response variables showed consistent within basin similarities and consistent and coherent differences between the Atlantic and Pacific basin ecosystems. Regime shift detection algorithms identified two broad-scale regime shift time periods for the pelagic feeding guild (1972-1976 and 1999-2002) and possibly one for the benthic feeding guild (1999-2002). No spatial patterns in response variable coefficients of variation were observed. Results from multivariate cross-correlation analysis showed similar trends. The data suggest common external factors act in synchrony on stocks within ocean basins but temporal stock patterns, often of the same species or functional group, between basins change in opposition to each other. Basin-scale results (similar within but different between) suggest that the two geographically broad areas are connected by unknown mechanisms that, depending on the year, may influence the two basins in opposite ways. This work demonstrates that commonalities and synchronies in recruitment fluctuations can be found across geographically distant ecosystems but biophysical causes of the fluctuations remain difficult to identify.

Megrey, Bernard A.; Hare, Jonathan A.; Stockhausen, William T.; Dommasnes, Are; Gjøsæter, Harald; Overholtz, William; Gaichas, Sarah; Skaret, Georg; Falk-Petersen, Jannike; Link, Jason S.; Friedland, Kevin D.

2009-04-01

160

Assessment of the Marketing of Frozen Fish (Iced Fish in Edo State, Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available The study examines the marketing of frozen fish in Edo State of Nigeria. The primary data used for the study were derived using structured questionnaires administered to 180 randomly selected frozen fish marketers from six markets. Both descriptive and inferential statistics were used in data analysis. From the findings, marketing of fish is mainly carried out by females, most of the respondents are in the economically active age group and are mostly married; they have a lot of experience in the business, majority of them are retailers selling less than four cartons of fish on daily basis and most of them have formal education. From the gross margin analysis and t-test, marketing of frozen fish is profitable in the area. However, it was recommended that major constraints like poor storage/preservation, inadequate capital and marketing costs should be tackled to improve the efficiency of marketing system of frozen fish in the State.

Ebewore Solomon Okeoghene

2013-09-01

 
 
 
 
161

Exposure assessment for trace elements from consumption of marine fish in Southeast Asia  

International Nuclear Information System (INIS)

Concentrations of 20 trace elements were determined in muscle and liver of 34 species of marine fish collected from coastal areas of Cambodia, Indonesia, Malaysia and Thailand. Large regional difference was observed in the levels of trace elements in liver of one fish family (Carangidae): the highest mean concentration was observed in fish from the Malaysian coastal waters for V, Cr, Zn, Pb and Bi and those from the Java Sea side of Indonesia for Sn and Hg. To assess the health risk to the Southeast Asian populations from consumption of fish, intake rates of trace elements were estimated. Some marine fish showed Hg levels higher than the guideline values by U.S. Environmental Protection Agency and Joint FAO/WHO Expert Committee on Food Additives (JECFA). This suggests that consumption of these fish may be hazardous to the people. -- Intake of mercury through consumption of some marine fish species might be hazardous to the people in Southeast Asia

162

Exposure assessment for trace elements from consumption of marine fish in Southeast Asia  

Energy Technology Data Exchange (ETDEWEB)

Concentrations of 20 trace elements were determined in muscle and liver of 34 species of marine fish collected from coastal areas of Cambodia, Indonesia, Malaysia and Thailand. Large regional difference was observed in the levels of trace elements in liver of one fish family (Carangidae): the highest mean concentration was observed in fish from the Malaysian coastal waters for V, Cr, Zn, Pb and Bi and those from the Java Sea side of Indonesia for Sn and Hg. To assess the health risk to the Southeast Asian populations from consumption of fish, intake rates of trace elements were estimated. Some marine fish showed Hg levels higher than the guideline values by U.S. Environmental Protection Agency and Joint FAO/WHO Expert Committee on Food Additives (JECFA). This suggests that consumption of these fish may be hazardous to the people. -- Intake of mercury through consumption of some marine fish species might be hazardous to the people in Southeast Asia.

Agusa, Tetsuro [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); Kunito, Takashi [Department of Environmental Sciences, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621 (Japan); Sudaryanto, Agus [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); Monirith, In [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); Kan-Atireklap, Supawat [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); Iwata, Hisato [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); Ismail, Ahmad [Department of Biology, Faculty of Science and Environmental Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sanguansin, Joompol [Eastern Marine Fisheries Development Center, Ban Phe, Muang, Rayong 21160 (Thailand); Muchtar, Muswerry [Research and Development Center for Oceanology Indonesia Institute of Sciences, Jl. Pasir Putih 1, Ancol Timur, Jakarta 11048 (Indonesia); Tana, Touch Seang [Social and Cultural Observation Unit (OBSES), Office of the Council of Ministers, Phnom Penh (Cambodia); Tanabe, Shinsuke [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan)]. E-mail: shinsuke@agr.ehime-u.ac.jp

2007-02-15

163

An assessment of fish mortality at the Rance tidal power barrage, Brittany, France  

International Nuclear Information System (INIS)

This report describes the results of three weeks field work carried out on the Rance Estuary in August 1991. The objectives were to make a preliminary assessment of the relative frequency with which dead fish accumulate in the Rance barrage lock pit; to assess the likely cause of mortality; and to assess the success with which marine fish migrate across a tidal barrage by tagging a variety of species within the barrage basin. (author)

164

Performance Assessment of the Food Industry of Tehran Stock Exchange Based on Balanced Score Card (BSC) Technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Major objective of the present paper was to study the role of balanced score card regarding performance assessment of companies listed in food and beverage industry in the stock exchange. This survey is descriptive and is regarded as a quasi-experimental research plan (Ex-Post design). The statistical population included 200 managers and research sample consisted of 99 persons based on Cochran formula. Questionnaire was used for data collection. Frequency tables and appropriate diagrams were ...

Morteza Asadi; Javad Mehrabi; Saharnaz Mohseni; Mohammad Hasan Tanhaei

2013-01-01

165

Proposal of a method for assessing the quality of stock photography websites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The advent of the Internet, the advent of digital photography and the chance of digitalizing large volumes of photographs, negatives, slides or daguerreotypes revolutionized the field of commercial stock photography. This new digital environment forced stock photography to adapt to the changing needs of its users. One of the main measures that these agencies were faced with these new needs of users was to create their own websites through which to offer their products to their customers. Pap...

Garcia, Sandra Maria Gonzalez

2012-01-01

166

Histological methods in the assessment of different feed effects on liver and intestine of fish  

Directory of Open Access Journals (Sweden)

Full Text Available This manuscript describes the importance of using histological methods to assess the effects of feed on the liver and intestine of fish. Due to the constantly increasing world production of fish and other aquatic organisms, it is necessary to replace fishmeal and fish oil in diets with less expensive raw materials of plant origin. Due to the increased fiber content, increased presence of carbohydrates, antinutritional factors, and inappropriate content of amino acids and new compounds can have negative effects on the digestive system of fish and therefore on fitness, health and production characteristics of cultivated fish. The liver and intestines are the most important organs for the digestion and absorption of nutrients from feed. Therefore, monitoring histological structure of fish liver and intestine is the method of choice in assessing the effects of nutrient mixtures that use raw materials of plant origin. For both of these vital organs the normal histological structure and the most important results obtained by research are discussed. This paper presents a critical review of the histological methods used in research on feed effects. Results related to the negative effects of raw soy-based feed on the occurrence of enteritis in carnivorous fish species are discussed. The results point out that use of modern approach in fish pathology such as improved histochemical, stereological, scoring, and other analytical methods could be a beneficial approach in an accurate assessment of new feed effects on fish.

Raškovi? Božidar S.

2011-01-01

167

Wavelet decomposition and regime shifts. Assessing the effects of crude oil shocks on stock market returns  

Energy Technology Data Exchange (ETDEWEB)

While there is a large body of empirical studies on the relationship between crude oil price changes and stock market returns, they have failed to achieve a consensus on this subject. In this paper, we combine wavelet analysis and Markov Switching Vector Autoregressive (MS-VAR) approach to explore the impact of the crude oil (CO) shocks on the stock market returns for UK, France and Japan over the period from January 1989 to December 2007. Our procedure involves the estimation of the extended MS-VAR model in order to investigate the importance of the resultant wavelet filtering series (after removing random components) in determining the behavior of the stock market volatilities. We show that CO shocks do not affect the recession stock market phases (except for Japan). However, they significantly reduce moderate and/or expansion stock market phases temporarily. Moreover, this negative relationship appears to be more pronounced during the pre-1999 period. The empirical findings will prove extremely useful to investors who need to understand the exact effect of international oil changes on certain stocks prices as well as for policy managers who need a more thorough evaluation about the efficiency of hedging policies affected by oil price changes. (author)

Jammazi, Rania; Aloui, Chaker [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

2010-03-15

168

Wavelet decomposition and regime shifts: Assessing the effects of crude oil shocks on stock market returns  

Energy Technology Data Exchange (ETDEWEB)

While there is a large body of empirical studies on the relationship between crude oil price changes and stock market returns, they have failed to achieve a consensus on this subject. In this paper, we combine wavelet analysis and Markov Switching Vector Autoregressive (MS-VAR) approach to explore the impact of the crude oil (CO) shocks on the stock market returns for UK, France and Japan over the period from January 1989 to December 2007. Our procedure involves the estimation of the extended MS-VAR model in order to investigate the importance of the resultant wavelet filtering series (after removing random components) in determining the behavior of the stock market volatilities. We show that CO shocks do not affect the recession stock market phases (except for Japan). However, they significantly reduce moderate and/or expansion stock market phases temporarily. Moreover, this negative relationship appears to be more pronounced during the pre-1999 period. The empirical findings will prove extremely useful to investors who need to understand the exact effect of international oil changes on certain stocks prices as well as for policy managers who need a more thorough evaluation about the efficiency of hedging policies affected by oil price changes.

Jammazi, Rania, E-mail: jamrania2@yahoo.f [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia); Aloui, Chaker, E-mail: chaker.aloui@fsegt.rnu.t [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

2010-03-15

169

Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA, on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

Jan A. Venter

2012-09-01

170

Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A preliminary assessment of surf-zone and estuarine line fish was carried out in the Dwesa-Cwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a cons [...] ervation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA. CONSERVATION IMPLICATIONS: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

J.A., Venter; B.Q., Mann.

171

Environmental assessment, K Pool fish rearing, Hanford Site, Richland, Washington  

International Nuclear Information System (INIS)

The US Department of Energy (DOE) has a need to respond to a request to lease facilities at the Hanford Site 100-KE and 100-KW filter plant pools (K Pools) for fish rearing activities. These fish rearing activities would be: (1) business ventures with public and private funds and (2) long-term enhancement and supplementation programs for game fish populations in the Columbia River Basin. The proposed action is to enter into a use permit or lease agreement with the YIN or other parties who would rear fish in the 100-K Area Pools. The proposed action would include necessary piping, pump, and electrical upgrades of the facility; cleaning and preparation of the pools; water withdrawal from the Columbia River, and any necessary water or wastewater treatment; and introduction, rearing and release of fish. Future commercial operations may be included

172

Conception of the artisanal fisherfolk who use Furnas Reservoir, Minas Gerais State, about fishing stocks: an ethnoichthyological study  

Directory of Open Access Journals (Sweden)

Full Text Available Ethnoichthyology, based on ecological parameters, can be a very useful tool to study man-made environmental changes. These changes are perceived by individuals who fish for a living and/or recreational activities in the impacted environs. The objective of this study was to investigate how the artisanal fisherfolk of the municipality of Carmo do Rio Claro, Minas Gerais, perceive the environmental changes caused by anthropogenic actions. The data were collected from August 2009 to January 2010 by means of openended interviews according to usual ethnographical techniques. Fifty professional fisherfolk were interviewed, forty-nine men and one woman. The results showed that they had experienced a reduction of fishing resources, the disappearance and/or rarity of some species, and the introduction of species. This pointed to the necessity of seeking the best ways to recover and conserve the native species of the Furnas Reservoir, in addition to a better monitoring of the introduced species.

Valter Monteiro de Azevedo-Santos

2010-12-01

173

Contribution of estuarine nursery areas to the structure and biocontamination of stocks of commercially fish species along the portuguese coast  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Identifying the relative importance of estuaries as effective nurseries for marine fish juveniles isessential to understand the processes defining the life cycle and structure of these species'meta-populations and raises scientific interest due to the ecological and economical importanceof directly associated functions and resources. In the present work, some of the mainPortuguese estuaries (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosaand Guadiana) and commercially impo...

Vasconcelos, Rita Maria Pina

2009-01-01

174

Life Cycle Assessment on Icelandic seafood product based on two different fishing methods. Environmental impacts from fisheries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Human population is ever increasing. Population in 2009 is currently approaching 7 billion people and is expected to become 9.7 billion in 2050. Seafood is an important protein income for humans. According to FAO, more than 80% of all fish stock on Earth are either fully exploited or over exploited. Fisheries have considerable environmental impacts such as effects on seafloor caused by fishing gear, effects on biodiversity, use of fossil fuels and other chemicals that contribute to climate ch...

Aðalbjörg Birna Guttormsdóttir 1978

2009-01-01

175

Commercial fish species of inland waters: A model for sustainability assessment and management.  

Science.gov (United States)

The permanent increase in the exploitation of commercial fish species has led to the need for developing practical and effective tools for the sustainability assessment and management of the target fish populations. The aim of this study was to formulate an ESHIPPOfishing model which would provide a reliable assessment of commercial fish population sustainability and indicate the conservation priorities. The existing ESHIPPO model was modified by introducing a new Index of local sustainability of fish populations (ILSFP) which enables the selection of "keystone populations" and "keystone habitats/ecosystems" within the basin being investigated. We employed a self-organizing map (SOM) in order to visualize the spatial distribution of the keystone populations and keystone habitats/ecosystems for each fish species. Based on the ILSFP values, environmental specialization (ES) of a fish species and local environmental factors (HIPPO factors), the model estimates the degree of sustainability (DS) of commercial fish populations in the freshwater ecosystems of the western Balkan Peninsula. The results indicate a low degree of sustainability for the majority of commercial fish species of the Middle Danube Basin, especially Acipenser ruthenus and Hucho hucho. The ESHIPPOfishing model presents a cost effective conservation approach, formulated to be applicable to any kind of river basin. The application of the ESHIPPOfishing model provides a comprehensive insight into the viability of target fish populations, which would not only further improve the selection of conservation priorities, but also facilitate the management of aquatic ecosystems. PMID:25170830

Simi?, Vladica M; Simi?, Snežana B; Stojkovi? Piperac, Milica; Petrovi?, Ana; Miloševi?, Djuradj

2014-11-01

176

Genotoxicity Assessment of Mercuric Chloride in the Marine Fish Therapon jaruba.  

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Full Text Available The aim of the present study was to standardize and to assess the predictive value of the cytogenetic analysis by Micronucleus (MN test in fish erythrocytes as a biomarker for marine environmental contamination. Micronucleus frequency baseline in erythrocytes was evaluated in and genotoxic potential of a common chemical was determined in fish experimentally exposed in aquarium under controlled conditions. Fish (Therapon jaruba were exposed for 96 h to a single heavy metal (mercuric chloride. Chromosomal damage was determined as micronuclei frequency in fish erythrocytes. Significant increase in MN frequency was observed in erythrocytes of fish exposed to mercuric chloride. Concentration of 0.25 ppm induced the highest MN frequency (2.95 micronucleated cells/1000 cells compared to 1 MNcell/1000 cells in control animals. The study revealed that micronucleus test, as an index of cumulative exposure, appears to be a sensitive model to evaluate genotoxic compounds in fish under controlled conditions.

Nagarajan Nagarani

2009-07-01

177

Empirical assessment of the Hellenic non-residential building stock, energy consumption, emissions and potential energy savings  

International Nuclear Information System (INIS)

Comprehensive information and detailed data for the non-residential (NR) building stock is rather limited, although it is the fastest growing energy demand sector. This paper elaborates the approach used to determine the potential energy conservation in the Hellenic NR building stock. A major obstacle that had to be overcome was the need to make suitable assumptions for missing detailed primary data. A qualitative and quantitative assessment of scattered national data resulted in a realistic assessment of the existing NR building stock and energy consumption. Different energy conservation scenarios and their impact on the reduction of CO2 emissions were evaluated. Accordingly, the most effective energy conservation measures are: addition of thermal insulation of exposed external walls, primarily in hotels and hospitals; installation of energy efficient lamps; installation of solar collectors for sanitary hot water production, primarily in hotels and health care; installation of building management systems in office/commercial and hotel buildings; replacement of old inefficient boilers; and regular maintenance of central heating boilers

178

New Archaeozoological Data from the Fayum "Neolithic" with a Critical Assessment of the Evidence for Early Stock Keeping in Egypt  

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Faunal evidence from the Fayum Neolithic is often cited in the framework of early stock keeping in Egypt. However, the data suffer from a number of problems. In the present paper, large faunal datasets from new excavations at Kom K and Kom W (4850–4250 BC) are presented. They clearly show that, despite the presence of domesticates, fish predominate in the animal bone assemblages. In this sense, there is continuity with the earlier Holocene occupation from the Fayum, starting ca. 7350 BC. Domesticated plants and animals appear first from approximately 5400 BC. The earliest possible evidence for domesticates in Egypt are the very controversial domesticated cattle from the 9th/8th millennium BC in the Nabta Playa-Bir Kiseiba area. The earliest domesticates found elsewhere in Egypt date to the 6th millennium BC. The numbers of bones are generally extremely low at this point in time and only caprines are present. From the 5th millennium BC, the numbers of sites with domesticates dramatically increase, more species are also involved and they are usually represented by significant quantities of bones. The data from the Fayum reflect this two phase development, with very limited evidence for domesticates in the 6th millennium BC and more abundant and clearer indications in the 5th millennium BC. Any modelling of early food production in Egypt suffers from poor amounts of data, bias due to differential preservation and visibility of sites and archaeological remains, and a lack of direct dates for domesticates. In general, however, the evidence for early stock keeping and accompanying archaeological features shows large regional variation and seems to be mainly dependent on local environmental conditions. The large numbers of fish at Kom K and Kom W reflect the proximity of Lake Qarun. PMID:25310283

Linseele, Veerle; Van Neer, Wim; Thys, Sofie; Phillipps, Rebecca; Cappers, Rene; Wendrich, Willeke; Holdaway, Simon

2014-01-01

179

New archaeozoological data from the fayum "neolithic" with a critical assessment of the evidence for early stock keeping in egypt.  

Science.gov (United States)

Faunal evidence from the Fayum Neolithic is often cited in the framework of early stock keeping in Egypt. However, the data suffer from a number of problems. In the present paper, large faunal datasets from new excavations at Kom K and Kom W (4850-4250 BC) are presented. They clearly show that, despite the presence of domesticates, fish predominate in the animal bone assemblages. In this sense, there is continuity with the earlier Holocene occupation from the Fayum, starting ca. 7350 BC. Domesticated plants and animals appear first from approximately 5400 BC. The earliest possible evidence for domesticates in Egypt are the very controversial domesticated cattle from the 9th/8th millennium BC in the Nabta Playa-Bir Kiseiba area. The earliest domesticates found elsewhere in Egypt date to the 6th millennium BC. The numbers of bones are generally extremely low at this point in time and only caprines are present. From the 5th millennium BC, the numbers of sites with domesticates dramatically increase, more species are also involved and they are usually represented by significant quantities of bones. The data from the Fayum reflect this two phase development, with very limited evidence for domesticates in the 6th millennium BC and more abundant and clearer indications in the 5th millennium BC. Any modelling of early food production in Egypt suffers from poor amounts of data, bias due to differential preservation and visibility of sites and archaeological remains, and a lack of direct dates for domesticates. In general, however, the evidence for early stock keeping and accompanying archaeological features shows large regional variation and seems to be mainly dependent on local environmental conditions. The large numbers of fish at Kom K and Kom W reflect the proximity of Lake Qarun. PMID:25310283

Linseele, Veerle; Van Neer, Wim; Thys, Sofie; Phillipps, Rebecca; Cappers, René; Wendrich, Willeke; Holdaway, Simon

2014-01-01

180

Impact Assessment for the Reduction in Fishing Capacity for the ...  

achieved through market forces alone, as the incentive will exist for fishermen to \\fish ...... segmentation would be vessels' record of landing quota species using \\..... (FTE) employees are considered small and medium sized enterprises (SME).

 
 
 
 
181

Temporal changes in European eel, Anguilla anguilla, stocks in a small catchment after installation of fish passes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Changes in the abundance of European eel, Anguilla anguilla L., in the River Fre'mur, France, were examined over an 8-year period. Natural connectivity of the river was disturbed by three high dams that inhibited eel upstream migration and reduced recruitment by elvers and yellow eels. After eel passes were installed, fish became more abundant upstream (mean density 0.5 eel m)2). Moreover, except in the more upstream areas, no decline in eel numbers and biomass was found, in contrast to the g...

Laffaille, Pascal; Acou, Anthony; Guilloue?t, Je?ro?me; Legault, Antoine

2005-01-01

182

Qualitative assessment of imported frozen fish fillets in Sulaimani markets  

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Full Text Available This study aims to determine the quality of frozen fish fillets sold in Sulaimani city markets a total number of (64 sample of frozen fish fillets belonged to 4 foreign trademarks were collected from different parts of Sulaimani markets. The samples were subjected to physical and chemical tests to determine their quality and suitability for human consumption. The proximate chemical analysis referred to presence of significant differences in moisture, fat and protein content among the four trademarks except for ash content. While the physical indices showed that White fish fillets recorded the lowest thawing and cooking loss which in return recorded the highest WHC. Chemical indices showed that the pH mean values of Myanmar and Flander mark were significantly differed (P<0.05 than Hasson and White fish fillet, Although, the results of FFA recorded no significant differences among the trademarks, and Flander mark recorded the highest PV and TBA among the other which made it significantly differed than them and White fish fillet recorded the lowest, still, they were within the international standard limits. Where, the results of TVN values recorded no significant differences ( among the inspected marks. All obtained results referred to the validity of these fish fillets for human consumption.

Z.K. Khidhir

2013-06-01

183

Challenges in using fish communities for assessing the ecological integrity of non-perennial rivers  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english Environmental Water Assessments (EWAs) aim to protect the ecological integrity of rivers amidst increasing anthropogenic pressures on freshwater resources, and fish communities are the ecosystem component most commonly included. The Fish Response Assessment Index (FRAI) was developed to assess the i [...] ntegrity of fish communities in South African rivers and is commonly applied in EWA studies. This paper reports on the suitability of the FRAI for the non-perennial Seekoei River and discusses some of the challenges faced. Our relatively long and thorough study on the Seekoei River confirmed the concerns that earlier, snapshot, fish integrity assessments in the Orange River system raised: that the existing fish indices are not ideally suited for these rivers with their naturally low species richness and hardy, generalist fish communities. Other difficulties with the use of a score-based method include prediction of the expected species, calculation of a frequency of occurrence rating, selection of the right sampling times for comparative purposes, loss of habitats and sampling points under different flow conditions, and problems experienced when using accumulated data to try to correct for a situation of having too few sampling points. At this stage a more generalised approach is suggested for the Seekoei River, and ultimately other similar non-perennial systems. This could include a number of community characteristics, such as abundance, species richness, species diversity and evenness, recruitment, fish health and the presence/absence of exotic species.

MF, Avenant.

2010-07-01

184

Question of the Day: Regeneration of Fish  

Science.gov (United States)

The two figures shown above are from the The Fishing Game (more info) game. They show the number of new fish per year that are added to the fish "stock," depending on the maximum number of fish that the ...

185

Comparison of methods for measuring and assessing carbon stocks and carbon stock changes in terrestrial carbon pools. How do the accuracy and precision of current methods compare? A systematic review protocol  

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Full Text Available Abstract Background Climate change and high rates of global carbon emissions have focussed attention on the need for high-quality monitoring systems to assess how much carbon is present in terrestrial systems and how these change over time. The choice of system to adopt should be guided by good science. There is a growing body of scientific and technical information on ground-based and remote sensing methods of carbon measurement. The adequacy and comparability of these different systems have not been fully evaluated. Methods A systematic review will compare methods of assessing carbon stocks and carbon stock changes in key land use categories, including, forest land, cropland, grassland, and wetlands, in terrestrial carbon pools that can be accounted for under the Kyoto protocol (above- ground biomass, below-ground biomass, dead wood, litter and soil carbon. Assessing carbon in harvested wood products will not be considered in this review. Discussion Developing effective mitigation strategies to reduce carbon emissions and equitable adaptation strategies to cope with increasing global temperatures will rely on robust scientific information that is free from biases imposed by national and commercial interests. A systematic review of the methods used for assessing carbon stocks and carbon stock changes will contribute to the transparent analysis of complex and often contradictory science.

Petrokofsky Gillian

2012-06-01

186

A Stock Assessment of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) for Sustainable Management in Kung Krabaen Bay, Gulf of Thailand.  

Science.gov (United States)

A stock assessment of blue swimming crabs, Portunus pelagicus was conducted with crab gill nets and collapsible crab traps at Kung Krabaen Bay, in the eastern Gulf of Thailand, from 2008 to 2009. Several key indicators show that P. pelagicus population is in crisis. Fishing mortality shows an increase to 4.14. The exploitation rate is 0.71, higher than the optimal value of 0.38. The size of the mature females has also decreased from 8.10±0.39 cm to 7.52±1.14 cm. The average fecundity is 0.572×10(6)±0.261×10(6) eggs per batch, and the sex ratio (male:female) is 1:0.92. Based on these results, a sustainable management program for P. pelagicus was proposed as follows: (i) closing the bay during the spawning season, (ii) restoration of the Enhalus acoroides seagrass beds, (iii) restocking crab larvae in the bay and (iv) educating and networking all stakeholders to develop a better understanding of the ecology of the crab to support sustainable fishery management in Kung Krabaen Bay. PMID:25210587

Kunsook, Chutapa; Gajaseni, Nantana; Paphavasit, Nittharatana

2014-08-01

187

Fish as bioindicators in aquatic environmental pollution assessment: A case study in Lake Victoria wetlands, Uganda  

Science.gov (United States)

Growing human population and industrialization have led to the pollution of most aquatic ecosystems and consequent deterioration in environmental water quality. Indicator organisms are needed to improve assessment programmes on the ecological impacts of anthropogenic activities on the aquatic environment. Fish have been widely documented as useful indicators of environmental water quality because of their differential sensitivity to pollution. This study investigated the environmental water quality of selected wetland ecosystems using fish as biological indicators. Fish community structure in relation to water quality was assessed in five wetlands along the shoreline of Lake Victoria from August 2006 to June 2008. Four urban wetlands were variedly impacted by anthropogenic activities while one rural wetland was less impacted, and served as a reference site. Fish species diversity, abundance and richness were assessed, and canonical correspondence analysis (CCA) was used to evaluate the relationship between the fish communities and environmental variables. Results revealed that urban effluent impacted negatively on water quality and consequently the fish community structure. A total of 29 fish species were recorded throughout the study with the lowest number of 15 species recorded in the most impacted site. Shannon diversity and Margalef species richness indices were highest at the references site and lowest at the most impacted site. Wetland haplochromis species dominated the reference site, while oreochromis species dominated the most impacted site. The inshore locations registered higher species diversity and low species richness than the offshore locations. Low dissolved oxygen, pH, secchi depth and high electrical conductivity, total phosphorous, and total nitrogen were strongly associated with the effluent-impacted sites and greatly influenced the fish community structure. This study recommends the use of fish as valuable biological indicators in aquatic environmental pollution assessment.

Naigaga, I.; Kaiser, H.; Muller, W. J.; Ojok, L.; Mbabazi, D.; Magezi, G.; Muhumuza, E.

188

Assessment of fishing the valuable hydrobionts in the Sivash bay  

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Full Text Available The perennial analysis of the production of the main industrial objects by private entrepreneurs in the Sivash bay is presented. The prohibition of the plaice-Glossa’s catch is saved. There is the reduction in net catches of haarder due to the decrease of the livestock herd, the poaching fishing, the water pollution of spawning places and graziery, and the lack of control by the fish inspection. The introduction of the serious control of mullet’s catch and good graziery conditions for this spe-cies facilitates to the restoration of their natural population. The pigfish are the additional objects of the catch with a slight annual increase in their number in catches, but they don’t have the significant influence on the formation of the overall productivity of fish in the Sivash bay. The larvae of hironomus takes the first place of the production on the territory of the East Sivash. There is a gradual advance of the whole productivity of fish in the east part of the Sivash bay, at the expense catching mullet, haarder and hironomus larvae.

Kireeva Irina Yurievna

2013-09-01

189

Predictive models for fish assemblages in eastern USA streams: implications for assessing biodiversity  

Science.gov (United States)

Management and conservation of aquatic systems require the ability to assess biological conditions and identify changes in biodiversity. Predictive models for fish assemblages were constructed to assess biological condition and changes in biodiversity for streams sampled in the eastern United States as part of the U.S. Geological Survey's National Water Quality Assessment Program. Separate predictive models were developed for northern and southern regions. Reference sites were designated using land cover and local professional judgment. Taxonomic completeness was quantified based on the ratio of the number of observed native fish species expected to occur to the number of expected native fish species. Models for both regions accurately predicted fish species composition at reference sites with relatively high precision and low bias. In general, species that occurred less frequently than expected (decreasers) tended to prefer riffle areas and larger substrates, such as gravel and cobble, whereas increaser species (occurring more frequently than expected) tended to prefer pools, backwater areas, and vegetated and sand substrates. In the north, the percentage of species identified as increasers and the percentage identified as decreasers were equal, whereas in the south nearly two-thirds of the species examined were identified as decreasers. Predictive models of fish species can provide a standardized indicator for consistent assessments of biological condition at varying spatial scales and critical information for an improved understanding of fish species that are potentially at risk of loss with changing water quality conditions.

Meador, Michael R.; Carlisle, Daren M.

2009-01-01

190

Evaluation of generalized habitat criteria for assessing impacts of altered flow regimes on warmwater fishes  

Science.gov (United States)

Assessing potential effects of flow regulation on southeastern warmwater fish assemblages is problematic because of high species richness and our poor knowledge of habitat requirements for most species. A previous attempt to reduce the complexity of describing habitat requirements for diverse assemblages defined five 'key habitat' types based on quantitative descriptions of depth, velocity, substrate, and cover for assessing the effects of streamflow alteration on fish communities. Our study investigated relationships between availability and temporal stability of key habitats and fish abundances at regulated and unregulated sites in the Tallapoosa River system. Fish assemblage characteristics at seven sites were quantified based on 1,400 electrofishing samples collected during 1994 and 1995. Simulations were used to model availability and temporal stability of key habitats at regulated and unregulated sites, Associations between fish assemblages and availability or stability of key habitats were identified using correlation analysis. We found that hydropeaking dam operation reduced the average length of time that shallow-water habitats were stable during the spring and summer and also reduced year-to-year variation in the stability of shallow-water habitats compared to unregulated sites. Within-site comparisons of fish and habitat variables indicated that differences in fish abundances correlated with differences in the availability and temporal stability of shallow-water habitats. Additionally, groups of stream fishes defined by taxonomy or differences in orientation to the substrate and feeding mode responded similarly to changes in key habitat availability. These findings demonstrate that the temporal and spatial availability of key habitats could serve as a useful measure of the potential effects of flow alteration on lotic fish assemblages, and suggest that both short-term temporal stability of key habitats as well as annual variation in key habitat availability are important for maintaining diverse fish assemblages.

Bowen, Z.H.; Freeman, M.C.; Bovee, K.D.

1998-01-01

191

Veterinary surveillance - Fish  

May 4, 2010 ... Fish farming is defined as the keeping of live fish with a view to their sale or \\transfer ... fish stocks and their habitat, and with minimising the impact of ... of fish \\present are indicators of the health of the freshwater environment.

192

Species and global change-assessing the extinction point of albacore stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Global change determines the environmental condition and leads to decide the carrying capacity. While carrying capacity determines the extinction of the species, it is an important issue to estimate the extinction point of the species, the minimal carrying capacity, or the tolerant limitation of the species. If it is possible to estimate the tolerant limitation of the species, it will be possible to control the global change. Applied the above idea to the albacore stocks, it revealed that ext...

Shyh-Bin Wang; Chien-Hsiung Wang

2012-01-01

193

Overview of the French organic spreaders stock: State of the art and performance assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The French stock of organic spreader evolves and presents differences by their users. Cuma and agricultural work companies are the main operators which buy machines and provide spreading services for farmers. Individual sales are currently at a low level. The market decreases in units sold but prices increase. In this context, operators renew spreaders after 7-8 years and over 10 years for tankers, replacing small machines with bigger ones. Cuma use mostly vertical rotors spreaders for solid ...

Mazoyer, J.; Pradel, M.

2013-01-01

194

Assessment of the relationship between oil prices and US oil stocks  

International Nuclear Information System (INIS)

This paper qualitatively and quantitatively analyzes the relationship between US monthly ending oil stocks position with that of West Texas Intermediate (WTI) oil prices from February 1995 to July 2004. The paper concludes if other things are held constant, WTI is inversely related to the petroleum products (PPP), combined petroleum products and crude oil (CPPP), crude oil alone (Crude), total oil stocks including petroleum products, crude oil and strategic petroleum reserves SPR (Total), total gasoline (TGO), total distillate (TDO). It could not establish a statistically significant and negative relationship with SPR when run alone. One percent increase (decrease) in CPPP, PPP, Crude, Total, TGO and TDO leads to decrease (increase) in WTI, respectively, by 0.70, 0.43, 0.37, 0.97, 0.26 and 0.21 percent. Oil prices are largely influenced by total crude and Crude and PPP inventories levels while modestly with variations in gasoline and distillate stocks levels. Despite a healthy increase of over 22 percent in SPR from January 2001 to April 2004, it did not result in easing of oil prices. Primarily because SPR are meant for security of supply concern and are only released under extreme conditions by the President of United States, they are neither meant for the purposes of balancing supply-demand gap nor for the stability of oil prices. The aggressive SPR buildup in recent years is related to international terrorism, geopolitical situation in the Middle East, particularly in Iraq, that encourages US government to enhance its SPR to meet any short-term eventuality. The analyst must keep a close eye on CPPP and the total oil stocks variation to forecast WTI in the short run whilst gasoline and distillate influence oil prices modestly in the short run. SPR, on the other hand, are expected to play a pivotal role in balancing oil prices and in providing a critical resource for the economy in case of any major shortfall in the long run

195

Chemical and biochemical tools to assess pollution exposure in cultured fish  

Energy Technology Data Exchange (ETDEWEB)

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.

Fernandes, Denise [C.I.M.A., University of Algarve, F.C.M.A., Campus de Gambelas, 8005-139 Faro (Portugal); Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, 08034 Barcelona (Spain); Zanuy, Silvia [Department of Fish Reproductive Physiology, IATS-CSIC, 12595 Castellon (Spain); Bebianno, Maria Joao [C.I.M.A., University of Algarve, F.C.M.A., Campus de Gambelas, 8005-139 Faro (Portugal); Porte, Cinta [Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, 08034 Barcelona (Spain)], E-mail: cpvqam@cid.csic.es

2008-03-15

196

Chemical and biochemical tools to assess pollution exposure in cultured fish  

International Nuclear Information System (INIS)

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

197

Contaminant exposure in Montrealers of Asian origin fishing the St. Lawrence River: Exploratory assessment  

Energy Technology Data Exchange (ETDEWEB)

Fishing and fish consumption are widely practiced among members of certain ethnocultural groups. Information assessment led them to ascribe high levels of consumption of locally caught sportfish to Montrealers of Asian origin and to hypothesize that their choices of species and fish organs differ from those of the majority group. An exploratory assessment of contaminant bioindicators reflective of St. Lawrence river fish consumption was conducted in late 1995 among nine Vietnamese and nine Bangladeshi Montreal sportfishers identified by community contacts. Vietnamese participants, six men and three women, were 27--70 years of age and had immigrated to Canada 3--20 years earlier. In contrast, the nine Bangladeshi males aged 28--41 years had been in Canada for 2--13 years. Bioindicator concentrations among Bangladeshi and Vietnamese participants are compared to those found for majority-community Montreal-area high-level consumers recruited on the St. Lawrence River during winter 1995.

Kosatsky, T. [Montreal Public Health Program, Quebec (Canada)]|[McGill Univ., Montreal, Quebec (Canada). Dept. of Occupational Health]|[Quebec Toxicology Center, Montreal, Quebec (Canada); Przybysz, R.; Shatenstein, B. [Montreal Public Health Program, Quebec (Canada)]|[McGill Univ., Montreal, Quebec (Canada). Dept. of Occupational Health; Weber, J.P. [Quebec Toxicology Center, Montreal, Quebec (Canada); Armstrong, B. [London School of Hygiene (United Kingdom)

1999-02-01

198

Fish abundance differences and relations to primary production in two variants of pond stocking with common carp(Cyprinus carpio L., grass carp (Ctenopharyngodon idella Val. and bighead carp (Aristichthys nobilis Rich. larvae  

Directory of Open Access Journals (Sweden)

Full Text Available A fish pond experiment was conducted in two ponds which were stocked with 0 aged common carp and bighead carp larvae in numeric abundance ratio 3:1 (variant 1 while in other two ponds the ratio was 1:3 in favor of bighead carp (variant 2. To each of the two stocking variants we added one and the same number of 0 aged grass carps and 1+ or 2+ common carps. The experiment lasted 4 months (May to September and was repeated in two consecutive years (2007, 2008. The second year variant 2 was conducted in three ponds. The fish ponds belonged to the experimental facilities of the Institute for Fishery and Aquaculture, Bulgaria. The plankton primary production and other related variables were measured approximately fortnightly and continuously throughout the experiment duration. At the end of experiment number and yield of fishes were measured and survival rates were calculated. Survival rate of bighead carp and yield of common carp and bighead carp of variant 1 were significantly higher than those of variant 2. The yield of bighead carp larvae did not, while that of common carp, grass carp and total fish yield correlated significantly and positively with plankton primary production. The yield of accidentally fallen into ponds of crucian carps (Carassius carassiusLin. correlated strongly negatively with 1+/2+ common carps, which was indication for the strong food completion between them.

Roumen K. Kalchev

2009-06-01

199

Co-assessment of biomass and soil organic carbon stocks in a future reservoir area located in Southeast Asia.  

Science.gov (United States)

An assessment of the organic carbon stock present in living or dead vegetation and in the soil on the 450 km2 of the future Nam Theun 2 hydroelectric reservoir in Lao People's Democratic Republic was made. Nine land cover types were defined on the studied area: dense, medium, light, degraded, and riparian forests; agricultural soil; swamps; water; and others (roads, construction sites, and so on). Their geographical distribution was assessed by remote sensing using two 2008 SPOT 5 images. The area is mainly covered by dense and light forests (59%), while agricultural soil and swamps account for 11% and 2%, respectively. For each of these cover types, except water, organic carbon density was measured in the five pools defined by the Intergovernmental Panel on Climate Change: aboveground biomass, litter, deadwood, belowground biomass, and soil organic carbon. The area-weighted mean carbon densities for these pools were estimated at 45.4, 2.0, 2.2, 3.4, and 62.2 tC/ha, respectively, i.e., a total of about 115±15 tC/ha for a soil thickness of 30 cm, corresponding to a total flooded organic carbon stock of 5.1±0.7 MtC. This value is much lower than the carbon density for some South American reservoirs for example where total organic carbon stocks range from 251 to 326 tC/ha. It can be mainly explained by (1) the higher biomass density of South American tropical primary rainforest than of forests in this study and (2) the high proportion of areas with low carbon density, such as agricultural or slash-and-burn zones, in the studied area. PMID:20364314

Descloux, Stéphane; Chanudet, Vincent; Poilvé, Hervé; Grégoire, Alain

2011-02-01

200

ASSESSING HEAVY METALS IN THE WATERS, FISH AND MACROINVERTEBRATES IN MANILA BAY, PHILIPPINES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study assessed the heavy metals particularly total cadmium, total lead and total chromium in the waters, fish and macroinvertebrates in Manila Bay, Philippines. The heavy metals monitoring in the waters of Manila Bay were carried out for six consecutive months, September to February of 2007-2008, covering both wet and dry periods. The collection of fishes and macroinvertebrates in this investigation lasted from September to November 2007. Results showed that the heavy metals particular...

ARNOLD HALLARE; JOSEFINA DE JESUS; ELENA RAGRAGIO; TESSA PAULA ALCANTARA; KRISTINE JOY MARTILLANO; GLENN SIA SU; GLICERIA RAMOS

2009-01-01

 
 
 
 
201

DEVELOPMENT OF A FISH INDEX OF BIOTIC INTEGRITY FOR ASSESSING WADEABLE STREAMS IN WEST VIRGINIA  

Science.gov (United States)

We used Environmental Monitoring Assessment Program (EMAP) data from the Mid-Atlantic Highlands Assessment (MAHA) to develop an Index of Biotic Integrity (IBI) for West Virginia (WV). Standard techniques were used to evaluate a candidate pool of 58 fish assemblage metrics. Resp...

202

Life Cycle Assessment of Fish Culture in Thailand: Case Study of Nile Tilapia and Striped Catfish  

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Full Text Available This study was aimed to assess environmental impacts of fish culturing in Thailand using life cycle assessment (LCA method. The scope was a cradle-to-gate study of red nile tilapia (Oreochromis niloticus and striped catfish (Pangasianodon hypophthalmus. The impact assessment method of CML Baseline 2000 was applied to evaluate the impacts in the categories of abiotic depletion, acidification and global warming. The impacts of red nile tilapia were 3-4 times higher than those of striped catfish. The global warming potential of red nile tilapia was 2.96 kg CO2 eq, where as that of striped catfish was 1.01 kg CO2 eq. The feeds, especially fish meal, were the main impact contributors. Small replacement of fish meal with soybean meal while maintaining the growth rate of the fish was possible. This leaded to slightly decrease in the environmental impacts. The environmental performance of fish meal itself should be improved in order to reduce the impacts from fish culture.

Patcharaporn Pongpat

2013-10-01

203

Assessment of physiological strain in inland fishing activity  

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Full Text Available Ten fishermen aged between 19 and 48 years of age, were examined in the field during inland fishing activity, which they perform individually. Physiological strain in terms of heart rate varied between 86 and 115 beats/min with mean net cardiac cost of 32 beats/min. The average relative cardiac cost was 36%. Analysis of physiological responses revealed that the recommended limits of cardiac strain indices were surpassed during the majority of the fishing period. Average energy cost was estimated to be 3.3 kcal.min-1, which was about 34% of the VO2max. Average intensity of the workload entailed in the whole fishing shift appeared to be moderate and acceptable. Furthermore, the heat load in the working situation did not appear to be a serious threat to the health of the workers. Analysis of work revealed more static exertions in the work. To reduce the postural load and musculoskeletal discomforts of the fishermen, ergonomic interventions are required, which represents a further scope of study.

Biswas R

2006-01-01

204

Large-scale assessment of Mediterranean marine protected areas effects on fish assemblages.  

Science.gov (United States)

Marine protected areas (MPAs) were acknowledged globally as effective tools to mitigate the threats to oceans caused by fishing. Several studies assessed the effectiveness of individual MPAs in protecting fish assemblages, but regional assessments of multiple MPAs are scarce. Moreover, empirical evidence on the role of MPAs in contrasting the propagation of non-indigenous-species (NIS) and thermophilic species (ThS) is missing. We simultaneously investigated here the role of MPAs in reversing the effects of overfishing and in limiting the spread of NIS and ThS. The Mediterranean Sea was selected as study area as it is a region where 1) MPAs are numerous, 2) fishing has affected species and ecosystems, and 3) the arrival of NIS and the northward expansion of ThS took place. Fish surveys were done in well-enforced no-take MPAs (HP), partially-protected MPAs (IP) and fished areas (F) at 30 locations across the Mediterranean. Significantly higher fish biomass was found in HP compared to IP MPAs and F. Along a recovery trajectory from F to HP MPAs, IP were similar to F, showing that just well enforced MPAs triggers an effective recovery. Within HP MPAs, trophic structure of fish assemblages resembled a top-heavy biomass pyramid. Although the functional structure of fish assemblages was consistent among HP MPAs, species driving the recovery in HP MPAs differed among locations: this suggests that the recovery trajectories in HP MPAs are likely to be functionally similar (i.e., represented by predictable changes in trophic groups, especially fish predators), but the specific composition of the resulting assemblages may depend on local conditions. Our study did not show any effect of MPAs on NIS and ThS. These results may help provide more robust expectations, at proper regional scale, about the effects of new MPAs that may be established in the Mediterranean Sea and other ecoregions worldwide. PMID:24740479

Guidetti, Paolo; Baiata, Pasquale; Ballesteros, Enric; Di Franco, Antonio; Hereu, Bernat; Macpherson, Enrique; Micheli, Fiorenza; Pais, Antonio; Panzalis, Pieraugusto; Rosenberg, Andrew A; Zabala, Mikel; Sala, Enric

2014-01-01

205

Probabilistic framework for assessing the arsenic exposure risk from cooked fish consumption.  

Science.gov (United States)

Geogenic arsenic (As) contamination of groundwater is a major ecological and human health problem in southwestern and northeastern coastal areas of Taiwan. Here, we present a probabilistic framework for assessing the human health risks from consuming raw and cooked fish that were cultured in groundwater As-contaminated ponds in Taiwan by linking a physiologically based pharmacokinetics model and a Weibull dose-response model. Results indicate that As levels in baked, fried, and grilled fish were higher than those of raw fish. Frying resulted in the greatest increase in As concentration, followed by grilling, with baking affecting the As concentration the least. Simulation results show that, following consumption of baked As-contaminated fish, the health risk to humans is ratios of liver and lung cancers are generally acceptable at risk ranging from 10(-6) to 10(-4), the consumption of baked As-contaminated fish is unlikely to pose a significant risk to human health. However, contaminated fish cooked by frying resulted in significant health risks, showing the highest cumulative incidence ratios of liver cancer. We also show that males have higher cumulative incidence ratio of liver cancer than females. We found that although cooking resulted in an increase for As levels in As-contaminated fish, the risk to human health of consuming baked fish is nevertheless acceptable. We suggest the adoption of baking as a cooking method and warn against frying As-contaminated fish. We conclude that the concentration of contaminants after cooking should be taken into consideration when assessing the risk to human health. PMID:24804830

Ling, Min-Pei; Wu, Chiu-Hua; Chen, Szu-Chieh; Chen, Wei-Yu; Chio, Chia-Pin; Cheng, Yi-Hsien; Liao, Chung-Min

2014-12-01

206

Mercury contamination in human hair and fish from Cambodia: levels, specific accumulation and risk assessment  

International Nuclear Information System (INIS)

Mercury (Hg) concentrations in human hair and fish samples from Phnom Penh, Kien Svay, Tomnup Rolork and Batrong, Cambodia, collected in November 1999 and December 2000 were determined to understand the status of contamination, and age- and sex-dependent accumulation in humans and to assess the intake of mercury via fish consumption. Mercury concentrations in human hair ranged from 0.54 to 190 ?g/g dry wt. About 3% of the samples contained Hg levels exceeding the no observed adverse effects level (NOAEL) of WHO (50 ?g/g) and the levels in some hair samples of women also exceeded the NOAEL (10 ?g/g) associated with fetus neurotoxicity. A weak but significant positive correlation was observed between age and Hg levels in hair of residents. Mercury concentrations in muscle of marine and freshwater fish from Cambodia ranged from <0.01 to 0.96 ?g/g wet wt. Mercury intake rates were estimated on the basis of the Hg content in fish and daily fish consumption. Three samples of marine fish including sharp-tooth snapper and obtuse barracuda, and one sample of sharp-tooth snapper exceeded the guidelines by US EPA and by Joint FAO/WHO Expert Committee on Food Additives (JECFA), respectively, which indicates that some fish specimens examined (9% and 3% for US EPA and JECFA guidelines, respectively) were hazardous for consumption at the ingestion rate of Cambodian people (32.6 g/day). It is suggested that fish is probably the main source of Hg for Cambodian people. However, ext Hg for Cambodian people. However, extremely high Hg concentrations were observed in some individuals and could not be explained by Hg intake from fish consumption, indicating some other contamination sources of Hg in Cambodia. - A source other than fish may be responsible for high Hg in some Cambodians

207

Combination of optical and LiDAR satellite imagery with forest inventory data to improve wall-to-wall assessment of growing stock in Italy  

Science.gov (United States)

The acquisition of information about growing stock is a fundamental step in the framework of forest management planning and scenario modeling, besides being essential for assessing the amount of carbon stored within forest ecosystems. Gallaun et al. (2010) produced a pan-European map of forest growing stock by the combination of ground and remotely sensed data. The first objective of the current paper is to assess the accuracy of this map versus the ground data collected during the latest Italian National Forest Inventory (INFC). Next, a new wall-to-wall estimation of growing stock is obtained by combining ground measurements of four regional forest inventories with the CORINE land cover map of Italy and the global canopy height map derived from Geoscience Laser Altimeter System (GLAS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. More particularly, the growing stock measurements of the four inventories are stratified by ecosystem type and extended over all Italian forest areas through the application of locally weighted regressions to the GLAS/MODIS canopy height map. When compared to the INFC measurements, the new map shows higher accuracy than that by Gallaun et al., particularly for high growing stock values. The coefficient of determination between estimated and INFC growing stocks is improved by about 0.5, whilst the mean square error is reduced from 90 to 48 m3 ha-1.

Maselli, F.; Chiesi, M.; Mura, M.; Marchetti, M.; Corona, P.; Chirici, G.

2014-02-01

208

Development of a spatially distributed model of fish population density for habitat assessment of rivers  

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Flow conditions play an important role in sustaining biodiversity of river ecosystem. However, their relations to freshwater fishes, especially to fish population density, have not been clearly described. This study, therefore, aimed to propose a new methodology to quantitatively link habitat conditions, including flow conditions and other physical conditions, to population density of fish species. We developed a basin-scale fish distribution model by integrating the concept of habitat suitability assessment with a distributed hydrological model (DHM) in order to estimate fish population density with particular attention to flow conditions. Generalized linear model (GLM) was employed to evaluate the relationship between population density of fish species and major environmental factors. The target basin was Sagami River in central Japan, where the river reach was divided into 10 sections by estuary, confluences of tributaries, and river-crossing structures (dams, weirs). The DHM was employed to simulate river discharge from 1998 to 2005, which was used to calculate 10 flow indices including mean discharge, 25th and 75th percentile discharge, duration of low and high flows, number of floods. In addition, 5 water quality parameters and 13 other physical conditions (such as basin area, river width, mean diameter of riverbed material, and number of river-crossing structures upstream and downstream) of each river section were considered as environmental variables. In case of Sagami River, 10 habitat variables among them were then selected based on their correlations to avoid multicollinearity. Finally, the best GLM was developed for each species based on Akaike's information criterion. As results, population densities of 16 fish species in Sagami River were modelled, and correlation coefficients between observed and calculated population densities for 10 species were more than 0.70. The key habitat factors for population density varied among fish species. Minimum discharge (MID) was found to be positively correlated to 9 among 16 fish species. For duration of high and low flows (DHF and DLF), longer DHF/DLF was corresponded to lower population density for 7/6 fish species, respectively, such as Rhinogobius kurodai and Plecoglossus altivelis altivelis. Among physical habitat conditions, sinuosity index (SI, the ratio between actual river section length and straight line length) seems to be the most important parameter for fish population density in Sagami River basin, since it affects 12 out of 16 fish species, followed by mean longitudinal slope (S) and number of downstream dams (NLD). Above results demonstrated the applicability of fish distribution model to provide quantitative information on flow conditions required to maintain fish population, which enabled us to evaluate and project ecological consequences of water resource management policy, such as flood management and water withdrawal.

Sui, Pengzhe; Iwasaki, Akito; Ryo, Masahiro; Saavedra, Oliver; Yoshimura, Chihiro

2013-04-01

209

Risk–benefit evaluation of fish from Chinese markets: Nutrients and contaminants in 24 fish species from five big cities and related assessment for human health  

International Nuclear Information System (INIS)

The risks and benefits of fish from markets in Chinese cities have not previously been fully evaluated. In the present study, 24 common fish species with more than 400 individual samples were collected from markets from five big Chinese cities in 2007. The main nutrients and contaminants were measured and the risk–benefit was evaluated based on recommended nutrient intakes and risk level criteria set by relevant authorities. The comprehensive effects of nutrients and contaminants in marine oily fish were also evaluated using the data of two related human dietary intervention trials performed in dyslipidemic Chinese men and women in 2008 and 2010, respectively. The results showed that concentrations of contaminants analyzed including DDT, PCB7, arsenic and cadmium were much lower than their corresponding maximum limits with the exception of the mercury concentration in common carp. Concentrations of POPs and n-3 LCPUFA, mainly EPA and DHA, were positively associated with the lipid content of the fish. With a daily intake of 80–100 g marine oily fish, the persistent organic pollutants in fish would not counteract the beneficial effects of n-3 LCPUFA in reducing cardiovascular disease (CVD) risk markers. Marine oily fish provided more effective protection against CVD than lean fish, particularly for the dyslipidemic populations. The risk–benefit assessment based on the present daily aquatic product intake in Chinese urban residents (44.9 and 62.3 g for tban residents (44.9 and 62.3 g for the average values for all cities and big cities, respectively) indicated that fish, particularly marine oily fish, can be regularly consumed to achieve optimal nutritional benefits from n-3 LCPUFA, without causing significant contaminant-related health risks. However, the potential health threat from contaminants in fish should still be emphasized for the populations consuming large quantities of fish, particularly wild fish. - Highlights: ? We collected 24 fish species with more than 400 individual samples from five big Chinese cities. ? The health risk–benefit was evaluated based on the nutrients and contaminants content in fish. ? Two human trials were performed to evaluate the effects of contaminated fish on CVD prevalence. ? Contaminants in these fish couldn't alleviate the benefits of fish n-3 LCPUFA in CVD prevention. ? These fish in China can be regularly consumed without causing contaminant-related health risks.

210

Risk-benefit evaluation of fish from Chinese markets: Nutrients and contaminants in 24 fish species from five big cities and related assessment for human health  

Energy Technology Data Exchange (ETDEWEB)

The risks and benefits of fish from markets in Chinese cities have not previously been fully evaluated. In the present study, 24 common fish species with more than 400 individual samples were collected from markets from five big Chinese cities in 2007. The main nutrients and contaminants were measured and the risk-benefit was evaluated based on recommended nutrient intakes and risk level criteria set by relevant authorities. The comprehensive effects of nutrients and contaminants in marine oily fish were also evaluated using the data of two related human dietary intervention trials performed in dyslipidemic Chinese men and women in 2008 and 2010, respectively. The results showed that concentrations of contaminants analyzed including DDT, PCB{sub 7}, arsenic and cadmium were much lower than their corresponding maximum limits with the exception of the mercury concentration in common carp. Concentrations of POPs and n-3 LCPUFA, mainly EPA and DHA, were positively associated with the lipid content of the fish. With a daily intake of 80-100 g marine oily fish, the persistent organic pollutants in fish would not counteract the beneficial effects of n-3 LCPUFA in reducing cardiovascular disease (CVD) risk markers. Marine oily fish provided more effective protection against CVD than lean fish, particularly for the dyslipidemic populations. The risk-benefit assessment based on the present daily aquatic product intake in Chinese urban residents (44.9 and 62.3 g for the average values for all cities and big cities, respectively) indicated that fish, particularly marine oily fish, can be regularly consumed to achieve optimal nutritional benefits from n-3 LCPUFA, without causing significant contaminant-related health risks. However, the potential health threat from contaminants in fish should still be emphasized for the populations consuming large quantities of fish, particularly wild fish. - Highlights: Black-Right-Pointing-Pointer We collected 24 fish species with more than 400 individual samples from five big Chinese cities. Black-Right-Pointing-Pointer The health risk-benefit was evaluated based on the nutrients and contaminants content in fish. Black-Right-Pointing-Pointer Two human trials were performed to evaluate the effects of contaminated fish on CVD prevalence. Black-Right-Pointing-Pointer Contaminants in these fish couldn't alleviate the benefits of fish n-3 LCPUFA in CVD prevention. Black-Right-Pointing-Pointer These fish in China can be regularly consumed without causing contaminant-related health risks.

Du, Zhen-Yu, E-mail: zdu@nifes.no [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway); Zhang, Jian [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway); Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, 100050 (China); Department of Biomedicine, University of Bergen (Norway); Wang, Chunrong; Li, Lixiang; Man, Qingqing [Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, 100050 (China); Lundebye, Anne-Katrine; Froyland, Livar [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway)

2012-02-01

211

Species and global change-assessing the extinction point of albacore stocks  

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Full Text Available Global change determines the environmental condition and leads to decide the carrying capacity. While carrying capacity determines the extinction of the species, it is an important issue to estimate the extinction point of the species, the minimal carrying capacity, or the tolerant limitation of the species. If it is possible to estimate the tolerant limitation of the species, it will be possible to control the global change. Applied the above idea to the albacore stocks, it revealed that extinction point was about 0.0018% of the present status. From these results, it implies that this method may also suitable to other species for estimating their carrying capacities.

Shyh-Bin Wang

2012-07-01

212

A cost-efficient method to assess carbon stocks in tropical peat soil  

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Full Text Available Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m?3; Cd as a function of bulk density (gC cm?3; Bd, which can be used to rapidly estimate belowground carbon storage using Bd measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (Cd = Bd × 495.14 + 5.41, R2 = 0.93, n = 151 for soils with organic C content > 40%. As organic C content decreases, the relationship between Cd and Bd becomes less predictable as soil texture becomes an important determinant of Cd. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm?3, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation Cd = Bd × 468.76 + 5.82, with R2 = 0.95 and n = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease Cd estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%.

M. W. Warren

2012-11-01

213

Datos recientes de la distribución de la siembra de especies exóticas como base de la producción pesquera en aguas interiores mexicanas / Recent data on the distribution of the exotic species used in Mexican freshwater fisheries based on fish stocking  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Durante los años 2001-2009, el gobierno federal produjo 780 millones de crías pertenecientes a 22 taxa que se sembraron en cuerpos de agua interiores. El principal propósito de esta siembra fue la repoblación con fines pesqueros. Mediante información del mismo gobierno, se analiza la relación produc [...] ción-siembra de crías de los Centros Piscícolas federales y su efecto en la producción pesquera estatal en aguas interiores mexicanas. Se plantea que esta producción está relacionada con la siembra de crías que llevó a cabo la Comisión Nacional de Acuacultura y Pesca (CONAPESCA), organismo desconcentrado del gobierno federal. Lo anterior fue revisado al analizar la correspondencia entre la densidad de crías sembradas y los rendimientos pesqueros estatales. De los 22 taxa, 19 son especies de peces (7 nativas) y 2 son subespecies, 2 son anfibios nativos y 1 es un crustáceo malayo. En promedio, en el lapso, se sembraron anualmente 86.7 ± 37.9 millones de crías, de las que el 90% son tilapias y carpas, y sólo el 3% son especies nativas. La relación siembra/ha vs producción/ha muestra que a mayor densidad de siembra, se obtiene mayor rendimiento pesquero hasta alcanzar un valor asintótico. Si bien, el gobierno federal tiene actualmente por política no sembrar en cuerpos de agua naturales especies exóticas, éstas permanecen de siembras anteriores, o las siembran los gobiernos estatales o son de cultivos privados. Abstract in english Federal government produced around 780 millions of fry belonging to 22 taxa during 2001-2009 which were stocked in Mexican reservoirs basically to enhance fisheries. With official information from the federal fisheries agency CONAPESCA stocking-production analysis for the fish farms from the federal [...] government was studied at state level. We review stocking-yield relationship at state level. From the 22 taxa: 19 are fish (7 native species) and 2 subspecies; 2 native amphibious and 1 Malay crustacean. Production mean for nine-year period was 86.7 ± 37.9 millions of fry, 90% of which were tilapias and carps while only 3% were native species. Stocking/ha vs Yield/ha were clearly related, thus at more stocking rate more production was obtained arriving to an asintotic value. At present, federal government policy don’t allow to stock exotic species in natural water bodies, nevertheless they stay there because of previous or local stocking events.

Ana L., Ibáñez; Héctor, Espinosa-Pérez; José L., García-Calderón.

214

Farmed fish welfare-suffering assessment and impact on product quality  

Directory of Open Access Journals (Sweden)

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.

Bianca Maria Poli

2010-01-01

215

Statistical assessment of fish behavior from split-beam hydro-acoustic sampling  

International Nuclear Information System (INIS)

Statistical methods are presented for using echo-traces from split-beam hydro-acoustic sampling to assess fish behavior in response to a stimulus. The data presented are from a study designed to assess the response of free-ranging, lake-resident fish, primarily kokanee (Oncorhynchus nerka) and rainbow trout (Oncorhynchus mykiss) to high intensity strobe lights, and was conducted at Grand Coulee Dam on the Columbia River in Northern Washington State. The lights were deployed immediately upstream from the turbine intakes, in a region exposed to daily alternating periods of high and low flows. The study design included five down-looking split-beam transducers positioned in a line at incremental distances upstream from the strobe lights, and treatments applied in randomized pseudo-replicate blocks. Statistical methods included the use of odds-ratios from fitted loglinear models. Fish-track velocity vectors were modeled using circular probability distributions. Both analyses are depicted graphically. Study results suggest large increases of fish activity in the presence of the strobe lights, most notably at night and during periods of low flow. The lights also induced notable bimodality in the angular distributions of the fish track velocity vectors. Statistical/SUMmaries are presented along with interpretations on fish behavior

216

Main meiofauna taxa as an indicator for assessing the spatial and seasonal impact of fish farming.  

Science.gov (United States)

The present study aimed to establish potential indicators of fish farming pollution in muddy substrate, by means of meiofauna, and to test whether the effect of the fish farm is more important to determine the meiofauna community than the seasonal environmental conditions. Sampling was performed in spring, after several months of light feeding, and in summer, at high food supply. Samples were collected in three directions at various distances from the floating cages. Harpacticoid copepods and kinorhynchs, whose abundance decreased under the cages, were put forward as indicator taxa. However, harpacticoid copepods were sensitive to fish farm only, while kinorhynchs showed responsiveness to fish farm and to seasonal environmental conditions. Total meiofauna density was dependent on season sensu stricto. The nMDS clearly showed a 'cage community' and 'control community' in both sampling occasions; therefore it is a good tool for impact assessment. PMID:19394971

Grego, M; De Troch, M; Forte, J; Malej, A

2009-08-01

217

Assessment of the Impact of Extension Services on Fish Farming in Ekiti State, Nigeria  

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Full Text Available The study was carried out to assess the impact of access to extension services on fish farming in Ekiti State, Nigeria. Specifically, the study investigated the socio–economic characteristics of fish farmers, information disseminated to fish farmers, attributes of extension agents, and farmers’ access to extension services and farmers profitability. A well-structured questionnaire was used to collect information from the farmers and a sample size of 90 fish farmers was selected from the six local government selected. Analysis of data was carried out using frequency and percentage tables and Gross Margin analysis was used to determine the profitability of the farmers. There was relationship between farmers’ access to extension services and their profitability. It was recommended that extension agents should intensify their efforts in reaching farmers and passing useful information to them in order to increase farmers’ profitability.

Agbebi, F. O.

2012-03-01

218

Towards Integration of Environmental and Health Impact Assessments for Wild Capture Fishing and Farmed Fish with Particular Reference to Public Health and Occupational Health Dimensions  

Directory of Open Access Journals (Sweden)

Full Text Available The paper offers a review and commentary, with particular reference to the production of fish from wild capture fisheries and aquaculture, on neglected aspects of health impact assessments which are viewed by a range of international and national health bodies and development agencies as valuable and necessary project tools. Assessments sometimes include environmental health impact assessments but rarely include specific occupational health and safety impact assessments especially integrated into a wider public health assessment. This is in contrast to the extensive application of environmental impact assessments to fishing and the comparatively large body of research now generated on the public health effects of eating fish. The value of expanding and applying the broader assessments would be considerable because in 2004 the United Nations Food and Agriculture Organization reports there were 41,408,000 people in the total ‘fishing’ sector including 11,289,000 in aquaculture. The paper explores some of the complex interactions that occur with regard to fishing activities and proposes the wider adoption of health impact assessment tools in these neglected sectors through an integrated public health impact assessment tool.

Andrew Watterson

2008-12-01

219

Fishing industry borrows from natural capital at high shadow interest rates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fish stocks can be considered as natural capital stocks providing harvestable fish. Fishing at low stock sizes means borrowing from the natural asset. While fishing a particular quantity generates immediate profits and income, an interest rate has to be paid in terms of foregone future fishing income, as the fish stock's reproductive capacity remains low and fishing costs stay high. In this paper we propose to apply the concept of shadowinterest rate to quantify the degree of overfishing. It ...

Quaas, Martin F.; Froese, Rainer; Herwartz, Helmut; Requate, Till; Schmidt, Jo?rn O.; Voss, Ru?diger

2012-01-01

220

Taking Stock and Taking Steps: The Case for an Adolescent Version of the Short-Assessment of Risk and Treatability  

Science.gov (United States)

The field of violence risk assessment has matured considerably, possibly advancing beyond its own adolescence. At this point in the field’s evolution, it is more important than ever for the development of any new device to be accompanied by a strong rationale and the capacity to provide a unique contribution. With this issue in mind, we first take stock of the field of adolescent risk assessment in order to describe the rapid progress that this field has made, as well as the gaps that led us to adapt the Short-Term Assessment of Risk and Treatability (START; Webster, Martin, Brink, Nicholls, & Desmarais, 2009) for use with adolescents. We view the Short-Term Assessment of Risk and Treatability: Adolescent Version (START:AV; Nicholls, Viljoen, Cruise, Desmarais, & Webster, 2010; Viljoen, Cruise, Nicholls, Desmarais, & Webster, in progress) as complementing other risk measures in four primary ways: 1) rather than focusing solely on violence risk, it examines broader adverse outcomes to which some adolescents are vulnerable (including self-harm, suicide, victimization, substance abuse, unauthorized leave, self-neglect, general offending); 2) it places a balanced emphasis on adolescents’ strengths; 3) it focuses on dynamic factors that are relevant to short-term assessment, risk management, and treatment planning; and 4) it is designed for both mental health and justice populations. We describe the developmentally-informed approach we took in the adaptation of the START for adolescents, and outline future steps for the continuing validation and refinement of the START:AV. PMID:23436982

Viljoen, Jodi L.; Cruise, Keith R.; Nicholls, Tonia L.; Desmarais, Sarah L.; Webster, Christopher

2012-01-01

 
 
 
 
221

The Assessment of Social Reporting on behalf of Accepted Corporations Listed in Tehran Stock Exchange  

Directory of Open Access Journals (Sweden)

Full Text Available During the recent years that many changes have accomplished in economy and social expectations, typically the accounting world has confronted the society with the socio-environmental effects of industries development. According to these changes in society and environment, accounting also affects from it s environment. In this study the feasibility of social reporting on behalf of accepted corporations listed in Tehran stock exchange has been studied. In this survey we accumulate required data about corporations using a questionnaire and due to the obviousness of statistical population size to estimate the sample size. Conclusions of research indicate that factors such as lack of appropriate accounting information system, lack of awareness of managers about the social cost and nonexistence of legal standards and high social reporting costs causes the avoidance of social reporting on behalf of Iranian corporations.

Hosseyn Karbasi Yazdi

2012-07-01

222

TRANSECT FISH DATA FOR SOUTH FLORIDA ECOSYSTEM ASSESSMENT PROJECT  

Science.gov (United States)

The South Florida Ecosystem Assessment Project is an innovative, large-scale monitoring and assessment program designed to measure current and changing conditions of ecological resources in South Florida using an integrated holistic approach. This data set contains results for f...

223

Stream fishes and desirable fish stocks  

DEFF Research Database (Denmark)

Freshwater fi sh communities have always been valuable resources for society, particularly the species that migrate between freshwater and the sea. Historically, eel, salmon and trout were so abundant that good fi shing luck could turn a capable fi sherman into a wealthy person. Unfortunately, migrating fi sh became threatened by over-fi shing quite early in human history. The more recent construction of dams and other habitat destruction associated with development of towns, industries and intensive agriculture have reduced populations further. The largest Danish river, the River Gudenå, illustrates this historical decline and also the diffi culty of re-establishing healthy fi sh communities once the original populations have deteriorated or, in the case of salmon, become extinct. Efforts are currently needed to be made to effectively restore and manage fi sh communities in streams.

Dieperink, C.; Sand-Jensen, K.

2006-01-01

224

Impact of entrainment and impingement on fish populations in the Hudson River Estuary. Volume II. Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass spawning stock, and the LMS real-time life cycle model  

Energy Technology Data Exchange (ETDEWEB)

This volume includes a series of four exhibits relating to impacts of impingement on fish populations, together with a collection of critical evaluations of testimony prepared for the utilities by their consultants. The first exhibit is a quantitative evaluation of four sources of bias (collection efficiency, reimpingement, impingement on inoperative screens, and impingement survival) affecting estimates of the number of fish killed at Hudson River power plants. The two following exhibits contain, respectively, a detailed assessment of the impact of impingement on the Hudson River white perch population and estimates of conditional impingement mortality rates for seven Hudson River fish populations. The fourth exhibit is an evaluation of the engineering feasibility and potential biological effectiveness of several types of modified intake structures proposed as alternatives to cooling towers for reducing impingement impacts. The remainder of Volume II consists of critical evaluations of the utilities' empirical evidence for the existence of density-dependent growth in young-of-the-year striped bass and white perch, of their estimate of the age-composition of the striped bass spawning stock in the Hudson River, and of their use of the Lawler, Matusky, and Skelly (LMS) Real-Time Life Cycle Model to estimate the impact of entrainment and impingement on the Hudson River striped bass population.

Barnthouse, L. W.; Van Winkle, W.; Golumbek, J.; Cada, G. F.; Goodyear, C. P.; Christensen, S. W.; Cannon, J. B.; Lee, D. W.

1982-04-01

225

Impact of entrainment and impingement on fish populations in the Hudson River Estuary. Volume II. Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass spawning stock, and the LMS real-time life cycle model  

International Nuclear Information System (INIS)

This volume includes a series of four exhibits relating to impacts of impingement on fish populations, together with a collection of critical evaluations of testimony prepared for the utilities by their consultants. The first exhibit is a quantitative evaluation of four sources of bias (collection efficiency, reimpingement, impingement on inoperative screens, and impingement survival) affecting estimates of the number of fish killed at Hudson River power plants. The two following exhibits contain, respectively, a detailed assessment of the impact of impingement on the Hudson River white perch population and estimates of conditional impingement mortality rates for seven Hudson River fish populations. The fourth exhibit is an evaluation of the engineering feasibility and potential biological effectiveness of several types of modified intake structures proposed as alternatives to cooling towers for reducing impingement impacts. The remainder of Volume II consists of critical evaluations of the utilities' empirical evidence for the existence of density-dependent growth in young-of-the-year striped bass and white perch, of their estimate of the age-composition of the striped bass spawning stock in the Hudson River, and of their use of the Lawler, Matusky, and Skelly (LMS) Real-Time Life Cycle Model to estimate the impact of entrainment and impingement on the Hudson River striped bass population

226

Blood chemistry profile of Surubim hybrid fish (Pseudoplatystoma reticulatum X P. corruscans raised in different stocking densities Perfil bioquímico do híbrido de Surubim (Pseudoplatystoma reticulatum X P. corruscans criado em diferentes densidades  

Directory of Open Access Journals (Sweden)

Full Text Available Massive production, such as fish growing in water recirculation system, imposes challenges to animals capable of altering their homeostatic balance, and is able to affect their physiological performance. Therefore, the levels of ions and serum enzymes can be used as indicators of fish health. This study aimed to analyze the blood biochemistry profile of hybrid surubim (P. reticulatum X P. corruscans submitted to different stocking densities in water recirculation system, in two distinct stages of production, from 150 to 400 g (first trial, and 400 to 1000 g (second trial. In the first trial, the five stocking rates were: 27.5, 47.5, 67.5, 87.5 and 107.5 fish/m³ of water. To obtain these densities, it was used 11, 19, 27, 35 and 43 fish per tank, respectively. In the second trial, five stocking rates were: 10, 20, 30, 40 and 50 fish/m³ of water. To obtain these densities we used 4, 8, 12, 16 and 20 fish per tank, respectively. The concentrations of glucose, cholesterol, triglycerides, urea, creatinine, alkaline phosphatase (ALP, aspartate aminotransferase (AST, lactate dehydrogenase (LDH, calcium, phosphorus, potassium and magnesium were obtained. Only urea concentrations in first trial and ALP and AST concentrations in second trial were influenced by stocking density, presenting a significant difference between groups. Thus, in both trials the hybrid fish studied maintained homeostasis when reared in different stocking densities.Dentre os sistemas de produção, o de recirculação de água impõe desafios para os animais que podem ser capazes de alterar o seu equilíbrio homeostático, afetando o índice de desempenho. Por conseguinte, os níveis de ions e enzimas séricas podem ser utilizados como indicadores de saúde dos peixes. Neste estudo, objetivo-se analisar o perfil de bioquímico do sangue do híbrido de Surubim (P. reticulatum X P. corruscans, submetido a diferentes densidades de estocagem em sistema de recirculação de água, em duas fases distintas de produção, de 150 a 400 g (primeiro ensaio e, 400 a 1000 g (segundo ensaio. No primeiro ensaio, as cinco densidades de estocagem estudadas foram: 27,5, 47,5, 67,5, 87,5 e 107,5 peixes/m³ de água. Para a obtenção dessas densidades foram utilizados 11, 19, 27, 35 e 43 peixes por tanque, respectivamente. No segundo ensaio, as cinco densidades de estocagem estudadas foram: 10, 20, 30, 40 e 50 peixes/m³ de água. Para a obtenção dessas densidades foram utilizados 4, 8, 12, 16 e 20 peixes por tanque, respectivamente. As concentrações de glicose, colesterol, triglicérides, ureia, creatinina, fosfatase alcalina (FA, aspartato aminotransferase (AST, desidrogenase lática (LDH, cálcio, fósforo, potássio e magnésio foram avaliadas. Apenas as concentrações de ureia no primeiro ensaio e FA e AST no segundo ensaio foram influenciadas pela densidade de estocagem, apresentando uma diferença significativa entre os grupos. Assim, em ambos os ensaios, o Surubim híbrido manteve a homeostase do sangue em diferentes densidades.

Carla Rosa Labarrère

2013-06-01

227

Assessment on dioxin-like compounds intake from various marine fish from Zhoushan Fishery, China.  

Science.gov (United States)

Sea fish consuming is an important intake source of dioxin-like compounds, especially for the coastal residents. To assess the intake levels of these contaminants from sea fish and to provide risk-based consumption advice, concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in 32 commonly consumed fish species from Zhoushan Fishery, China. Due to the different accumulation influenced by fat content, feed habits and living zone in the sea area, the levels of PCDDs, PCDFs and dl-PCBs in different fish species varied significantly ranging from 0.002 to 0.078pg WHO-TEQ/g fresh weight, from 0.002 to 0.553pg WHO-TEQ/g fresh weight and from 0.003 to 2.059pg WHO-TEQ/g fresh weight, respectively. Based on mean fish consuming rate in China, the estimated maximum possible dioxin-like compounds intake through different fish species ranged from 0.26 to 65.61pgTEQkg(-1)bwmonth(-1). Bullet mackerel has the highest monthly intake level which was much higher than other fish species and very close to the provisional tolerable monthly intake (70pgTEQkg(-)(1)bwmonth(-)(1)) proposed by the Joint FAO/WHO Expert Committee on Food Additives. Hence, comparing to other fish species, the consumption of Bullet mackerel from Zhoushan Fishery should be cautious to reduce the potential health risk. PMID:25180652

Wang, Xiangyong; Zhang, Hongxia; Zhang, Lei; Zhong, Kai; Shang, Xiaohong; Zhao, Yunfeng; Tong, Zhendong; Yu, Xinwei; Li, Jingguang; Wu, Yongning

2015-01-01

228

Reproductive effects assessment of fish in streams on the Oak Ridge Reservation  

International Nuclear Information System (INIS)

The Department of Energy has three large facilities located on the Oak Ridge Reservation Site, the Y-12 Plant, and the Oak Ridge National Laboratory. Several Biological Monitoring and Abatement Programs (BMAP) monitor and assess the effects of these facilities on the aquatic and terrestrial resources of the reservation. One BMAP task concerns the potential role of contaminant-related reproductive dysfunction in shaping the composition of fish communities in creeks draining the facilities. This task addresses specific questions concerning (1) the reproductive competence of adult fish in the streams, and (2) the capacity of fish embryos and fry to survive and develop sequent reproductive cohorts. Evidence for current or potential reproductive impacts in several of the streams include abnormal fecundity at some sites, increased incidences of oocyte atresia, and a marked toxicity of surface water samples from several stream reaches to fish embryos in periodic embryo-larval tests. Recovery of certain of the monitored streams in response to ongoing remedial actions is documented by positive changes over time in many these indicators of reproductive dysfunction. These results suggest that the monitoring of reproductive indicators can be a sensitive tool for assessing the effects of both industrial discharges and remedial activities on the fish resources of receiving streams

229

Assessment of consequences of notifiable fish disease incursions in England and Wales  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A consequence assessment framework was developed to evaluate the economic and environmental consequences of an exotic disease in the context of supporting policy level decisions on mitigation strategies. The framework adopted a semi-qualitative analysis of impacts supported by expert judgement. The efficacy of the framework was illustrated via assessment of the notifiable fish disease, Gyrodactylus salaris. In this example, the economic cost of an illustrative outbreak of G. salaris ranged fr...

Morant, M. P.; Prpich, George; Peeler, E.; Thrush, M.; Rocks, Sophie A.; Pollard, Simon J. T.

2013-01-01

230

A Comparative Assessment of Hydroponically Grown Cereal Crops for the Purification of Aquaculture Wastewater and the Production of Fish Feed  

Directory of Open Access Journals (Sweden)

Full Text Available Hydroponically grown wheat, barley and oats were examined for their ability to remove nutrients from aquaculture wastewater. Wheat, barley and oats seeds were germinated in water in a hydroponics system. The seedlings then received wastewater from an aquaculture system stocked with Arctic charr. During the experiment, the crops grew rapidly and fairly uniformly and showed no signs of mineral deficiency although fungal growth was evident. The average crop heights and yields at harvest were 19.0, 25.5 and 25.2 cm and 64, 59 and 42 t ha-1 for wheat, barley and oats, respectively. The hydroponically grown wheat, barley and oats were able to significantly reduce the pollution load of the aquaculture wastewater. The TS, COD, NH4+-N, NO2--N, NO3--N and PO43--P reductions ranged from 53.3 to 57.7%, from 55.7 to 78.7%, from 76.0 to 80.0% from 85.1 to 92.9%, from 62.1 to 79.3% and from 74.1 to 93.0%, respectively. The compartments containing barley produced the highest quality effluent, which was suitable for reuse in aquaculture operations. The average TS, COD, NH4+-N, NO2--N, NO3--N and PO43--P concentrations and pH of the final effluent from the compartments containing barley were 442, 64, 0.50, 0.02, 5.89 and 0.61 mg L-1 and 6.65, respectively. The nutritive value of the three wastewater grown crops was assessed to determine the suitability of using the plants as a component in fish feed. The three terrestrial crops meet the energy, fat, Ca, Mg, P, Na, S and Mn dietary requirements of aquatic animals, exceed the carbohydrate, crude fiber, Cl, K, Cu, Fe, Se and Zn requirements of fish and shellfish and do not contain sufficient amounts of protein to meet the dietary requirements of fish and shellfish. The crops will require supplementation with a high protein source that contains low concentrations of carbohydrates, crude fiber, Cl, K, Cu, Fe, Se and Zn. Common protein sources that could be used for supplementation included fishmeal, bone meal and blood meal.

A. M. Snow

2008-01-01

231

An evaluation of multi-annual management strategies for ICES roundfish stocks  

DEFF Research Database (Denmark)

Current scientific management objectives for ICES roundfish stocks are to ensure conservation of the biological resource and do not explicitly consider economic or social objectives. For example, there are currently no objectives to maximize the sustainable yield or to reduce variability in total allowable catches (TACs). This is despite the fact that the current system can result in wide annual fluctuations in TAC, limiting the ability of the fishing industry to plan for the future. Therefore, this study evaluated management strategies that stabilized catches by setting bounds on the interannual variability in TACs. An integrated modelling framework was used, which simulated both the real and observed systems and the interactions between system components. This allowed the evaluation of candidate management strategies with respect to the intrinsic properties of the systems, as well as our ability to observe, monitor, assess, and control them. Strategies were evaluated in terms of risk (measured as the probability of spawning-stock biomass falling below a biomass threshold for the stock) and cumulative yield. In general, bounds on interannual TAC change of 10% and 20% affected the ability to achieve management targets, although the outcome of applying TAC bounds could not have been pre-judged because results were highly dependent on the specific biology of the stock, current status, and the interaction with assessment and management. For example, for North Sea haddock, management became less responsive to fluctuations resulting from large recruitment events. Simulated target fishing mortality levels were rarely achieved, regardless of the TAC bound applied, and actual fishing mortality rates oscillated around the target. In the longer term, more restrictive bounds resulted in oscillations of greater amplitude and wavelength in yield and SSB. Bounds had less effect when a stock was close to the biomass corresponding to the target F. Risk for stocks that are declining or currently at low abundance may be greater, because if bounds restrict the extent to which TACs can be reduced each year, they could lead to collapse of the stock and the loss of all future revenue. However, for a recovered stock or one at high abundance, the loss of yield as a result of bounds would be smaller than that caused by the total collapse of the fishery. At low stock size or if the stock was declining, catches should be changed more rapidly than when the stock was increasing or at a high level, especially high stock sizes acting as an insurance against uncertainty. Therefore, rebuilding strategies, and strategies aimed at maintaining the stock above prescribed limits, should be considered separately. (c) 2005 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved.

Ulrich, Clara

2006-01-01

232

Carbon stock assessment of three selected agroforestry systems in Bukidnon, Philippines  

Directory of Open Access Journals (Sweden)

Full Text Available Climate change, caused by global warming, is a phenomenon partly resulting from abundance of carbon dioxide in the atmosphere.It is the most pressing environmental problem of the world today. It persists, and it cannot be stopped. Rather, it can be mitigated. Agroforestrysystems as land use can reduce the atmospheric concentration of carbon dioxide. This study therefore aimed to generate data on the carbonstocks of three selected agroforestry systems located within the Province of Bukidnon. The methodologies used include measurement of treesat diameter breast height (dbh and sampling of herbaceous vegetation, litter, and soil for carbon content determination and farmer interview.Results showed that carbon accumulation of agroforestry systems goes along with the following order: taungya agroforestry system (174 MgCha-1 > mixed multistorey system (162 MgC ha-1 > falcata-coffee multistorey system (92 MgC ha-1. Carbon was stored in the various pools inthe following order of magnitude: soil (77-92% > trees (7-22% > herbaceous vegetation and litter (1%. Compared with natural forests, theseselected agroforestry systems represents 23-44% of the total carbon stock. Policy programs promoting the establishment of agroforestry systemsin idle lands in Bukidnon should be considered.

Mildred M. Labata

2012-06-01

233

Carbon stock assessment of two agroforestry systems in a tropical forest reserve in the Philippines  

Energy Technology Data Exchange (ETDEWEB)

Carbon dioxide is the most abundant greenhouse gas (GHG) that causes global warming. Thus, land uses such as an agroforestry system have a significant role in moderating climate change since they can be sources and sinks of carbon. The aim of the study was to generate data on the carbon stocks of two agroforestry systems, specifically a Gmelina arborea-Theobroma cacao multistorey system and an alley cropping system with Gliricidia sepium hedges at the agroforestry research and demonstration area inside a forest reserve in Southern Luzon, Philippines. The multistorey system had a mean biomass of 258 Mg C ha{sup -1} and a carbon density of 185 Mg C ha{sup -1}. Carbon was stored in the various pools in the following order of magnitude: soil > tree biomass (above-ground) > necromass > understorey vegetation > roots. The Gliricidia hedgerow had a biomass density of 3.8 Mg C ha{sup -1}; total carbon density was 93 Mg C ha{sup -1}, of which 92 Mg C ha{sup -1} was in the soil.

Lasco, R.D.; Sales, R.F.; Estrella, R.; Saplaco, S.R.; Castillo, A.S.A.; Cruz, R.V.O.; Pulhin, F.B. [University of Philippines Los Banos, Laguna (Philippines). College of Forestry & Natural Resources Environmental Forestry Programme

2001-07-01

234

Population dynamics and stock assessment for Octopus maya (Cephalopoda:Octopodidae) fishery in the Campeche Bank, Gulf of Mexico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: English Abstract in spanish Octopus maya es uno de los recursos pesqueros más importantes del Golfo de México, con rendimientos anuales promedio de 9 000 t, y constituye el 80% de la captura total, seguido por O. vulgaris. En la pesquería participan dos flotas artesanales sobre O. maya, y una de mediana altura capturando ambas [...] especies. Datos de frecuencia de longitudes de la captura para la temporada de pesca 1994 (Agosto 1° a Diciembre 15) fueron usados para analizar la dinámica poblacional y el estado de explotación de O. maya. Los parámetros del modelo de von Bertalanffy fueron: L° = 252 mm longitud de manto, K = 1.4 años-1, C = 1.0 y WP = 0.6, y tZ = 0.842 años. Una estimación inicial de la mortalidad natural fue M = 2.2, la mortalidad total Z = 8.77, y tasa de explotación F/Z = 0.75, lo cual sugiere una intensa explotación. El análisis de rendimiento por recluta indica que podría aumentarse la talla mínima legal para incrementar los rendimientos. El VPA indica un recurso explotado al límite de su capacidad biológica. Debido a que las hembras mueren después de la reproducción, una nueva estimación de mortalidad natural, M = 3.3, y tasa de explotación, F/Z = 0.57 fueron obtenidas, coincidiendo con los resultados del VPA basado en longitudes y el método de Thompson y Bell. Abstract in english The octopus (Octopus maya) is one of the most important fish resources in the Mexican Gulf of Mexico with a mean annual yield of 9000 ton, and a reasonable number of jobs created; O. maya represents 80% of the total octopus catch, followed by Octopus vulgaris. There are two artisanal fleets based on [...] Octopus maya and a middle-size fleet that covers both species. Catch-at-length structured data from the artisanal fleets, for the 1994 season (August 1st to December 15th) were used to analyze the O. maya population dynamics and stock and to estimate the current level of exploitation. Von Bertalanffy growth parameters were: L = 252 mm, mantle length; K=1.4 year -1; oscillation parameters C=1.0, WP=0.6; and tz=0.842 years. A rough estimate of natural mortality was M=2.2, total mortality from catch curve Z=8.77, and exploitation rate F/Z=0.75. This last value suggests an intensive exploitation, even when yield per recruit analysis indicates both fleets may increase the minimum legal size on about 10% to increase yields. The length-based VPA also shows that the stock is being exploited under its maximum acceptable biological limit. These apparently contradictory results are explained by biological and behavioral characteristics of this species. Because most females die after reproduction, a new gross estimation of natural mortality was computed as M=3.3. The new estimate of exploitation rate was F/Z=0.57. This new value coincides with results from the length-VPA and the Thompson and Bell methods, the former suggesting that a reduction of 20% in fishing mortality may provide larger yields. This fishery resource is fully exploited and current management measures must be revised to sustain and probably optimize yields.

Francisco, Arreguín-Sánchez; Manuel J, Solís -Ramírez; María E, González de la Rosa.

235

Population dynamics and stock assessment for Octopus maya (Cephalopoda:Octopodidae fishery in the Campeche Bank, Gulf of Mexico  

Directory of Open Access Journals (Sweden)

Full Text Available The octopus (Octopus maya is one of the most important fish resources in the Mexican Gulf of Mexico with a mean annual yield of 9000 ton, and a reasonable number of jobs created; O. maya represents 80% of the total octopus catch, followed by Octopus vulgaris. There are two artisanal fleets based on Octopus maya and a middle-size fleet that covers both species. Catch-at-length structured data from the artisanal fleets, for the 1994 season (August 1st to December 15th were used to analyze the O. maya population dynamics and stock and to estimate the current level of exploitation. Von Bertalanffy growth parameters were: L = 252 mm, mantle length; K=1.4 year -1; oscillation parameters C=1.0, WP=0.6; and tz=0.842 years. A rough estimate of natural mortality was M=2.2, total mortality from catch curve Z=8.77, and exploitation rate F/Z=0.75. This last value suggests an intensive exploitation, even when yield per recruit analysis indicates both fleets may increase the minimum legal size on about 10% to increase yields. The length-based VPA also shows that the stock is being exploited under its maximum acceptable biological limit. These apparently contradictory results are explained by biological and behavioral characteristics of this species. Because most females die after reproduction, a new gross estimation of natural mortality was computed as M=3.3. The new estimate of exploitation rate was F/Z=0.57. This new value coincides with results from the length-VPA and the Thompson and Bell methods, the former suggesting that a reduction of 20% in fishing mortality may provide larger yields. This fishery resource is fully exploited and current management measures must be revised to sustain and probably optimize yields.Octopus maya es uno de los recursos pesqueros más importantes del Golfo de México, con rendimientos anuales promedio de 9 000 t, y constituye el 80% de la captura total, seguido por O. vulgaris. En la pesquería participan dos flotas artesanales sobre O. maya, y una de mediana altura capturando ambas especies. Datos de frecuencia de longitudes de la captura para la temporada de pesca 1994 (Agosto 1° a Diciembre 15 fueron usados para analizar la dinámica poblacional y el estado de explotación de O. maya. Los parámetros del modelo de von Bertalanffy fueron: L° = 252 mm longitud de manto, K = 1.4 años-1, C = 1.0 y WP = 0.6, y tZ = 0.842 años. Una estimación inicial de la mortalidad natural fue M = 2.2, la mortalidad total Z = 8.77, y tasa de explotación F/Z = 0.75, lo cual sugiere una intensa explotación. El análisis de rendimiento por recluta indica que podría aumentarse la talla mínima legal para incrementar los rendimientos. El VPA indica un recurso explotado al límite de su capacidad biológica. Debido a que las hembras mueren después de la reproducción, una nueva estimación de mortalidad natural, M = 3.3, y tasa de explotación, F/Z = 0.57 fueron obtenidas, coincidiendo con los resultados del VPA basado en longitudes y el método de Thompson y Bell.

Francisco Arreguín-Sánchez

2000-06-01

236

USEPA REGION 10 REGIONAL ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM: FISH  

Science.gov (United States)

The USEPA designed and implemented the Environmental Assessment Program (EMAP) to determine the current status, extent, changes, and trends in indicators of the condition of the Nations ecological resources on regional and national scales with known confidence. USEPA Region 10s ...

237

Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume III. An analysis of the validity of the utilities' stock-recruitment curve-fitting exercise and prior estimation of beta technique. Environmental Sciences Division publication No. 1792  

Energy Technology Data Exchange (ETDEWEB)

This report addresses the validity of the utilities' use of the Ricker stock-recruitment model to extrapolate the combined entrainment-impingement losses of young fish to reductions in the equilibrium population size of adult fish. In our testimony, a methodology was developed and applied to address a single fundamental question: if the Ricker model really did apply to the Hudson River striped bass population, could the utilities' estimates, based on curve-fitting, of the parameter alpha (which controls the impact) be considered reliable. In addition, an analysis is included of the efficacy of an alternative means of estimating alpha, termed the technique of prior estimation of beta (used by the utilities in a report prepared for regulatory hearings on the Cornwall Pumped Storage Project). This validation methodology should also be useful in evaluating inferences drawn in the literature from fits of stock-recruitment models to data obtained from other fish stocks.

Christensen, S. W.; Goodyear, C. P.; Kirk, B. L.

1982-03-01

238

Wavelet Transform-Based Approach for Assess the Relationships between Stock Markets of Developed Countries and MENA Region  

Directory of Open Access Journals (Sweden)

Full Text Available This study develops an economic tool that investigates the relationship between the two developed stock market indices of the United States and the United Kingdom and the ten stock market indices of the Middle East and North Africa (MENA countries. The work is accomplished through a novel technique of combining wavelet filtering and the VEC model. Discrete wavelet filtering is used to eliminate noise in the daily dataset which covers the period from June 29, 2001 to May 5, 2009. The series generated by the discrete wavelet transform is then analyzed to determine the long-and short-term relationships between the stock markets by using a cointegration test and a VEC model. Results of the comparison between the proposed and traditional models demonstrate that the former (DWT with VEC model outperforms the latter (VEC model in performance and fitting the financial stock market series; furthermore, the former provides real information on the relationships among the stock markets. The cointegration test affirms the existence of cointegration between the studied series and a long-term relationship between the United States and United Kingdom stock markets and the MENA stock markets. The proposed model also shows the existence of a short-term relationship between the stock markets of the United States and the United Kingdom and the three stock markets of MENA region: Istanbul, UAE and Morocco.

Amel Abdoullah Ahmed

2014-01-01

239

Problems of stock definition in estimating relative contributions of Atlantic striped bass to the coastal fishery  

Science.gov (United States)

Stock contribution studies of mixed-stock fisheries rely on the application of classification algorithms to samples of unknown origin. Although the performance of these algorithms can be assessed, there are no guidelines regarding decisions about including minor stocks, pooling stocks into regional groups, or sampling discrete substocks to adequately characterize a stock. We examined these questions for striped bass Morone saxatilis of the U.S. Atlantic coast by applying linear discriminant functions to meristic and morphometric data from fish collected from spawning areas. Some of our samples were from the Hudson and Roanoke rivers and four tributaries of the Chesapeake Bay. We also collected fish of mixed-stock origin from the Atlantic Ocean near Montauk, New York. Inclusion of the minor stock from the Roanoke River in the classification algorithm decreased the correct-classification rate, whereas grouping of the Roanoke River and Chesapeake Bay stock into a regional (''southern'') group increased the overall resolution. The increased resolution was offset by our inability to obtain separate contribution estimates of the groups that were pooled. Although multivariate analysis of variance indicated significant differences among Chesapeake Bay substocks, increasing the number of substocks in the discriminant analysis decreased the overall correct-classification rate. Although the inclusion of one, two, three, or four substocks in the classification algorithm did not greatly affect the overall correct-classification rates, the specific combination of substocks significantly affected the relative contribution estimates derived from the mixed-stock sample. Future studies of this kind must balance the costs and benefits of including minor stocks and would profit from examination of the variation in discriminant characters among all Chesapeake Bay substocks.

Waldman, John R.; Fabrizio, Mary C.

1994-01-01

240

Fish-based groups for ecological assessment in rivers: the importance of environmental drivers on taxonomic and functional traits of fish assemblages  

Directory of Open Access Journals (Sweden)

Full Text Available The use of river-types is of practical value, serving as groups for which assessment procedures can be developed and applied. An abiotic typology was set by the Portuguese Water Agency, mainly based on 6 major morphoclimatic regions. However, to be biologically meaningful, this typology should fit the distribution patterns of the biological quality elements communities proposed in Water Framework Directive under the lowest possible human pressure. This study aimed to identify and characterize fish-based geographical groups for continental Portugal and their environmental and geographical discriptors, using taxonomic and functional traits. Sampling took place between 2004 and 2006 during Spring. Fish fauna from 155 reference sites was analysed using a multivariate approach. Cluster Analysis on fish composition identified 10 fish-groups, expressing a clear correspondence to the river basin level, due to the restrict basin distribution of many species. Groups showed a wider aggregation in 4 regions with a larger geographical correspondence, statistically supported by Similarity Analysis, both on fish composition and mostly on fish metrics/guilds. Principal Components Analysis revealed major environmental drivers associated to fish-groups and fish-regions. Fish-groups were hierarchically grouped over major and local regions, expressing a large-scale response to a North-South environmental gradient defined by temperature, precipitation, mineralization and altitude, and a regional scale response mainly to drainage area and flow discharge. From North to South, fish-regions were related to the morphoclimatic regions. Results contributed to reduce redundance in abiotic river-types and set the final typology for Portuguese rivers, constituting a fundamental tool for planning and managing water resources.

Matono P.

2012-06-01

 
 
 
 
241

DDT in fishes from four different Amazon sites: exposure assessment for breast feeding infants  

Energy Technology Data Exchange (ETDEWEB)

Concerning DDT in food, based on clinical observations as well as experimental animals, the annual Joint FAO/WHO Meetings on Pesticide Residues held in 2000 estimated a Provisional Tolerable Daily Intake (PTDI) for DDT in 0.01 mg/kg/day. Marien and Laflamme have proposed a Tolerable Daily Intake (TDI) for breast feedings infants of 5 x 10{sup -3} mg/kg/day, and conducted an assessment to evaluate the public health significance of eating {sigma}ODDT contaminated fish, accomplished by establishing a daily intake level of DDT for the population of greatest concern, like breastfeeding infants. Their results indicated that mothers who frequently consume contaminated fish could have breast milk DDT concentrations highly enough to expose their infants to levels above the TDI. The aim of this study was to evaluate the ODDT (o,p'-DDT + p,p'-DDT + o,p'-DDE + p,p'-DDE + o,p'-DDD) levels in commercial fish samples from distinct Brazilian Amazon sites, which are consumed by the riverine populations, and to assess the potential health impacts from eating these fishes, especially for breastfeeding infants.

D' Amato, C.; Torres, J.P.; Malm, O. [Lab. de Radioisotopos Eduardo Penna Franca, Inst. de Biofisica, UFRJ, RJ (Brazil); Bastos, W. [Lab. de Biogeoquimica, UNIR, Porto Velho (Brazil); Claudio, L.; Markowitz, S. [International Training Program on Environmental and Occupational Health, Mount Sinai School of Medicine, Queens Coll., NY (United States)

2004-09-15

242

Risk assessment in airlines stocks market / Avaliação do risco no mercado de ações de companhias aéreas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste trabalho foram comparados os resultados entre carteiras de ações de companhias aéreas Norte-americanas e Europeia. O modelo avalia o risco de mercado utilizando a abordagem do Value-at-Risk em ambas às carteiras ao longo de um mês. A análise foi realizada através do uso dos métodos GARCH-EVT e [...] t-Student Copula com simulação de Monte Carlo. Os ativos do mercado financeiro costumam apresentar caudas pesadas em suas distribuições probabilísticas, portanto, um processo de modelagem capaz de lidar com esse aspecto é fundamental para mensurar o risco de perda dos investimentos. Foi analisado o período de meados de 2007 até meados de 2012 para compor uma comparação entre as duas carteiras. A crise financeira deflagrada em 2008 teve um maior impacto nas ações do mercado Norte Americano quando em relação ao mercado Europeu. A participação central dos transportes na economia faz com que estudos de avaliação do risco de investimento nesse setor sejam cruciais no processo de desenvolvimento industrial. A volatilidade do risco nesse mercado ocorre tanto por motivos internos e externos ao setor da aviação e o aprimoramento metodológico das ferramentas financeiras pode oferecer uma importante contribuição devido a dependência dos fluxos de investimentos. Abstract in english In this paper we compared the results between stock portfolios of North American and European airlines. The model accesses the market risk using Value-at-Risk approach in both portfolios over one month period. The analysis was performed through the use of GARCH-EVT methods and Student's-t Copula wit [...] h a Monte Carlo Simulation. The assets in the financial market usually present heavy tails in their probability distributions, so, a process capable to deal with this issue is crucial to measure the risk of loss. We analyzed the period from mid-2007 to mid-2012 to compose comparison between these two portfolios. The financial crisis of 2008 had a great impact in the North America market in relative to the European market. The central role of transport in the economy makes studies dealing with investment risk measure in this sector crucial for the industrial development. The volatility of risk in the airline market happens by internal and external motives and the methodological development of financial tools can offer an important contribution due the investment flux dependency.

Renato Cesar, Sato.

2013-04-01

243

Radiological assessment of fish samples due to natural radionuclides in river Yobe, Northern Nigeria  

International Nuclear Information System (INIS)

Assessment of natural radioactivity of some fish samples in river Yobe was conducted, using gamma spectroscopy method with NaI(TI) detector. Radioactivity is phenomenon that leads to production of radiations, whereas radiation is known to trigger or induce cancer. The fish were analyzed to estimate the radioactivity (activity) concentrations due to natural radionuclides 226Ra, 232Th and 40K. The obtained result show that the activity concentration for (226Ra), in all the fish samples collected ranges from 15.23±2.45BqKg-1 to 67.39±2.13BqKg-1 with an average value of 34.13±1.34BqKg-1. That of 232Th, ranges from 42.66±0.81BqKg-1 to 201.18±3.82BqKg-1, and the average value stands at 96.01±3.82BqKg-1. The activity concentration for 40K, ranges between 243.3±1.56 BqKg-1 to 618.2±2.81 BqKg-1 and the average is 413.92±1.7 BqKg-1. This study indicated that average daily intake due to natural activity from the fish is valued at 0.913 Bq/day, 2.577Bq/day and 11.088 Bq/day for 226Ra, 232Th and 40K respectively. This shows that the activity concentration values for fish, shows a promising result with most of the fish activity concentrations been within the acceptable limits. However locations (F02, F07 and F12), fish became outliers with significant values of 112.53?Svy-1, 121.11?Svy-1 and 114.32?Svy-1 effective dose. This could be attributed to variation in geological formations within the river as well as the feeding habits of these fish. The work shows that consumers of fish from River Yobe have no risk of radioactivity ingestion, even though no amount of radiation is assumed to be totally safe.

244

Stock Assessment of Columbia River Anadromous Salmonids : Final Report, Volume I, Chinook, Coho, Chum and Sockeye Salmon Summaries.  

Energy Technology Data Exchange (ETDEWEB)

The purpose was to identify and characterize the wild and hatchery stocks of salmon and steelhead in the Columbia River Basin on the basis of currently available information. This report provides a comprehensive compilation of data on the status and life histories of Columbia Basin salmonid stocks.

Howell, Philip J.

1986-07-01

245

Schoolhouse stock.  

Science.gov (United States)

Texas does not require schools to stock epinephrine unless it's prescribed for a specific student. Texas allergists are now fighting to pass legislation that would force schools to stock unassigned epinephrine injectors so that coaches, school nurses, and other trained staff could immediately treat students who suffer a severe and unexpected allergic reaction. PMID:25416833

Nuzback, Kara

2014-01-01

246

Predation risk assessment by olfactory and visual cues in a coral reef fish  

Science.gov (United States)

Assessment of predation risk is vital for the success of an individual. Primary cues for the assessment include visual and olfactory stimuli, but the relative importance of these sources of information for risk assessment has seldom been assessed for marine fishes. This study examined the importance of visual and chemical cues in assessing risk for the star goby, Asterropteryx semipunctatus. Visual and chemical cue intensities were used that were indicative of a high threat situation. The behavioural response elicited by both the visual cues of a predator (the rock cod, Cephalopholis boenak) and the chemical alarm cues from conspecifics were similar in magnitude, with responses including a decrease in feeding strikes and moves. A bobbing behaviour was exhibited when the predator was visible and not when only exposed to the chemical alarm cue. When visual and chemical cues were presented together they yielded a stronger antipredator response than when gobies were exposed solely to conspecific alarm cues. This suggests additivity of risk assessment information at the levels of threat used, however, the goby’s response is also likely to depend on the environmental and social context of the predator-prey encounter. This study highlights the importance of chemical cues in the assessment of predation risk for a coral reef fish.

McCormick, M. I.; Manassa, R.

2008-03-01

247

Assessing the efficacy of single-pass backpack electrofishing to characterize fish community structure  

Science.gov (United States)

Two-pass backpack electrofishing data collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess the efficacy of single-pass backpack electrofishing. A two-capture removal model was used to estimate, within 10 river basins across the United States, proportional fish species richness from one-pass electrofishing and probabilities of detection for individual fish species. Mean estimated species richness from first-pass sampling (p??s1) ranged from 80.7% to 100% of estimated total species richness for each river basin, based on at least seven samples per basin. However, p??s1 values for individual sites ranged from 40% to 100% of estimated total species richness. Additional species unique to the second pass were collected in 50.3% of the samples. Of these, cyprinids and centrarchids were collected most frequently. Proportional fish species richness estimated for the first pass increased significantly with decreasing stream width for 1 of the 10 river basins. When used to calculate probabilities of detection of individual fish species, the removal model failed 48% of the time because the number of individuals of a species was greater in the second pass than in the first pass. Single-pass backpack electrofishing data alone may make it difficult to determine whether characterized fish community structure data are real or spurious. The two-pass removal model can be used to assess the effectiveness of sampling species richness with a single electrofishing pass. However, the two-pass removal model may have limited utility to determine probabilities of detection of individual species and, thus, limit the ability to assess the effectiveness of single-pass sampling to characterize species relative abundances. Multiple-pass (at least three passes) backpack electrofishing at a large number of sites may not be cost-effective as part of a standardized sampling protocol for large-geographic-scale studies. However, multiple-pass electrofishing at some sites may be necessary to better evaluate the adequacy of single-pass electrofishing and to help make meaningful interpretations of fish community structure.

Meador, M. R.; McIntyre, J. P.; Pollock, K. H.

2003-01-01

248

Desarrollo de un marco Bayesiano para la valoración del stock y el análisis de decisión de la pesquería del erizo rojo en Baja California, México / Developing a Bayesian framework for stock assessment and decision analysis of the red sea urchin fishery in Baja California, Mexico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish La pesquería del erizo rojo (Strongylocentrotus franciscanus) es importante para la economía de Baja California (México). Su pesca comercial se inició a principios de los años 70 como resultado de la expansión de su mercado de exportación; sin embargo, se ha detectado una baja sustancial en sus capt [...] uras y abundancia desde 1986. Dada la falta de un índice de abundancia relativa independiente de la pesquería para todas las áreas de captura, se utilizaron datos de CPUE y captura para llevar a cabo una valoración del stock del erizo rojo y realizar un análisis de decisión con relación a su pesquería. La dinámica poblacional fue descrita mediante el modelo de biomasa excedente de Schaefer usando métodos Bayesianos para estimar los parámetros del modelo y para proyectar la dinámica poblacional de la especie bajo diferentes escenarios de manejo, los cuales incluyeron estrategias de tasas de explotación constantes y capturas constantes. Los resultados sugieren que el stock actual es sólo 17% de la bioma virgen y que, para una estrategia de captura constante, un incremento del 10% en el nivel de captura actual podría causar el colapso de la pesquería en 20 años. Los resultados de las simulaciones sugieren que una estrategia de tasa de explotación constante entre 15% y 25% causaría que la población se recuperara y la captura se maximizara en 2024. Mayores niveles de explotación incrementarían la probabilidad de que la biomasa sea menor al 40% de la capacidad de carga de la población. Abstract in english The red sea urchin (Strongylocentrotus franciscanus) fishery is of importance to the economy of Baja California (Mexico). The commercial fishery started in the early 1970s as a result of expanding export markets, but has experienced substantial decline in landings and abundance since 1986. Fishery-i [...] ndependent surveys have not been conducted for all fishing areas, thus CPUE and catch data were used to conduct a stock assessment and decision analysis for the red sea urchin stock. The red sea urchin population dynamics was described with the Schaefer biomass dynamic model. Bayesian approaches were used for the estimation of the model parameters and for projecting the population dynamics of the species under different management scenarios, including constant harvest rate and constant catch strategies. This study suggests that the current stock is only 17% of the virgin stock biomass and that, for a constant catch policy, a 10% increase in the current catch rate could potentially cause the collapse of the fishery in 20 years. Simulation results suggested that a constant harvest rate between 15% and 25% would cause the population to recover and maximize the catch in 2024. Higher harvest rate levels would increase the probability of the biomass being less than 40% of the population carrying capacity.

J, Jurado-Molina; JS, Palleiro-Nayar; NL, Gutiérrez.

2009-06-01

249

A scoring system approach for the parasite predictive assessment of fish lots: a proof of concept with anisakids.  

Science.gov (United States)

A total of 982 individuals distributed in 11 lots belonging to 10 fish species from three Atlantic FAO fishing areas were sampled and examined to detect the presence of anisakid larvae in fish muscle. After hazard identification by genetic sequencing and exposure assessment by anatomic extent and demographic characterization of infection, all data were fitted for each fish species to a new proposed scoring schema of parasite prediction. In the absence of a criterion standard method for inspection and precise definition of the quantum satis for parasites in contaminated fish lots, the inspection rating scheme called SADE (Site of infection, Assurance of quality, Demography, Epidemiology) may help fish industries to precisely handle and to evaluate the likely outcome of infected fish lots after being diagnosed. For this purpose, a supporting flow diagram for decision was defined and suggested. This new performance assessment tool has the aim of staging fish lots, thus helping in planning manufacture, commercial, and research decisions during self-management programs. This novel scoring system provides an improved inspection format by implementing the occurrence stratification for parasites to guide Hazard Analysis and Critical Control Points (HACCP) programs for the uniform exchange of information among fish industries, administration and researchers, thus facilitating standardization and communication. In the future, this scoring version could be validated (in terms of classification and wording) for similar overall predictive purposes in other muscular parasites infecting seafood products. PMID:24147656

Llarena-Reino, María; Abollo, Elvira; Pascual, Santiago

2013-12-01

250

Performance Assessment of the Food Industry of Tehran Stock Exchange Based on Balanced Score Card (BSC Technique  

Directory of Open Access Journals (Sweden)

Full Text Available Major objective of the present paper was to study the role of balanced score card regarding performance assessment of companies listed in food and beverage industry in the stock exchange. This survey is descriptive and is regarded as a quasi-experimental research plan (Ex-Post design. The statistical population included 200 managers and research sample consisted of 99 persons based on Cochran formula. Questionnaire was used for data collection. Frequency tables and appropriate diagrams were applied to describe data and inferential statistics methods such as student's t-test were used to confirm or reject hypotheses. Variance analysis and t-test for two independent samples were used to study the impact of personal characteristics on responding to the hypotheses. Ranking of improvement degree of indexes for realization of purposes and determining rank of each factor was studied using Friedman test. Results of testing hypotheses reveal it is necessary for organizations to emphasize internal processes more given that planning and implementing efficient and suitable processes in the organization is led to offering appropriate services. About growth and learning scope it is notable that since employees are major capitals of the organization, special attention must be paid to this sector in order to satisfy employees and provide long-term benefits of the organization.

Morteza Asadi

2013-04-01

251

Fish micronucleus assay to assess genotoxic potential of arsenic at its guideline exposure in aquatic environment.  

Science.gov (United States)

The exposure to arsenic, a potential genotoxic carcinogen in humans, via drinking water is a serious worldwide health hazard. The arsenic content of 10 ?g L(-1) in drinking water, however, has been established as its guideline standard (maximum contaminant limit) that has been estimated to pose minimum risk to cancer. Since micronucleus induction in the erythrocytes of fish is a sensitive indicator of genotoxic agents in water, the piscine micronucleus assay was used in the present experiment to assess the genotoxic potential of arsenic at its various exposure levels including the guideline value for drinking water. The experiments were conducted in two different species of fishes, the pond murrel (Channa punctatus) and the goldfish (Carassius auratus). Significant increases in the frequency of micronucleated erythrocytes were documented in a dose-dependent manner in both Channa and Carassius. The fishes, however, exhibited variations in inter-specific sensitivity to micronucleus induction following arsenic exposure. The exposure level of arsenic at its guideline value for drinking water, therefore, exhibited marked genotoxicity in fishes. PMID:23494554

Kumar, Amod; Kesari, Vibudh P; Khan, Parimal K

2013-04-01

252

ASSESSING HEAVY METALS IN THE WATERS, FISH AND MACROINVERTEBRATES IN MANILA BAY, PHILIPPINES  

Directory of Open Access Journals (Sweden)

Full Text Available This study assessed the heavy metals particularly total cadmium, total lead and total chromium in the waters, fish and macroinvertebrates in Manila Bay, Philippines. The heavy metals monitoring in the waters of Manila Bay were carried out for six consecutive months, September to February of 2007-2008, covering both wet and dry periods. The collection of fishes and macroinvertebrates in this investigation lasted from September to November 2007. Results showed that the heavy metals particularly total chromium, total lead and total cadmium were evident in the waters, fish and macroinvertebrates. Significant differences on the total cadmium and total lead in the waters were noted for both the wet and dry periods. Accumulation of heavy metals in the aquatic organisms was species dependent. Highest heavy metal concentrations among the tissues in the studied fishes were evident in the liver as compared to the muscle. Continuous heavy metals monitoring is encouraged to effectively analyze the risk and impact of heavy metals on the environment and on the general public’s welfare.

ARNOLD HALLARE

2009-12-01

253

Trace metal levels in water, fish, and sediment from River Nile, Egypt: potential health risks assessment.  

Science.gov (United States)

The purposes of this study were to describe the impact of metal pollution on the main economic fish species Tilapia nilotica and to assess the potential health risk from consuming this contaminated fish in Egypt. Trace metals, including Ag, Al, Cd, Bo, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, St, V, Zn, and As, were determined in water, Tilapia nilotica, and sediments from the River Nile, Domiate branch, Egypt. Metal concentrations in fish of Al, Cd, Co, Fe, Mn, Pb, V, and Zn (mg/kg dry weight [dw]) and concentrations in sediment of Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn (mg/kg dw) were above the International Atomic Energy Agency (IAEA-407) levels. However, trace metals in river water were still at permissible levels for Egyptian standards. The hazard index (HI) of estimated metal mixtures for intake of Tilapia nilotica (23.37) demonstrated that intake resulted in higher noncarcinogenic risk. In conclusion, the overall problem of metal contamination in fish collected from the River Nile was more serious than postulated to occur in an industrialized and densely populated area. In the light of known risks to public health, environmental protection laws are needed in Egypt. PMID:24283369

Dahshan, Hesham; Abd-Elall, Amr Mohamed Mohamed; Megahed, Ayman Mohamed

2013-01-01

254

Replacing fish meal by food waste in feed pellets to culture lower trophic level fish containing acceptable levels of organochlorine pesticides: Health risk assessments.  

Science.gov (United States)

The present study used food waste (collected from local hotels and restaurants) feed pellets in polyculture of low-trophic level fish [bighead (Aristichtys nobilis), grass carp (Ctenopharyngodon idellus), and mud carp (Cirrhina molitorella)] aiming at producing safe and quality products for local consumption. The results indicated that grass carp (hexachlorocyclohexanes (HCHs) waste feed pellets were relatively free of organochlorine pesticides (OCPs). The experimental ponds (water and sediment) were relatively free of OCPs, lowering the possibility of biomagnification of OCPs in the food chains within the ponds. The raw concentrations of OCPs extracted from the fish were not in the bioavailable form, which would ultimately reach bloodstream and exert adverse effects on human body. Health risk assessments based on digestible concentrations are commonly regarded as a more accurate method. The results of health risk assessments based on raw and digestible concentrations showed that the fish fed with food waste feed pellets were safe for consumption from the OCP perspective. PMID:25080070

Cheng, Zhang; Mo, Wing-Yin; Man, Yu-Bon; Nie, Xiang-Ping; Li, Kai-Bing; Wong, Ming-Hung

2014-12-01

255

Rapid Fishery Assessment by Market Survey (RFAMS) – An Improved Rapid-Assessment Approach to Characterising Fish Landings in Developing Countries  

Science.gov (United States)

The complex multi-gear, multi-species tropical fisheries in developing countries are poorly understood and characterising the landings from these fisheries is often impossible using conventional approaches. A rapid assessment method for characterising landings at fish markets, using an index of abundance and estimated weight within taxonomic groups, is described. This approach was developed for contexts where there are no detailed data collection protocols, and where consistent data collection across a wide range of fisheries types and geographic areas is required, regardless of the size of the site and scale of the landings. This methodology, which was demonstrated at seven fish landing sites/fish markets in southern Indonesia between July 2008 and January 2011, provides a rapid assessment of the abundance and diversity in the wild catch over a wide variety of taxonomic groups. The approach has wider application for species-rich fisheries in developing countries where there is an urgent need for better data collection protocols, monitoring future changes in market demographics, and evaluating health of fisheries. PMID:25275308

White, William T.; Last, Peter R.; Dharmadi; Faizah, Ria; Chodrijah, Umi; Buckworth, Rik C.; Dichmont, Catherine M.

2014-01-01

256

Taking stock of two decades of attachment transmission gap: broadening the assessment of maternal behavior.  

Science.gov (United States)

This report aimed to investigate the capacity of maternal behaviors tailored to children's attachment and exploration systems to jointly explain the well-known mother-child transmission of attachment. Four home visits were conducted between ages 7 months and 2 years with 130 mother-child dyads to assess maternal attachment state of mind, sensitivity, autonomy support, and mother-child attachment security. Results showed that together, maternal sensitivity and autonomy support fully accounted for the relation between maternal and child attachment, that they each accounted for a unique portion of this relation, and that the magnitude of these mediated pathways was equivalent. These results suggest that the attachment transmission gap can be narrowed by the use of a theory-driven multidimensional approach to maternal behavior. PMID:24611791

Bernier, Annie; Matte-Gagné, Célia; Bélanger, Marie-Ève; Whipple, Natasha

2014-09-01

257

Comparability of fish-based ecological quality assessments for geographically distinct Iberian regions.  

Science.gov (United States)

In this work we compare two Iberian and a pan-European fish-based methods to assess ecological quality in rivers: the Fish-based Index of Biotic Integrity for Portuguese Wadeable Streams (F-IBIP), the Mediterranean Index of Biotic Integrity (IBIMED) and the pan-European Fish Index (EFI+). The results presented herein were developed in the context of the 2nd phase of the Intercalibration Exercise (IC), as required by the Water Frame Directive (WFD). The IC is aimed at ensuring comparability of the quality boundaries among the different WFD assessment methods developed by the Member States for each biological quality element. Although the two national assessment methods were developed for very distinct regions of Iberia (Western and Eastern Iberian Peninsula) they share the same methodological background: both are type-specific and guild-based multimetric indices. EFI+ is a multimetric guild-based model, but it is site-specific and uses a predictive modelling approach. The three indices were computed for all sites included in the Iberian Intercalibration database to allow the direct comparison, by means of linear regressions, of the resulting three quality values per site. The quality boundary harmonization between the two Iberian methods was only possible through an indirect comparison between the two indices, using EFI+ as a common metric. The three indices were also shown to be responsive to a common set of human induced pressures. This study highlights the need to develop general assessment methods adapted to wide geographical ranges with high species turnover to help intercalibrating assessment methods tailored for geographically more restricted regions. PMID:24071063

Segurado, P; Caiola, N; Pont, D; Oliveira, J M; Delaigue, O; Ferreira, M T

2014-04-01

258

Evaluation of swimming capability and potential velocity barrier problems for fish. Part B: New telemetric approaches to the assessment of fish swimming performance  

International Nuclear Information System (INIS)

This report represents the second part of a study undertaken to develop information related to swimming capability of several important fish species. The study will provide biological design criteria to mitigate potential velocity barrier problems associated with hydroelectric power plants. This part of the report focuses on the development and evaluation of approaches to assessing locomotory activity, swimming performance and energy load costs to fish under naturally occurring conditions and in relation to potential barriers. The study involved implantation of a bio-sensitive radio transmitter (electromyogram (EMG)) tag in the swimming muscle of fish, calibration of locomotory ability and energetic scope, and subsequent use of EMG signals to assess swimming performance and metabolic costs in situ. Digital signal processing (DSP) with antennae switching was also used to study high speed swimming performance, behaviour, and migratory strategy in relation to ascent of an experimental flume. The techniques and technologies developed indicate the complexity of factors that regulate fish swimming energy expenditure that need to be considered in the design and operation of fish passage facilities. 84 refs., 6 tabs., figs., 2 appendices

259

Population Dynamics and Stock Assessment of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in the Coastal Area of Trang Province, Thailand  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The population dynamics and stock assessment of blue swimming crab (Portunus pelagicus Linnaeus, 1758) in the coastal area of Trang province, Southern Thailand was done through stratified sampling of 7,499 crabs that were caught by crab gill nets and crab traps. The sampling was done from September 2006 to August 2007. The carapace width and weight relationship was measured, including parameters such as asymptotic outer carapace width (OCWa), curvature (K), asymptotic i...

Songrak, Apirak; Sawusdee, Amonsak

2009-01-01

260

Assessing connectivity of estuarine fishes based on stable isotope ratio analysis  

Science.gov (United States)

Assessing connectivity is fundamental to understanding the population dynamics of fishes. I propose that isotopic analyses can greatly contribute to studies of connectivity in estuarine fishes due to the high diversity of isotopic signatures found among estuarine habitats and the fact that variations in isotopic composition at the base of a food web are reflected in the tissues of consumers. Isotopic analysis can be used for identifying nursery habitats and estimating their contribution to adult populations. If movement to a new habitat is accompanied by a shift to foods of distinct isotopic composition, recent immigrants and residents can be distinguished based on their isotopic ratios. Movement patterns thus can be reconstructed based on information obtained from individuals. A key consideration is the rate of isotopic turnover, which determines the length of time that an immigrant to a given habitat will be distinguishable from a longtime resident. A literature survey indicated that few studies have measured turnover rates in fishes and that these have focused on larvae and juveniles. These studies reveal that biomass gain is the primary process driving turnover rates, while metabolic turnover is either minimal or undetectable. Using a simple dilution model and biomass-specific growth rates, I estimated that young fishes with fast growth rates will reflect the isotopic composition of a new diet within days or weeks. Older or slower-growing individuals may take years or never fully equilibrate. Future studies should evaluate the factors that influence turnover rates in fishes during various stages of the life cycle and in different tissues, as well as explore the potential for combining stable isotope and otolith microstructure analyses to examine the relationship between demographic parameters, movement and connectivity.

Herzka, Sharon Z.

2005-07-01

 
 
 
 
261

Environmental Assessment for the Transfer of 1100 AREA, Southern Rail Connection and Rolling Stock, Hanford Site, Richland, Washington  

Energy Technology Data Exchange (ETDEWEB)

This environmental assessment (EA) has been prepared to assess potential environmental impacts associated with the U.S. Department of Energy's proposed action: the transfer of the 1100 Area, southern rail connection and rolling stock to a non-federal entity. Impact information contained herein will be used by the U.S. Department of Energy, Richland Operations Office Manager, to determine if the proposed action is a major federal action significantly affecting the quality of the human environment. If the proposed action is determined to be major and significant, an environmental impact statement will be prepared. If the proposed action is determined not to be major and significant, a Finding of No Significant Impact (FONSI) will be issued and the action can proceed. Criteria used to evaluate significance can be found in Title 40, Code of Federal Regulations (CFR) 1508.27. This EA was prepared in compliance with the ''National Environmental Policy Act'' (NEPA) of 1969, as amended, the Council on Environmental Quality (CEQ) Regulations for Implementing the Procedural Provisions of NEPA (40 CFR 1500-1508), and the U.S. Department of Energy Implementing Procedures for NEPA (10 CFR 1021). The following is a description of each section of the EA. (1) Purpose and Need for Action. This provides a brief statement concerning the problem or opportunity the U.S. Department of Energy is addressing with the proposed action. As necessary, background information is provided. (2) Description of the Proposed Action. A description with sufficient detail to identify potential environmental impacts is provided. (3) Alternatives to the Proposed Action. Reasonable alternative actions, which would address the Purpose and Need, are described. A no action alternative, as required by 10 CFR 1021, also is described. (4) Affected Environment. This provides a brief description of the locale in which the proposed action takes place, and which may be environmentally impacted. (5) Environmental Impacts. The range of environmental impacts, beneficial and adverse, are described for the proposed action. Impacts of alternatives briefly are discussed. (6) Permits and Regulatory Requirements. A brief description of permits and regulatory requirements for the proposed action is provided. (7) Organizations Consulted. Any outside agencies, groups, or individuals contacted as part of environmental assessment documentation preparation are listed. (8) References. Documents used to provide information or data are listed. The appendices contain additional information necessary to support an understanding of the proposed action, alternatives, and potential impacts is provided. Comments resulting from review of the environmental assessment by states and tribes or other stakeholders and the response to those comments will be included in the appendices.

N/A

1998-08-01

262

TOXICITY ASSESSMENT OF PHOSPHONIUM BASED IONIC LIQUIDS TOWARDS FEMALE GUPPY FISH  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, two phosphonium based ionic liquids (butyl triphenyl phosphonium chloride and hexyl triphenyl phosphonium bromide have been synthesized using quarternisation process. The toxicities of these Ionic Liquids (ILs are unknown and may be harmful to humans and the environment. Therefore, the toxicity assessment of these ILs was carried out according to the Organization for Economic Cooperation and Development (OECD 203 guideline using female guppy fish (Poecilia reticulata. The median Lethal Concentrations (LC50 have been estimated for butyl triphenyl phosphonium chloride and for hexyl triphenyl phosphonium bromide to be 73.35 and 61.36 mg L-1 respectively. Both LC50 obtained can be identified as slightly toxic ILs based on Acute Toxicity Rating Scale by Fish and Wildlife Service (FWS. The findings from this study can be used for better design of phosphonium-based ILs with consideration of their aquatic toxicities.

Mohanad El-Harbawi

2013-01-01

263

Submission of Danish Coastal Fish data to HELCOM FISH, for the Thematic Assessment : Data from six NOVANA stations 2006  

DEFF Research Database (Denmark)

Coastal fish communities are important components of Baltic Sea ecosystems. Coastal fish experts have been meeting on an annual basis since 2004 under the umbrella of HELCOM. In 2006, the expert group developed a metadatabase on monitoring activities, methods, parameters and species surveyed based on the data contained in the COBRA database. A GIS interactive map was subsequently created by HELCOM to improve access to the information in the metadatabase and to visualise coastal fish monitoring activities in the Baltic Sea. Link: http://www.helcom.fi/GIS/en_GB/coastalfishGIS/

Strand, Jakob

264

Elemental fish tissue contamination in northeastern U.S. lakes: Evaluation of an approach to regional assessment  

Energy Technology Data Exchange (ETDEWEB)

The approach of the Environmental Monitoring and Assessment Program (EMAP) to monitoring of fish tissue contaminants is shown to have utility for regional assessment, and for discrimination of regional from local contamination. The survey sampling design employed by EMAP can be used to make regional assessments without conducting a complete resource inventory. The Environmental Monitoring and Assessment Program--Surface Waters conducted a survey of 167 lakes in the northeastern United States during 1992 through 1994 and analyzed whole fish composite samples for contaminants, including Al, As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, and Zn. Using fish tissue contaminant consumption risk levels derived from US Environmental Protection Agency hazard assessment models, methylmercury (MeHg) was determined to be the elemental contaminant of regional concern to fish consumers: 26% of lakes contained fish with MeHg exceeding a human critical value of 0.2 {micro}g/g/ 54 and 98% of lakes contained fish with MeHg exceeding wildlife critical values for piscivorous mammals and birds, respectively. The other elements analyzed appeared to be at safe levels on a regional scale, or only of localized concern with regard to human health.

Yeardley, R.B. Jr. [SoBran, Inc., Cincinnati, OH (United States); Lazorchak, J.M. [Environmental Protection Agency, Cincinnati, OH (United States); Paulsen, S.G. [Environmental Protection Agency, Corvallis, OR (United States)

1998-09-01

265

Mitochondrial membrane potential is a suitable candidate for assessing pollution toxicity in fish  

Energy Technology Data Exchange (ETDEWEB)

Fish inhabiting polluted estuaries are highly exposed to severe stress characterized by an oxidant-antioxidant imbalance. The aim of the study was to explore the use of stress parameters such as adenosine triphosphate/adenosine diphosphate (ATP/ADP) ratio, mitochondrial membrane potential ({Delta}{psi}m) and total protein expression patterns as biomarkers against oxidant exposures in hepatocytes of Mugil cephalus living in either a contaminated (Test; Ennore) or uncontaminated (Control; Kovalam) estuary. Earlier, the pollutant stress impact was determined through light and electron microscopy studies. The ATP/ADP ratio was measured using high performance liquid chromatography; {Delta}{psi}m by fluorescent probe 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethyl benzimidazolcarbocyanine iodide (JC-1) dye and total protein expression patterns by protein profiling. The preponderance of stress impact was confirmed through microscopy studies that featured cytological alterations, disturbances in the surface morphology and in the cell organelles at the ultrastructural levels. Hepatocytes of test fish demonstrated a decrease in ATP and an increase in ADP and thereby alteration in ATP/ADP ratio (p < 0.05; 20.75%). A significant disturbance (p < 0.05; 26.57%) in {Delta}{psi}m with a ratio of J-aggregates/JC-1 monomer of 1 was observed for test fish hepatocytes compared to control group with a J-aggregates/JC-1 monomer ratio of 1.5. Quantitative assessment of protein expression levels also revealed enhanced induction of both low and high molecular weight proteins in test fish hepatocytes. The findings highlight the use of these parameters as the highly sensitive biomarkers in response to contaminant exposure compared to the routinely used antioxidant and oxidant stress parameters in biomonitoring programs. Among the measured parameters, the determination of {Delta}{psi}m may be suggested as a novel candidate as a biomarker because of its greater specificity and rapid quantitative risk assessment of pollutant exposures. - Highlights: {yields} We confirm the impact of environmental pollutant mediated oxidative stress on hepatocytes structures. {yields} Disturbance in bioenergetic status and {Delta}{psi}m, and induction of different kDa proteins were observed in stressed fish. {yields} Evaluation of stress parameters as biological markers is highly sensitive in comparison with routinely used biomarkers. {yields} {Delta}{psi}m determination provides more immediate, quantitative risk assessment of potentially deleterious environmental exposures. {yields} {Delta}{psi}m could function as a novel candidate as a biomarker and could be exploited among the others in biomonitoring programs.

Padmini, Ekambaram, E-mail: dstpadmini@rediffmail.com; Usha Rani, Munuswamy, E-mail: musharani.2007@rediffmail.com

2011-09-01

266

Mitochondrial membrane potential is a suitable candidate for assessing pollution toxicity in fish  

International Nuclear Information System (INIS)

Fish inhabiting polluted estuaries are highly exposed to severe stress characterized by an oxidant-antioxidant imbalance. The aim of the study was to explore the use of stress parameters such as adenosine triphosphate/adenosine diphosphate (ATP/ADP) ratio, mitochondrial membrane potential (??m) and total protein expression patterns as biomarkers against oxidant exposures in hepatocytes of Mugil cephalus living in either a contaminated (Test; Ennore) or uncontaminated (Control; Kovalam) estuary. Earlier, the pollutant stress impact was determined through light and electron microscopy studies. The ATP/ADP ratio was measured using high performance liquid chromatography; ??m by fluorescent probe 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethyl benzimidazolcarbocyanine iodide (JC-1) dye and total protein expression patterns by protein profiling. The preponderance of stress impact was confirmed through microscopy studies that featured cytological alterations, disturbances in the surface morphology and in the cell organelles at the ultrastructural levels. Hepatocytes of test fish demonstrated a decrease in ATP and an increase in ADP and thereby alteration in ATP/ADP ratio (p < 0.05; 20.75%). A significant disturbance (p < 0.05; 26.57%) in ??m with a ratio of J-aggregates/JC-1 monomer of 1 was observed for test fish hepatocytes compared to control group with a J-aggregates/JC-1 monomer ratio of 1.5. Quantitative assessment of protein expression levels also revealed enhanced induction of both low and high molecular weight proteins in test fish hepatocytes. The findings highlight the use of these parameters as the highly sensitive biomarkers in response to contaminant exposure compared to the routinely used antioxidant and oxidant stress parameters in biomonitoring programs. Among the measured parameters, the determination of ??m may be suggested as a novel candidate as a biomarker because of its greater specificity and rapid quantitative risk assessment of pollutant exposures. - Highlights: ? We confirm the impact of environmental pollutant mediated oxidative stress on hepatocytes structures. ? Disturbance in bioenergetic status and ??m, and induction of different kDa proteins were observed in stressed fish. ? Evaluation of stress parameters as biological markers is highly sensitive in comparison with routinely used biomarkers. ? ??m determination provides more immediate, quantitative risk assessment of potentially deleterious environmental exposures. ? ??m could function as a novel candidate as a biomarker and could be exploited among the others in biomonitoring programs.

267

Assessing estuarine environmental quality using fish-based indices: performance evaluation under climatic instability.  

Science.gov (United States)

The seasonal variation of five selected multimetric indices for the determination of the Ecological Quality Status (EQS) of transitional waters was evaluated, as well as the indices' responses to an extreme drought event that occurred in 2005. The database used regards the Mondego River estuary, which was sampled from June 2003 to August 2006 on a monthly basis. Among the selected indices (EBI-Deegan et al. [Deegan, L., Finn, J.T., Ayvazlan, S.G., Ryder-Kieffer, C.A., Buonaccoesi, J., 1997. Development and validation of an Estuarine Biotic Integrity Index. Estuaries 30(3), 601-617], EDI-Borja et al. [Borja, A., Franco, J., Valencia, V., Bald, J., Muxika, I., Belzunce, M.J., Solaun, O., 2004. Implementation of the European Water Framework Directive from the Basque Country (northern Spain): a methodological approach. Marine Pollution Bulletin 48(3-4), 209-218], EFCI-Harrison and Whitfield [Harrison, T.D., Whitfield, A.K., 2004. A multi-metric fish index to assess the environmental condition of estuaries. Journal of Fish Biology 65, 683-710], EBI-Breine et al. [Breine, J.J., Maes, J., Quataert, P., Van den Bergh, E., Simoens, I., Van Thuyne, G., Belpaire, C., 2007. A fish-based assessment tool for the ecological quality of the brackish Scheldt estuary in Flanders (Belgium). Hydrobiologia 575, 141-159] and TFCI - Coates et al. [Coates, S., Waugh, A., Anwar, A., Robson, M., 2007. Efficacy of a multi-metric fish index as an analysis tool for the transitional fish component of the Water Framework Directive. Marine Pollution Bulletin 55, 225-240]), the EBI by Breine et al. (2007) was the only that evidenced clear interannual and seasonal variations. The EQS by the several indices ranged from "Low" to "High", depending on the index considered, evidencing the high level of mismatch between indices. The results are discussed in the scope of the EU Water Framework Directive, regarding monitoring strategies, application of indices and EQS assessment. PMID:18790506

Martinho, F; Viegas, I; Dolbeth, M; Leitão, R; Cabral, H N; Pardal, M A

2008-11-01

268

The fish embryo toxicity test as an animal alternative method in hazard and risk assessment and scientific research  

Energy Technology Data Exchange (ETDEWEB)

Animal alternatives research has historically focused on human safety assessments and has only recently been extended to environmental testing. This is particularly for those assays that involve the use of fish. A number of alternatives are being pursued by the scientific community including the fish embryo toxicity (FET) test, a proposed replacement alternative to the acute fish test. Discussion of the FET methodology and its application in environmental assessments on a global level was needed. With this emerging issue in mind, the ILSI Health and Environmental Sciences Institute (HESI) and the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) held an International Workshop on the Application of the Fish Embryo Test as an Animal Alternative Method in Hazard and Risk Assessment and Scientific Research in March, 2008. The workshop included approximately 40 scientists and regulators representing government, industry, academia, and non-governmental organizations from North America, Europe, and Asia. The goal was to review the state of the science regarding the investigation of fish embryonic tests, pain and distress in fish, emerging approaches utilizing fish embryos, and the use of fish embryo toxicity test data in various types of environmental assessments (e.g., hazard, risk, effluent, and classification and labeling of chemicals). Some specific key outcomes included agreement that risk assessors need fish data for decision-making, that extending the FET to include eluethereombryos was desirable, that relevant endpoints are being used, and that additional endpoints could facilitate additional uses beyond acute toxicity testing. The FET was, however, not yet considered validated sensu OECD. An important action step will be to provide guidance on how all fish tests can be used to assess chemical hazard and to harmonize the diverse terminology used in test guidelines adopted over the past decades. Use of the FET in context of effluent assessments was considered and it is not known if fish embryos are sufficiently sensitive for consideration as a surrogate to the sub-chronic 7-day larval fish growth and survival test used in the United States, for example. Addressing these needs by via workshops, research, and additional data reviews were identified for future action by scientists and regulators.

Embry, Michelle R., E-mail: membry@ilsi.org [ILSI Health and Environmental Sciences Institute, 1156 15th Street, NW, Suite 200, Washington, DC 20005 (United States); Belanger, Scott E., E-mail: belanger.se@pg.com [Procter and Gamble, Central Product Safety, PO Box 538707, Miami Valley Innovation Center, Cincinnati, OH 45253-8707 (United States); Braunbeck, Thomas A., E-mail: braunbeck@zoo.uni-heidelberg.de [University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg D -69120 (Germany); Galay-Burgos, Malyka, E-mail: malyka.galay-burgos@ecetoc.org [European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC), 4 Avenue E. Van Nieuwenhuyse B-1160, Brussels (Belgium); Halder, Marlies, E-mail: marlies.halder@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, In-Vitro Methods Unit TP-580 Ispra 21027 (Italy); Hinton, David E., E-mail: dhinton@duke.edu [Duke University, Nicholas School of the Environment, PO Box 90328, Durham, NC 27708, Unites States (United States); Leonard, Marc A., E-mail: mleonard@rd.loreal.com [L' Oreal Recherche Avancee, Unite d' Ecotoxicologie, 1 av. E. Schueller, 93601 Aulnay sous bois (France); Lillicrap, Adam, E-mail: Adam.lillicrap@niva.no [AstraZeneca, Freshwater Quarry, Brixham TQ5 8BA (United Kingdom); Norberg-King, Teresa, E-mail: norberg-king.teresa@epa.gov [U.S. EPA, Mid-Continent Ecology Division, 6201 Congdon Boulevard, Duluth, MN 55804-1636 (United States); Whale, Graham, E-mail: graham.whale@shell.com [Shell Global Solutions, Analytical Technology, P.O. Box 1, Chester CH1 3SH (United Kingdom)

2010-04-15

269

The fish embryo toxicity test as an animal alternative method in hazard and risk assessment and scientific research  

International Nuclear Information System (INIS)

Animal alternatives research has historically focused on human safety assessments and has only recently been extended to environmental testing. This is particularly for those assays that involve the use of fish. A number of alternatives are being pursued by the scientific community including the fish embryo toxicity (FET) test, a proposed replacement alternative to the acute fish test. Discussion of the FET methodology and its application in environmental assessments on a global level was needed. With this emerging issue in mind, the ILSI Health and Environmental Sciences Institute (HESI) and the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) held an International Workshop on the Application of the Fish Embryo Test as an Animal Alternative Method in Hazard and Risk Assessment and Scientific Research in March, 2008. The workshop included approximately 40 scientists and regulators representing government, industry, academia, and non-governmental organizations from North America, Europe, and Asia. The goal was to review the state of the science regarding the investigation of fish embryonic tests, pain and distress in fish, emerging approaches utilizing fish embryos, and the use of fish embryo toxicity test data in various types of environmental assessments (e.g., hazard, risk, effluent, and classification and labeling of chemicals). Some specific key outcomes included agreement that risk assessors need fish data for decision-making, that extendingh data for decision-making, that extending the FET to include eluethereombryos was desirable, that relevant endpoints are being used, and that additional endpoints could facilitate additional uses beyond acute toxicity testing. The FET was, however, not yet considered validated sensu OECD. An important action step will be to provide guidance on how all fish tests can be used to assess chemical hazard and to harmonize the diverse terminology used in test guidelines adopted over the past decades. Use of the FET in context of effluent assessments was considered and it is not known if fish embryos are sufficiently sensitive for consideration as a surrogate to the sub-chronic 7-day larval fish growth and survival test used in the United States, for example. Addressing these needs by via workshops, research, and additional data reviews were identified for future action by scientists and regulators.

270

Assessment of Present Anadromous Fish Production Facilities in the Columbia River Basin, Washington Department of Fish Hatcheries, Final Report.  

Energy Technology Data Exchange (ETDEWEB)

The goal of this report is to document current production practices for hatcheries which rear anadromous fish in the Columbia River Basin and to identify those facilities where production can be increased. A total of 85 hatchery and satellite facilities operated by the Idaho Department of Fish and Game, Oregon Department of Fish and Game, US Fish and Wildlife Service, Washington Department of Wildlife, and Washington Department of Fisheries were evaluated. The years 1985 to 1987 were used in this evaluation. During those years, releases averaged 143,306,596 smolts weighing 7,693,589 pounds. A total of 48 hatchery or satellite facilities were identified as having expansion capability. They were estimated to have the potential for increasing production by an 84,448,000 smolts weighing 4,853,306 pounds. 2 refs., 25 figs.

Delarm, Michael R.; Smith, Robert Z.

1990-07-01

271

Designing and validating the methodology for the Internet assessment of fish consumption at a university setting  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Assessing fish consumption is complex and involves several factors; however, the use of questionnaires in surveys and the use of the Internet as tool to collect data have been considered promising approaches. Therefore, the objective of this research was to design a data collection technique using a [...] questionnaire to assess fish consumption by making it available on a specific home page on the Internet. A bibliographical survey or review was carried out to identify the features of the instrument, and therefore pre-tests were conducted with previous instruments, followed by the Focus Group technique. Specialists then performed an analysis and conducted an online pre-test. Multivariate data analysis was applied using the SmartPLS software. The results indicate that 1.966 participants belonging to the University of São Paulo (USP) community participated in the test, and after the exclusion of some variables, a statistically significant results were obtained. The final constructs comprised consumption, quality, and general characteristics. The instrument consisted of behavioral statements in a 5-point Likert scale and multiple-choice questions. The Cronbach's alpha reliability coefficient was 0.66 for general characteristics, 0.98 for quality, and 0.91 for consumption, which indicate good reliability of the instrument. In conclusion, the results proved that the Internet assessment is efficient. The instrument of analysis allowed us to better understand the process of buying and consuming fish in the country, and it can be used as base for further research.

Erika da Silva, Maciel; Julia Santos, Vasconcelos; Luciana Kimie Savay da, Silva; Jaqueline Girnos, Sonati; Juliana, Galvão; Dirceu da, Silva; Marília, Oetterer.

2014-06-01

272

Designing and validating the methodology for the Internet assessment of fish consumption at a university setting  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Assessing fish consumption is complex and involves several factors; however, the use of questionnaires in surveys and the use of the Internet as tool to collect data have been considered promising approaches. Therefore, the objective of this research was to design a data collection technique using a [...] questionnaire to assess fish consumption by making it available on a specific home page on the Internet. A bibliographical survey or review was carried out to identify the features of the instrument, and therefore pre-tests were conducted with previous instruments, followed by the Focus Group technique. Specialists then performed an analysis and conducted an online pre-test. Multivariate data analysis was applied using the SmartPLS software. The results indicate that 1.966 participants belonging to the University of São Paulo (USP) community participated in the test, and after the exclusion of some variables, a statistically significant results were obtained. The final constructs comprised consumption, quality, and general characteristics. The instrument consisted of behavioral statements in a 5-point Likert scale and multiple-choice questions. The Cronbach's alpha reliability coefficient was 0.66 for general characteristics, 0.98 for quality, and 0.91 for consumption, which indicate good reliability of the instrument. In conclusion, the results proved that the Internet assessment is efficient. The instrument of analysis allowed us to better understand the process of buying and consuming fish in the country, and it can be used as base for further research.

Erika da Silva, Maciel; Julia Santos, Vasconcelos; Luciana Kimie Savay da, Silva; Jaqueline Girnos, Sonati; Juliana, Galvão; Dirceu da, Silva; Marília, Oetterer.

273

Assessment of fish health effects resulting from exposure to oil sands wastewater  

International Nuclear Information System (INIS)

The objective of this study was to determine if oil sands wastewater had an effect on the general health and condition of hatchery raised rainbow trout (200 to 400 g). Effects were assessed based on a battery of physiological and biochemical indices and the physical condition of the fish. The trout were exposed to tailings water in the field and in a flow through system under laboratory conditions. The field tests were conducted in 1992 and 1993 in experimental ponds at Syncrude which contained fine tails covered with surface water, fine tails covered with tailings water, and a surface water control pond. The laboratory treatments included Mildred Lake tailings water, dyke drainage water, fractionated tailings pond water (acid fraction containing naphthenic acids), sodium naphthenate, recycle water from Suncor's tailings pond, and a laboratory control. All body condition factors and blood parameters were normal in the field and laboratory exposed fish and there were no apparent differences between the fish exposed to the tailings water and controls

274

Growth history and intrinsic factors influence risk assessment at a critical life transition for a fish  

Science.gov (United States)

Making the appropriate decision in the face of predation risk dictates the fate of prey, and predation risk is highest at life history boundaries such as settlement. At the end of the larval phase, most coral reef fishes enter patches of reef containing novel predators. Since vision is often obscured in the complex surroundings, chemical information released from damaged conspecific is used to forewarn prey of an active predator. However, larvae enter the reef environment with their own feeding and growth histories, which will influence their motivation to feed and take risks. The present study explored the link between recent growth, feeding history, current performance and behavioural risk taking in newly settling stages of a coral reef damselfish ( Pomacentrus amboinensis). Older and larger juveniles in good body condition had a stronger response to chemical alarm cues of injured conspecifics; these fish spent a longer time in shelter and displayed a more dramatic decrease in foraging behaviour than fish in lower body condition. Feeding experiments supported these findings and emphasized the importance of body condition in affecting risk assessment. Evidently, larval growth history and body condition influences the likelihood of taking risks under the threat of predation immediately after settlement, thereby affecting the probability of survival in P. amboinensis.

Lönnstedt, O. M.; McCormick, M. I.

2011-09-01

275

Comparative toxicology for risk assessment of marine fishes and crustaceans. [Cyprinodon variegatus  

Energy Technology Data Exchange (ETDEWEB)

The goal of this study was to collect data on the effects of chemicals on marine fishes and crustaceans and to evaluate the predictive power of the data for assessing risks to marine resources. The data sets consisted of acute median lethal concentrations (LC{sub 50s}) and chronic maximum acceptable toxicant concentrations (MATCs). They were analyzed with regression models and simple comparisons. The conclusions include the following: (1) the variability found in the marine data was comparable to that found in freshwater data; (2) the standard marine test fish Cyprinodon variegatus appears to be representative of marine fishes; (3) the responses of marine crustaceans are so highly diverse that the concept of a representative crustacean is questionable; (4) mysid and penaeid shrimp appear to be particularly sensitive to toxic chemicals. These conclusions are subject to the constraints of the existing limited data base and should be confirmed by a systematic study of the relative sensitivity of marine organisms to chemicals with diverse modes of action.

Suter, G.W. II; Rosen, A.E. (Oak Ridge National Lab., TN (USA))

1988-05-01

276

First record of Chilodonella hexasticha (Ciliophora: Chilodonellidae) in Brazilian cultured fish: a morphological and pathological assessment.  

Science.gov (United States)

Chilodonelids are small ciliated protozoans found worldwide and can be dangerous in culture conditions. This study presents morphometric data on the ciliate Chilodonella that is found in cultured Nile tilapia (Oreochromis niloticus), native bait fish tuvira (Gymnotus aff. inaequilabiatus) and native pacu (Piaractus mesopotamicus) and includes a histopathological assessment of the changes that occur in the pacu. For parasitic diagnosis, skin and gill samples were scraped onto slides, dried at room temperature, stained with Giemsa or impregnated with silver nitrate, and the measurements were obtained from photomicrographs. In the diseased pacu, the first gill arch was collected and fixed in a 10% buffered formalin solution for histopathological analysis. Parasite specimens from the different collection sites were identified morphologically as C. hexasticha Kiernik (1909). Diseased fish exhibited depigmentation, skin ulceration, scale loss, excessive mucus production and gill lesions. Histopathological analysis of pacu gills displayed epithelial proliferation with mononuclear inflammatory infiltrate, hemorrhages, and scattering necrosis. In Brazilian-farmed fish this is the first record of C. hexasticha, which has great pathogenic potential in cultured freshwater species. In addition, two new hosts are presented. PMID:22902259

Pádua, S B; Martins, M L; Carrijo-Mauad, J R; Ishikawa, M M; Jerônimo, G T; Dias-Neto, J; Pilarski, F

2013-01-16

277

Genetic Variability in Cultured Stocks of Scleropages formosus in Mainland China Revealed by Microsatellite Markers  

Directory of Open Access Journals (Sweden)

Full Text Available The Asian arowana, Scleropages formosus (Osteoglossidae is one of the most valuable species of the ornamental fish which has an important role on academic study and economic development. The present study assessed the genetic variation of three S. formosus stocks cultured in ponds using 39 polymorphic microsatellite primer combinations. The results showed the middle level of genetic diversity among all three stocks. The average values of observed Heterozygosity (Ho expected Heterozygosity (He for the red stocks are the highest which were 0.509 and 0.552, respectively. Genetic diversity of the green stocks was higher than the golden group. The inbreeding coeffcients within the subpopulation (Fis and the differentiation index of population (Fst analyses showed low genetic differentiation among three cultured stocks. The cluster analysis based on Neis standard genetic distance showed that the golden and the green stocks clustered together and the red stock was in another clade. These results would have important implications for future breeding programs, conservation and production, suitable management guideline projects for S. formosus in mainland China.

J.R. Luo

2011-01-01

278

Do North Sea cod (Gadus morhua) fisheries maintain high catch rates at low stock size?  

DEFF Research Database (Denmark)

This study presents all investigation of the relationship between stock size of North Sea cod (Gadus morhua) and catch rates in seven commercial fishing fleets. The shape of the relationship was estimated using a model allowing both density-dependent changes in catchability and bias in the assessment biomass estimates. Catchability in fisheries targeting a mixed species composition either remained constant or decreased with decreasing stock size, whereas catchability in targeted cod fisheries increased with decreasing stock size. However, even ill the cases where catchability increased, the change was insufficient to compensate for the decrease in stock size, and catch rates of all fleets decreased. Two factors that could lead to nonconstant catchability were investigated: (i) the presence of decoupling between stock size and density ill high-density areas and (ii) the presence of concurrent shifts in the spatial distribution of the cod stock and the cod fishery. No evidence of the former was found but there was a northern shift in the spatial distribution of both effort and the cod stock.

Rindorf, Anna; Andersen, Bo SØlgaard

2008-01-01

279

About stock markets predictability  

Directory of Open Access Journals (Sweden)

Full Text Available We argue that the financial markets have a predetermined outcome. They behave deterministically but appear to follow random patterns. Stock prices have nothing to do with future expectations; they are a reflection of previous convictions coming from the confident investors. A financial crisis is the result of the lack of confidence that characterizes a market moments before the crisis. Stocks returns are perfectly correlated to each other and it is possible to obtain high gains consistently. Finally we provide a different way of assessing risk and suggest a method to sense future performances.

Hicham Benjelloun

2011-01-01

280

Screening level fish community risk assessment of chemical warfare agents in the Baltic Sea.  

Science.gov (United States)

Chemical warfare agents (CWAs) have been disposed of in various fashions over the past decades. Significant amounts (approximately 11,000 tonnes) have been dumped in the Baltic Sea east of the island Bornholm following the disarmament of Germany after World War II, causing concerns over potential environmental risks. Absence of risk based on assumptions of extremely low solubility of CWAs cannot alone dismiss these concerns. Existing and modelled fate and effects data were used in the analysis to assess the fish community risk level. The most realistic and also conservative assessment result is the scenario describing 70 m water depth for the most realistic dump-site area with a focus on chronic toxicity, at 0-20 cm above the sediment, yielding a total mixture toxic unit (TU) of 0.62. Triphenylarsine is the CWA with the highest realistic risk profile at 0.2 TU for the fish community followed by Adamsite (0.17), Clark I (0.086) and Yperite (0.083) TU. Adamsite is more persistent and constitutes a potential risk for a longer period than triphenylarsine. The seawater volume potentially at risk is <4 m above sediment and <58 km down current of dump sites. Further risk assessment of dumped CWAs in the Baltic Sea is warranted. PMID:18079057

Sanderson, Hans; Fauser, Patrik; Thomsen, Marianne; Sørensen, Peter B

2008-06-15

 
 
 
 
281

Living Stock Collections (LSC)  

Science.gov (United States)

... Program Title: Living Stock Collections (LSC) Synopsis of Program: The Living Stock Collections ... of outstanding collections of living organisms through the Living Stock Collections (LSC) Program ...

282

Use of In Vitro Absorption, Distribution, Metabolism, and Excretion (ADME) Data in Bioaccumulation Assessments for Fish  

Energy Technology Data Exchange (ETDEWEB)

A scientific workshop was held in 2006 to discuss the use of in vitro Absorption, Distribution, Metabolism, and Excretion (ADME) data in chemical bioaccumulation assessments for fish. Computer-based (in silico) modeling tools are widely used to estimate chemical bioaccumulation. These in silico methods have inherent limitations that result in inaccurate estimates for many compounds. Based on a review of the science workshop participants concluded that two factors, absorption and metabolism, represent the greatest sources of uncertainty in current bioaccumulation models. Both factors can be investigated experimentally using in vitro test systems.

Nichols, John W.; Erhardt, Susan; Dyer, Scott; James, Margaret O.; Moore, Margo; Plotzke, Kathleen; Segner, Helmut; Schultz, Irvin R.; Thomas, Karluss; Vasiluk, Luba; Weisbrod, Anne V.

2007-11-01

283

"We Like to Listen to Stories about Fish": Integrating Indigenous Ecological and Scientific Knowledge to Inform Environmental Flow Assessments  

Directory of Open Access Journals (Sweden)

Full Text Available Studies that apply indigenous ecological knowledge to contemporary resource management problems are increasing globally; however, few of these studies have contributed to environmental water management. We interviewed three indigenous landowning groups in a tropical Australian catchment subject to increasing water resource development pressure and trialed tools to integrate indigenous and scientific knowledge of the biology and ecology of freshwater fish to assess their water requirements. The differences, similarities, and complementarities between the knowledge of fish held by indigenous people and scientists are discussed in the context of the changing socioeconomic circumstances experienced by indigenous communities of north Australia. In addition to eliciting indigenous knowledge that confirmed field fish survey results, the approach generated knowledge that was new to both science and indigenous participants, respectively. Indigenous knowledge influenced (1 the conceptual models developed by scientists to understand the flow ecology and (2 the structure of risk assessment tools designed to understand the vulnerability of particular fish to low-flow scenarios.

Sue E. Jackson

2014-03-01

284

Health risk assessment from mercury levels in bycatch fish species from the coasts of Guerrero, Mexico (Eastern Pacific).  

Science.gov (United States)

With the aim of determining Hg distribution in muscle and liver of bycatch fish from Guerrero state in the Eastern Pacific Ocean and assess the potential risk to consumer, Hg was quantified in 14 species of bycatch fish. For the majority of fish the order of Hg levels was liver > muscle. The highest concentration corresponded to the liver of Isopisthus remifer (2.05 µg g(-1)) and the lowest (0.02 µg g(-1)) was detected in muscle of Prionotus sp. The highest hazard quotient (0.75) was found in the Mexican milkfish Micropogonias ectenes; considering all the individuals, mean hazard quotient was 0.336. PMID:24902649

Spanopoulos-Zarco, P; Ruelas-Inzunza, J; Meza-Montenegro, M; Osuna-Sánchez, K; Amezcua-Martínez, F

2014-09-01

285

Tracking stock  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tracking stock so posebna vrsta delnic, ki so razvite oziroma razširjene predvsem v Združenih državah Amerike, pri nas ta vrsta delnic ni poznana. Delnice predstavljajo dolo?en obrat družbe ali h?erinsko družbo. Te vrste delnic omogo?ajo upravi, da obdrži nadzor nad posameznim obratom ali h?erinsko družbo. ?e družba izda tracking stock, lahko odlo?a med prodajo na trgu (to je, prek za?etne javne ponudba ali IPO) ali za distribucijo novih delnic obstoje?im delni?arjem. Im...

S?unko, Petra

2009-01-01

286

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

Science.gov (United States)

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. PMID:19932535

Muñoz, Ivan; Martínez Bueno, María J; Agüera, Ana; Fernández-Alba, Amadeo R

2010-05-01

287

Immunotoxic effects of environmental toxicants in fish - how to assess them?  

Science.gov (United States)

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens. PMID:22828877

Segner, Helmut; Wenger, Michael; Möller, Anja Maria; Köllner, Bernd; Casanova-Nakayama, Ayako

2011-08-01

288

Ecological risk assessment and management of invasive freshwater fish species from aquarium and ornamental trades in Hong Kong  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Since globalization have promoted the ornamental trade and accelerated the movement of freshwater fishes around the world, non-native species pose a high potential to be released into local freshwater habitats, and to spread and establish as invasive and nuisance species with adverse ecological, economic and social impacts. This study aimed to investigate the potential of the ornamental freshwater fish trade as an invasion pathway in Hong Kong, assess the ecological risk of common aquarium fr...

Ho, Chi-fai; ???

2013-01-01

289

Using condition factor and blood variable biomarkers in fish to assess water quality.  

Science.gov (United States)

The condition factor and blood variables, including erythrocyte lipid peroxidation (LPO) and the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in two ecologically distinct fish species (Astyanax fasciatus and Pimelodus maculatus) were evaluated at five sites in the Furnas Hydroelectric Power Station reservoir (Brazil) to assess water quality. Aldrin/dieldrin, endosulfan, heptachlor epoxide, and metolachlor were detected at different concentrations in four of the sites. Condition factor was not directly affected by such contaminants. A negative correlation between hematocrit and heptachlor was detected in P. maculatus. Positive correlations between red blood cells and heptachlor as well as an interactive effect of metolachlor and aldrin/dieldrin were detected in A. fasciatus. The erythrocytes of both species collected from the contaminated sites showed high levels of LPO, an increase in SOD and GPx activities and a decrease in CAT activity. Although the leukocyte number and the differential percentage of leukocytes varied among the sites, the hematological variables, the LPO levels, and the antioxidant enzyme activities could be used to assess water quality, regardless of the differences in the responses of the fish species. PMID:21152972

Sadauskas-Henrique, Helen; Sakuragui, Marise M; Paulino, Marcelo G; Fernandes, Marisa N

2011-10-01

290

The Applicability of Oxidative Stress Biomarkers in Assessing Chromium Induced Toxicity in the Fish Labeo rohita  

Science.gov (United States)

The evaluation of metal's toxicity in freshwater is one of the imperative areas of research and there is an emergent concern on the development of techniques for detecting toxic effects in aquatic animals. Oxidative stress biomarkers are very useful in assessing the health of aquatic life and more in depth studies are necessary to establish an exact cause effect relationship. Therefore, to study the effectiveness of this approach, a laboratory study was conducted in the fish Labeo rohita as a function of hexavalent chromium and the toxicity indices using a battery of oxidative stress biomarkers such as catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) in the liver, muscle, gills, and brain have been studied along with biometric parameters, behavioral changes, and Cr bioaccumulation. A significant increased HSI was observed in contrast to CF which reduced significantly. SOD, CAT, and GR activity increased significantly in all the tissues of treated fishes. The bioaccumulation of Cr was highest in liver followed by gills, muscle, and brain. This study highlights the significance of using a set of integrated biomarker and advocate to include these parameters in National Water Quality Monitoring Program in areas potentially polluted with metals to assess the health of the ecosystem.

Khare, Ankur; Dange, Swati

2014-01-01

291

Dose assessment of past accidental or chronic exposure using FISH chromosome painting  

International Nuclear Information System (INIS)

In order to evaluate the practicality of FISH (fluorescence in situ hybridisation) chromosome painting for retrospective biodosimetry, more information on the stability of translocations with time and the control level of translocations is needed. The temporal behaviour of translocation frequency in four accidentally exposed subjects showed that translocations remained relatively stable throughout the first post-accidental years. A decline in translocation yields was, however, observed in one subject exposed to both high dose and partial body irradiation that lead to severe aplasia. This finding implies that FISH biodosimetry may not be informative in cases where the dose has not been uniformly distributed. In our studies, significant age dependence and wide translocation range has been observed. In dose assessment of low dose exposure to a large number of people the age effect has been accounted for by comparing the results with a matched control group. Our data support the use of translocations for retrospective dosimetry for moderately high doses of the order of 1 Gy acute exposure with uniform whole-body exposures. In low dose chronic exposures, reliable assessment of past exposures can be achieved on group level. (author)

292

The applicability of oxidative stress biomarkers in assessing chromium induced toxicity in the fish Labeo rohita.  

Science.gov (United States)

The evaluation of metal's toxicity in freshwater is one of the imperative areas of research and there is an emergent concern on the development of techniques for detecting toxic effects in aquatic animals. Oxidative stress biomarkers are very useful in assessing the health of aquatic life and more in depth studies are necessary to establish an exact cause effect relationship. Therefore, to study the effectiveness of this approach, a laboratory study was conducted in the fish Labeo rohita as a function of hexavalent chromium and the toxicity indices using a battery of oxidative stress biomarkers such as catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) in the liver, muscle, gills, and brain have been studied along with biometric parameters, behavioral changes, and Cr bioaccumulation. A significant increased HSI was observed in contrast to CF which reduced significantly. SOD, CAT, and GR activity increased significantly in all the tissues of treated fishes. The bioaccumulation of Cr was highest in liver followed by gills, muscle, and brain. This study highlights the significance of using a set of integrated biomarker and advocate to include these parameters in National Water Quality Monitoring Program in areas potentially polluted with metals to assess the health of the ecosystem. PMID:25302308

Kumari, Kanchan; Khare, Ankur; Dange, Swati

2014-01-01

293

Biomarkers as tools in quality assessment of fish contaminated with trace metals  

Directory of Open Access Journals (Sweden)

Full Text Available Trace metals that present toxicity to vertebrates are cause of concern in environmental monitoring programs due to impact caused by anthropogenic activity. The distribution of these elements is found in different settings: water, sediment and biota. Metals such as Pb, Cd, Hg, As and Cr are related to significant environmental damage, which can contaminate man, primarily by fish consumption. Some biomarkers can be applied via an impact approach, and risk assessment for populations of species susceptible to exposure and toxic effects of trace metals. Acetylcholinesterase, metallothionein, delta-aminolevulinic acid dehydratase, and the micronucleus test can be used together as biomarkers for aquatic organisms that are exposed or affected by toxic metals. The CONAMA Resolution 357/2005 of the Brazilian Ministry of the Environment and the Ordinance 2914/2011 from  Ministry of Health set limits for these toxic metals in surface and drinking water respectively. However, it still does not require the determination of chemical species, relative to the bioavailability produced in different arrays, neither to sublethal effects, evaluated by biomarkers, of these metals on aquatic organisms. The purpose of this review is to present the biomarkers (genetic and biochemical as tools to aid assessment of the quality of fish.

Rodolfo dos Santos Coutinho Coimbra

2013-09-01

294

Proxies for estimation of relative fishing mortality when biomass is unknown  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Marine Strategy Framework Directive proposes two indicators for assessing the level of pressure of fishing activities on the target species. The primary indicator is the fishing mortality (F) relative to the one (Fmsy) that will eventually lead to the maximum sustainable yield. The secondary indicator is the catch/biomass ratio relative to a catch/biomass proxy for Fmsy. Both indicators and their reference points need biomass of the target stock to be known. Biomass is, however, unknown f...

Froese, Rainer; Sampang, A.

2012-01-01

295

75 FR 30779 - Fisheries of the Exclusive Economic Zone off Alaska; Stock Assessment of Eastern Bering Sea...  

Science.gov (United States)

...Management Council (NPFMC) Plan Team, and the NPFMC Scientific and...understanding the population dynamics and stock status of Eastern...to the September NPFMC Plan Team meetings and will consist of...the September 2010 NPFMC Plan Team meeting, which will be...

2010-06-02

296

A Multiple Watershed Approach to Assessing the Effects of Habitat Restoration Actions on Anadromous and Resident Fish Populations, Technical Report 2003-2004.  

Energy Technology Data Exchange (ETDEWEB)

Habitat protection and restoration is a cornerstone of current strategies to restore ecosystems, recover endangered fish species, and rebuild fish stocks within the Columbia River Basin. Strategies featuring habitat restoration include the 2000 Biological Opinion on operation of the Federal Columbia River Power System (FCRPS BiOp) developed by the National Marine Fisheries Service (NMFS), the 2000 Biological Opinion on Bull Trout developed by the US Fish and Wildlife Service (USFWS), and Sub-Basin Plans developed under the Fish and Wildlife Program of the Northwest Power and Conservation Council (NWPCC). There is however little quantitative information about the effectiveness of different habitat restoration techniques. Such information is crucial for helping scientists and program managers allocate limited funds towards the greatest benefits for fish populations. Therefore, it is critical to systematically test the hypotheses underlying habitat restoration actions for both anadromous and resident fish populations. This pilot project was developed through a proposal to the Innovative Projects fund of the NWPCC (ESSA 2002). It was funded by the Bonneville Power Administration (BPA) following reviews by the Independent Scientific Review Panel (ISRP 2002), the Columbia Basin Fish and Wildlife Authority (CBFWA 2002), the NWPCC and BPA. The study was designed to respond directly to the above described needs for information on the effectiveness of habitat restoration actions, including legal measures specified in the 2000 FCRPS BiOp (RPA 183, pg. 9-133, NMFS 2000). Due to the urgency of addressing these measures, the timeline of the project was accelerated from a duration of 18 months to 14 months. The purpose of this pilot project was to explore methods for evaluating past habitat restoration actions and their effects on fish populations. By doing so, the project will provide a foundation of retrospective analyses, on which to build prospective, multi-watershed designs for future habitat restoration actions. Such designs are being developed concurrently with this project by several other groups in the Columbia Basin (RME Workgroup 2003, NMFS 2003, Hillman and Paulsen 2002, Hillman 2003). By addressing questions about habitat restoration and monitoring (in coordination with other related efforts), we hope that this project will catalyze a shift in the Basin's paradigm of habitat restoration, moving from implementation of individual watershed projects towards rigorously designed and monitored, multiwatershed, adaptive management experiments. The project involved three phases of work, which were closely integrated with various related and ongoing efforts in the region: (1) Scoping - We met with a Core Group of habitat experts and managers to scope out a set of testable habitat restoration hypotheses, identify candidate watersheds and recommend participants for a data evaluation workshop. (2) Data Assembly - We contacted over 80 scientists and managers to help evaluate the suitability of each candidate watershed's historical data for assessing the effectiveness of past restoration actions. We eventually settled on the Yakima, Wenatchee, Clearwater, and Salmon subbasins, and began gathering relevant data for these watersheds at a workshop with habitat experts and managers. Data assembly continued for several months after the workshop. (3) Data Analysis and Synthesis - We explored statistical approaches towards retrospectively analyzing the effects of restoration 'treatments' at nested spatial scales across multiple watersheds (Chapters 2-5 of this report). These analyses provided a foundation for identifying existing constraints to testing restoration hypotheses, and opportunities to overcome these constraints through improved experimental designs, monitoring protocols and project selection strategies (Chapters 6 and 7 of this report). Finally, we developed a set of recommendations to improve the design, implementation, and monitoring of prospective habitat restoration programs in the Columbia River Basin (Chap

Marmorek, David

2004-03-01

297

Heavy metals and arsenic concentrations in ten fish species from the Šalek lakes (Slovenia): assessment of potential human health risk due to fish consumption.  

Science.gov (United States)

The study, which measured the concentrations of Hg, Pb, Cd, Zn and As in various fish tissues (muscle, gill and liver) of 10 fish species (Abramis brama danubii, Alburnus alburnus alburnus, Barbus meridionalis petenyi, Carassius auratius gibelio, Cyprinus carpio, Lepomis gibossus, Leuciscius cephalus cephalus, Perca fluviatilis fluviatilis, Rutilus rutilus, Scardinus erythrophtlalmus erythrophtlalmus) collected in the Šalek lakes, is the first survey regarding metal concentrations in fish species with samples originating from Slovene lakes, while only a limited number of such studies have been carried out in southeastern Europe. Since these lakes are situated in the close vicinity of the largest Slovene thermal power plant, the study provides an insight into the potential impact of increased levels of metals in the environment as well as an estimate of the contamination of fish tissues with metals. Furthermore, it was possible to compare the results obtained with those from other studies regarding metal levels in freshwater fish species. The mean metal concentrations of different tissues irrespective of species varied in the following ranges: Zn 4.31-199 mg/kg ww, Pb 0.01-0.48 mg/kg ww, As 0.02-0.44 mg/kg ww, Hg <0.01-0.31 mg/kg ww, Cd < 0.01-0.19 mg/kg ww. In general, higher contents of Hg were found in muscles and livers than in gills and higher contents of As in gills and livers than in muscles, respectively. The accumulation of Pb and Zn was most pronounced in gills. The result obtained regarding metal concentrations in fish revealed that the ecosystems of the Šalek lakes are not polluted with Hg and Pb, slightly loaded with As and Cd and moderately polluted with Zn. In addition, the potential human health risk due to fish consumption was assessed. This showed that the estimated weekly intakes for all metals were far below provisional permissible tolerable weekly intakes determined by WHO/FAO. The consumption of fish from the Šalek lakes, therefore, does not pose a risk to human health. PMID:21713497

Al Sayegh Petkovšek, Samar; Mazej Grudnik, Zdenka; Pokorny, Boštjan

2012-05-01

298

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

International Nuclear Information System (INIS)

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.

299

The fish community of a moderately exposed beach on the southwestern Cape coast of South Africa and an assessment of this habitat as a nursery for juvenile fish  

Science.gov (United States)

The ichthyofauna of a moderately exposed surf-zone habitat on the southwestern Cape coast of South Africa was sampled by seine netting monthly for 13 months. Twenty species of fish, 40 306 individuals weighing a total of 211 kg were captured. The number of species and standing crop varied seasonally with higher values occurring during the summer (January-March). The average summer standing stock of 38·6 g m -2 was considerably higher than any previously recorded from a surf-zone habitat and the annual average (10·1 g m -2 was comparable with that in estuaries. Eighteen of the species sampled occurred almost exclusively as juveniles and only two as adults. Four species were present throughout the year, 11 of them seasonally and the remaining five sporadically. Small juveniles (20-35 mm) typically appeared in the surf-zone 2-4 months after they were spawned. These 0+ juveniles remained there for between three months and one year depending on species, before vacating the surf-zone for their adult habitats. A comparison of the abundance of juveniles in the surf-zone with other inshore marine habitats suggested that five species ( Amblyrhynchotes honckenii, Cheilodonichthys capensis, Diplodus sargus, Lithognathus mormyrus and Pomadasys olivaceum) may be entirely, and three species ( Lichia amia, Liza richardsoni and Rhabdosargus globiceps) largely, dependent on the surf-zone as a nursery area. It was concluded that the surf-zone of sandy beaches may be as important as estuaries as a nursery habitat for juvenile fish.

Bennett, B. A.

1989-03-01

300

Determination of toxic elements (mercury, cadmium, lead, tin and arsenic) in fish and shellfish samples. Risk assessment for the consumers.  

Science.gov (United States)

Although fish intake has potential health benefits, the presence of metal contamination in seafood has raised public health concerns. In this study, levels of mercury, cadmium, lead, tin and arsenic have been determined in fresh, canned and frozen fish and shellfish products and compared with the maximum levels currently in force. In a further step, potential human health risks for the consumers were assessed. A total of 485 samples of the 43 most frequently consumed fish and shellfish species in Andalusia (Southern Spain) were analyzed for their toxic elements content. High mercury concentrations were found in some predatory species (blue shark, cat shark, swordfish and tuna), although they were below the regulatory maximum levels. In the case of cadmium, bivalve mollusks such as canned clams and mussels presented higher concentrations than fish, but almost none of the samples analyzed exceeded the maximum levels. Lead concentrations were almost negligible with the exception of frozen common sole, which showed median levels above the legal limit. Tin levels in canned products were far below the maximum regulatory limit, indicating that no significant tin was transferred from the can. Arsenic concentrations were higher in crustaceans such as fresh and frozen shrimps. The risk assessment performed indicated that fish and shellfish products were safe for the average consumer, although a potential risk cannot be dismissed for regular or excessive consumers of particular fish species, such as tuna, swordfish, blue shark and cat shark (for mercury) and common sole (for lead). PMID:23792415

Olmedo, P; Pla, A; Hernández, A F; Barbier, F; Ayouni, L; Gil, F

2013-09-01

 
 
 
 
301

Assessment of Hydroponically Grown Macrophytes for Their Suitability as Fish Feed  

Directory of Open Access Journals (Sweden)

Full Text Available Water hyacinth, water lettuce and parrot's feather plants were examined for their ability to remove nutrients from aquaculture wastewater at two retention times. During the experiment, the aquatic plants grew rapidly in the hydroponics system and appeared healthy with green color. At hydraulic retention times (HRTs of 6 and 12 days, the average water hyacinth, water lettuce and parrot's feather yields were 83, 51 and 51 g (dm m-2 and 49, 29 and 22 g (dm m-2, respectively. The aquatic plants were able to significantly reduce the pollution load of the aquaculture wastewater. The TS, COD, NH4+-N, NO2--N, NO3--N and PO43--P reductions ranged from 21.4 to 48.0%, from 71.1 to 89.5%, from 55.9 to 76.0%, from 49.6 to 90.6%, from 34.5 to 54.4% and from 64.5 to 76.8%, respectively. Generally, the reductions increased with longer retention times and were highest in compartments containing water hyacinth followed by compartments containing water lettuce and parrot's feather. The nutritive value of the three wastewater grown plants was assessed to determine the suitability of using the plants as a component in fish feed. The three wastewater grown plants did not contain sufficient amounts of protein and fat to meet the dietary requirements of fish and shellfish. They also contained high concentrations of K, Cu, Fe, Mn, Se and Zn, which can lead to reduced feed intake, weight gain and growth rates in fish and shellfish.

A. M. Snow

2008-01-01

302

Assessment against the principles and criteria of the MSC for sustainable fishing, Southern Brittany's purse seine Sardine fishery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report presents the result of the South-Brittany Purse-seine sardine Fishery assessment against Marine Steawardship Council Principles and Criteria. The client of this assessment is the "Association des Bolincheurs de Bretagne". The fishery covered by the assessment is managed by the French Committees for fisheries and marine farms (CRPMEM) supervised by the Producers Organization. The target species, Common sardine (Sardina pilchardus) is fished in the 12 nautil mile area in the ICESare...

Des Clers, Sophie; Gascuel, Didier; Lagadec, Xavie?re; Lesueur, Marie; Le Pape, Olivier

2010-01-01

303

Residual levels of DDTs and PAHs in freshwater and marine fish from Hong Kong markets and their health risk assessment.  

Science.gov (United States)

Axial and ventral muscle from 10 each species of freshwater and marine fish purchased from markets in Hong Kong were analyzed for dichlorodiphenyltrichloroethane (total DDTs including DDE, DDD and DDT) and polycyclic aromatic hydrocarbons (PAHs). Among the 10 freshwater fish species, rice field eel (Monopterus albus) showed significantly higher levels of DDTs in both ventral (125 ng/g wet wt) and axial muscle (127 ng/g wet wt) than the other species. The highest concentration of PAHs was detected in catfish (Clarias fuscus), with 24.8 ng/g in ventral muscle and 9.1 ng/g in axial muscle. As to marine fish, snubnose pompano (Trachinotus blochii) showed significantly higher levels of DDT and its metabolites (1018 ng/g in ventral and 409 ng/g wet wt in axial tissues) than all other marine fish species. The overall concentrations of PAHs in marine fish species were 15.5-57.0 ng/g (axial muscle) and 18.1-118 ng/g wet wt (ventral muscle) where yellow seafin (Acanthopeyrus latus) and golden threadfin bream (Nemipterus virgatus) exhibited the highest concentrations of PAHs in the axial and ventral muscles, respectively. In general, results showed that levels of PAHs in Hong Kong market fish was low and do not expect to cause any concern for human consumption. However, the levels of DDTs in fish samples ranged from 1.10 to 1018 ng/g wet wt, and based on a fish consumption rate of 142.2g/day to calculate the screening value of 14.4 ng/g wet wt for human consumption (USEPA, 2000. Guidance for assessing chemical contaminant, data for use in fish advisories, vol. 1: fish sampling and analysis, third ed. EPA 823-R-95-007. Office of Water, Washington, DC), there were 9 out of 20 (45%) muscle samples of freshwater fish species and 14 out of 20 (70%) muscle samples of marine fish species had elevated levels of DDTs exceeded the screening value. It was also suggested to use ventral muscle for detecting concentrations of persistent organic pollutants in fish. PMID:16870232

Cheung, K C; Leung, H M; Kong, K Y; Wong, M H

2007-01-01

304

Predation risk assessment by larval reef fishes during settlement-site selection  

Science.gov (United States)

Predation rates of marine species are often highest during the transition from the pelagic to the benthic life stage. Consequently, the ability to assess predation risk when selecting a settlement site can be critical to survival. In this study, pairwise choice trials were used to determine whether larvae of three species of anemonefish ( Amphiprion melanopus, A. percula and Premnas biaculeatus) are able to (1) assess the predation risk of potential anemone settlement sites through olfactory cues alone and (2) alter their settlement choices depending on the options available (host or non-host anemone). When predation risk was assessed with host and non-host anemone species independently, all species of anemonefish significantly chose the odor associated with the low-risk settlement option over the high-risk site. Most importantly, all species of anemonefish selected water with olfactory cues from their host anemone regardless of predation risk when paired against non-host anemone odor. These results demonstrate that larval reef fishes can use olfactory cues for complex risk assessment during settlement-site selection; however, locating the correct habitat is the most important factor when selecting a settlement site.

Dixson, D. L.

2012-03-01

305

Probabilistic maturation reaction norms assessed from mark-recaptures of wild fish in their natural habitat.  

Science.gov (United States)

Reaction norms are a valuable tool in evolutionary biology. Lately, the probabilistic maturation reaction norm approach, describing probabilities of maturing at combinations of age and body size, has been much applied for testing whether phenotypic changes in exploited populations of fish are mainly plastic or involving an evolutionary component. However, due to typical field data limitations, with imperfect knowledge about individual life histories, this demographic method still needs to be assessed. Using 13 years of direct mark-recapture observations on individual growth and maturation in an intensively sampled population of brown trout (Salmo trutta), we show that the probabilistic maturation reaction norm approach may perform well even if the assumption of equal survival of juvenile and maturing fish does not hold. Earlier studies have pointed out that growth effects may confound the interpretation of shifts in maturation reaction norms, because this method in its basic form deals with body size rather than growth. In our case, however, we found that juvenile body size, rather than annual growth, was more strongly associated with maturation. Viewed against earlier studies, our results also underscore the challenges of generalizing life-history patterns among species and populations. PMID:24967078

Olsen, Esben M; Serbezov, Dimitar; Vøllestad, Leif A

2014-05-01

306

Flow cytometric assessment of DNA damage in the fish Catla catla (Ham.) exposed to gamma radiation  

International Nuclear Information System (INIS)

Environmental mutagens such as ionizing radiation and chemicals induce DNA damage in a wide variety of organisms. The International Commission on Radiological Protection (lCRP) has recently emphasized the need to protect non-human biota from the potential effects of ionizing radiation. Radiation exposures to non-humans can occur as a result of low-level radioactive discharges into the environment. Molecular genetic effects at low-level radiation exposures are largely unexplored and systematic studies using sensitive biomarkers are required to assess DNA damage in representative non-human species. The objective of the study was to detect DNA damage in the fish Catla catla exposed to gamma radiation using flow cytometry at different time intervals. Increases in the coefficient of variation (CV) of the G0/G1 peak, indicating abnormal DNA distributions were observed in fish exposed to gamma radiation than in controls. Significant increase in the CV was observed from day 12-90 and thereafter decreased. This increase in CV might be due to DNA damage in the cell populations at G0/G1 phase or deletions and duplications caused by improper repair of chromosomes in the cell-cycle machinery. Ionizing radiation induced cell-cycle perturbations and apoptosis were also observed after gamma radiation exposure. (author)

307

Stock Market Liberalization, Stock Market Performance and Economic Growth in Kenya  

Directory of Open Access Journals (Sweden)

Full Text Available The study empirically examined whether stock market liberalization improves the functioning of domestic stock market and accelerates economic growth in Kenya. The study also assessed the kind of relationship between liberalization, stock market performance and economic growth in Kenya. Liberalization was assessed by stock market capitalization while turnover was used to asses stock market performance. The study used quarterly time series data collected through secondary sources and covered a period of 22 years from January, 1991 to December, 2012. The study utilized econometric techniques of Vector autoregressive and Granger Causality Tests to investigate the relationships. The results displayed a one way causality that runs from stock market development to economic growth. The results also show that stock market liberalization indirectly impacts on economic growth through investment. The study found that stock market liberalization has a significant positive impact on the economic growth in Kenya.  

Isaac Kimunio Kinuthia

2014-03-01

308

From fish chemical characterisation to the benefit-risk assessment--part A.  

Science.gov (United States)

Proximate composition, fatty acid profile, cholesterol, ?-tocoferol content and essential (K, Na, Cl, S, Mg, Ca, Zn, Cu, Fe, Mn, and Se) and contaminant element (Hg/MeHg, Cd, Pb, and As) levels in silver scabbardfish (Lepidopus caudatus), hake (Merluccius merluccius), and ray (Raja spp.) were investigated. Results showed that these species contain high protein, low cholesterol and energy levels, being its consumption recommended. Polyunsaturated fatty acids (PUFA) were the dominant group of the fatty acids, being 80% of the n-3 family. Attending to the dietary reference intakes (DRIs), these fish species are a good source of Se and the other minerals can give a relevant contribution to the DRIs in a balanced diet. More than one weekly meal of silver scabbardfish has to be avoided due to the organic mercury concentration. More accurate dietary recommendations require a probabilistic assessment, which will be the focus of this study's Part B. PMID:23199996

Afonso, Cláudia; Lourenço, Helena Maria; Cardoso, Carlos; Bandarra, Narcisa Maria; Carvalho, Maria Luísa; Castro, Matilde; Nunes, Maria Leonor

2013-04-15

309

Assessing the impact of non-native freshwater fishes on native species using relative weight  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the research was to test relative weight (Wr, a condition index which allows evaluation of fish well-being, as a tool to investigate the impact of the presence of non native species (NNS on the condition of the key native species (NS of the Tiber River basin (Italy: Barbustyberinus Bonaparte, Leuciscus cephalus (Linnaeus, Leuciscus lucumonis Bianco, Rutilus rubilio (Bonaparte and Telestes muticellus (Bonaparte. By means of Canonical Correlation Analysis, data from 130 sampling sites, distributed throughout Tiber River basin, were examined. Wr of NS was related to densities of NNS and to environmental variables. Moreover, the correlation between Wr of NS and density of NNS was investigated through linear regression analysis and covariance analysis. Preliminary results encourage the use of Wr as a tool to assess the relationship between NS and ecological factors (such as the presence of NNS and to explain the changes that occur along the longitudinal gradient of a river.

Giannetto D.

2012-01-01

310

Epizootics of wild fish induced by farm fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The continuing decline of ocean fisheries and rise of global fish consumption has driven aquaculture growth by 10% annually over the last decade. The association of fish farms with disease emergence in sympatric wild fish stocks remains one of the most controversial and unresolved threats aquaculture poses to coastal ecosystems and fisheries. We report a comprehensive analysis of the spread and impact of farm-origin parasites on the survival of wild fish populations. We mathematically coupled...

Krkos?ek, Martin; Lewis, Mark A.; Morton, Alexandra; Frazer, L. Neil; Volpe, John P.

2006-01-01

311

Do changes in environmental and fishing pressures impact marine communities? An empirical assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

P>1. The development of ecosystem approaches to environmental management implies the need to account for multiple pressures on ecosystems. Trends in multiple metrics that respond differently to changes in major environmental pressures need to be combined to evaluate the impacts of fishing and environmental changes on fish communities. 2. An exploited fish community is viewed as a three-level food chain in which the two upper levels, or functional groups, are targeted by fishing fleets, while ...

Rochet, M. J.; Trenkel, V. M.; Carpentier, A.; Coppin, F.; Sola, L. G.; Leaute, J. P.; Mahe, J. C.; Maiorano, P.; Mannini, A.; Murenu, M.; Piet, G. J.; Politou, C. Y.; Reale, B.; Spedicato, M. T.; Tserpes, G.

2010-01-01

312

Assessing disturbance from under-ice noise on fishes in boreal lakes.  

Science.gov (United States)

There are many potential sources of anthropogenic noise that can manifest under ice in boreal lakes that are within the hearing ranges of northern boreal fishes. Impacts of noise on fish can be correlated to the fish's hearing sensitivity. In general, boreal fishes have most sensitive hearing pile driving) or the potential for a sound-related disturbance ata particular time in a species life history, such as courtship or spawning, warrants further study. PMID:22278519

Cott, Peter A; Mann, David A; Higgs, Dennis M; Johnston, Tom A; Gunn, John M

2012-01-01

313

Assessment of Trace Metal Composition in Fish Samples from Nworie River  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This investigation surveyed heavy metal content of fish samples from Nworie river. The elements studied were Pb, Fe, Cd, Mn, Hg, Cu and Zn. The fish samples were collected from different locations in the river. The fish samples were analyzed for heavy metals using Atomic Absorption Spectrophotometer (AAS). The elemental toxicants Fe, Cd, Mn were identified in fresh fish specie Tilapia guineensis of mean values 3.275, 0.048 and 0.103 ppm, respectively, whereas Pb was below detection lev...

Obiji, I. A.; Alinnor, I. J.

2010-01-01

314

Exploiting Growing Stock Volume Maps for Large Scale Forest Resource Assessment: Cross-Comparisons of ASAR- and PALSAR-Based GSV Estimates with Forest Inventory in Central Siberia  

Directory of Open Access Journals (Sweden)

Full Text Available Growing stock volume is an important biophysical parameter describing the state and dynamics of the Boreal zone. Validation of growing stock volume (GSV maps based on satellite remote sensing is challenging due to the lack of consistent ground reference data. The monitoring and assessment of the remote Russian forest resources of Siberia can only be done by integrating remote sensing techniques and interdisciplinary collaboration. In this paper, we assess the information content of GSV estimates in Central Siberian forests obtained at 25 m from ALOS-PALSAR and 1 km from ENVISAT-ASAR backscatter data. The estimates have been cross-compared with respect to forest inventory data showing 34% relative RMSE for the ASAR-based GSV retrievals and 39.4% for the PALSAR-based estimates of GSV. Fragmentation analyses using a MODIS-based land cover dataset revealed an increase of retrieval error with increasing fragmentation of the landscape. Cross-comparisons of multiple SAR-based GSV estimates helped to detect inconsistencies in the forest inventory data and can support an update of outdated forest inventory stands.

Christian Hüttich

2014-07-01

315

Assessment of various sublethal chromium hexavalent concentrations in ambient water, fish muscles and progeny (larvae)  

International Nuclear Information System (INIS)

Chromium accumulation estimated on atomic absorption spectrophotometer increased significantly (P larvae (21 to 67 micro g/ml), while in their corresponding control group no chromium was detected in ambient water and fish larvae. 0.21 to 0.5 micro g/ml Cr (VI) was detected in fish muscles naturally acquired by fish for growth. (author)

316

Toxic metal, micro and macronutrient assessment in fish most consumed by Iguape community, Sao Paulo state, Brazil  

Energy Technology Data Exchange (ETDEWEB)

It is well-known that, fish is an important source of protein for populations around the world. As such, fish consumption has increased because it is a healthy and low cholesterol source of protein and other nutrients. The city of Iguape, in the extreme south of the Sao Paulo State coast, is located in a well-preserved Atlantic Forest region. During the last two centuries the city suffered from drastic environmental changes, reinforcing the importance of environmental monitoring in this region. In the present study, 23 samples of the three most consumed fish species by the Iguape city population were analyzed. Fish samples were bought at local markets, conditioned in isothermic boxes in crushed ice (-4 deg C) and then identified before registering the biometric information (total length, total weight and body weight). The following micro and macronutrients As, Br, Ca, Co, Fe, K, Na, Rb, Sc, Se and Zn concentration in muscle from 02 predatory fish species Macrodon ancylodon (King weakfish - Pescada) and Centropomus parallelus (Fat snook - Robalo peba) and one detritivorus species: Anchoviella lepidentostole (Broadband anchovy - Manjuba) were assessed by INAA. Toxic metals Cd, Hg and Pb were also evaluated by AAS. Statistical correlation between element concentrations and fish species were tested. (author)

Favaro, Deborah I.T.; Vieira, Andre S.; Bordon, Isabella C.A.C., E-mail: defavaro@ipen.br, E-mail: isabella.bordon@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Farias, Luciana A., E-mail: lufarias2@yahoo.com.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil); Braga, Elisabete S., E-mail: edsbraga@usp.br [Universidade de Sao Paulo (LABNUT/IO/USP), Sao Paulo, SP (Brazil). Instituto Oceanografico

2013-07-01

317

Toxic metal, micro and macronutrient assessment in fish most consumed by Iguape community, Sao Paulo state, Brazil  

International Nuclear Information System (INIS)

It is well-known that, fish is an important source of protein for populations around the world. As such, fish consumption has increased because it is a healthy and low cholesterol source of protein and other nutrients. The city of Iguape, in the extreme south of the Sao Paulo State coast, is located in a well-preserved Atlantic Forest region. During the last two centuries the city suffered from drastic environmental changes, reinforcing the importance of environmental monitoring in this region. In the present study, 23 samples of the three most consumed fish species by the Iguape city population were analyzed. Fish samples were bought at local markets, conditioned in isothermic boxes in crushed ice (-4 deg C) and then identified before registering the biometric information (total length, total weight and body weight). The following micro and macronutrients As, Br, Ca, Co, Fe, K, Na, Rb, Sc, Se and Zn concentration in muscle from 02 predatory fish species Macrodon ancylodon (King weakfish - Pescada) and Centropomus parallelus (Fat snook - Robalo peba) and one detritivorus species: Anchoviella lepidentostole (Broadband anchovy - Manjuba) were assessed by INAA. Toxic metals Cd, Hg and Pb were also evaluated by AAS. Statistical correlation between element concentrations and fish species were tested. (author)

318

Integrating the fish embryo toxicity test as triad element for sediment toxicity assessment based on the water framework directive approach  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The objective of this study was to complement analyses according to the European Union Water Framework Directive (WFD) with a sediment toxicity analysis as part of an integrated river assessment. To this end, Hessian water courses were analyzed using the sediment quality triad concept according to Chapman with chemical analyses, in situ effect evaluations, and ecotoxicological assessments. For the ecotoxicological assessment (fish embryo toxicity test with Danio rerio), a new evaluation scheme was developed, the fish teratogenicity index (FTI), that allows for a classification of sediments into ecological quality classes compliant to the WFD. Materials and methods sediment and macrozoobenthos samples were taken from tributaries of the rivers Fulda and Lahn. Sediments were characterized regarding particle size, carbon, heavy metals, and polyaromatic hydrocarbon content. Macroinvertebrate samples were taken via multi-habitat sampling. The fish embryo toxicity test with D. rerio was conducted as a contact assay on the basis of DIN 38415-6. Results and discussion The integrated assessment indicated a significant influence of heavy metals and carbon content on macroinvertebrate communities. The bioaccessibility of sediment pollutants were clearly demonstrated by the FTI, which showed a wide range of adverse effects. A significant linear relationship between metals and the FTI was detected. However, there was no statistically significant evidence that macroinvertebrate communities were affected by the hydromorphological quality clements at the sampling sites. Conclusions The new scheme for the assessment of fish embryo toxicity test was successfully applied. The results suggest that sediment compounds impact macroinvertebrate communities and early development of fish. It demonstrates that the quality of sediments should be evaluated on a routine basis as part of an integrated river assessment. (orig.)

Bartzke, Mariana [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Dept. Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Leipzig (Germany); Delov, Vera [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Ecotoxicology, Fraunhofer Inst. for Molecular Biology and Applied Ecology IME, Aachen (Germany); Stahlschmidt-Allner, Petra; Allner, Bernhard [Gobio GmbH, Aarbergen/Kettenbach (Germany); Oehlmann, Joerg [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany)

2010-04-15

319

Diet Composition and Selectivity in O+ Perch (Perca fluviatilis L. and its Competition with Adult Fish and Carp (Cyprinus carpio L. Stock in Pond Culture  

Directory of Open Access Journals (Sweden)

Full Text Available Food composition and selectivity of 0+ perch (Perca fluviatilis were studied under the experimental pond conditions during the growing season in 2000. The diet of perch fry consisted mainly of chironomid larvae and pupae and zooplankton, mainly cladocerans (Bosmina longirostris, Chydorus sp., Ceriodaphnia sp., Alona sp. and copepods. Both chironomids and cladocerans were consumed with positive selectivity. The food items of lesser importance were water beetles (genera Rhantus, Hydrobius and Hydroporus, water bugs Corixa affinis and mayfly larvae Caenis sp. Chironomid larvae were most important food items also in the diet of both adult perch and 2+ carp. Also 0+ perch contributed considerably to the diet of adult perch and benthic food resources (bryozoans and organic debris including supplied feed cereals were of biggest importance for common carp. The perch competes with parental fish and common carp for approximately one third of available food items, whilst adult perch and carp compete for a half of them.

Zden?k Adámek

2004-03-01

320

Assessing variation in the potential susceptibility of fish to pharmaceuticals, considering evolutionary differences in their physiology and ecology.  

Science.gov (United States)

Fish represent the planet's most diverse group of vertebrates and they can be exposed to a wide range of pharmaceuticals. For practical reasons, extrapolation of pharmaceutical effects from 'model' species to other fish species is adopted in risk assessment. Here, we critically assess this approach. First, we show that between 65% and 86% of human drug targets are evolutionarily conserved in 12 diverse fish species. Focusing on nuclear steroid hormone receptors, we further show that the sequence of the ligand binding domain that plays a key role in drug potency is highly conserved, but there is variation between species. This variation for the oestrogen receptor, however, does not obviously account for observed differences in receptor activation. Taking the synthetic oestrogen ethinyloestradiol as a test case, and using life-table-response experiments, we demonstrate significant reductions in population growth in fathead minnow and medaka, but not zebrafish, for environmentally relevant exposures. This finding contrasts with zebrafish being ranked as more ecologically susceptible, according to two independent life-history analyses. We conclude that while most drug targets are conserved in fish, evolutionary divergence in drug-target activation, physiology, behaviour and ecological life history make it difficult to predict population-level effects. This justifies the conventional use of at least a 10× assessment factor in pharmaceutical risk assessment, to account for differences in species susceptibility. PMID:25405965

Brown, A R; Gunnarsson, L; Kristiansson, E; Tyler, C R

2014-11-19

 
 
 
 
321

The IUCN Red List of Threatened Species: an assessment of coral reef fishes in the US Pacific Islands  

Science.gov (United States)

Widespread declines among many coral reef fisheries have led scientists and managers to become increasingly concerned over the extinction risk facing some species. To aid in assessing the extinction risks facing coral reef fishes, large-scale censuses of the abundance and distribution of individual species are critically important. We use fisheries-independent data collected as part of the NOAA Pacific Reef Assessment and Monitoring Program from 2000 to 2009 to describe the range and density across the US Pacific of coral reef fishes included on The International Union for the Conservation of Nature's (IUCN) 2011 Red List of Threatened Species. Forty-five species, including sharks, rays, groupers, humphead wrasse ( Cheilinus undulatus), and bumphead parrotfish ( Bolbometopon muricatum), included on the IUCN List, were recorded in the US Pacific Islands. Most species were generally rare in the US Pacific with the exception of a few species, principally small groupers and reef sharks. The greatest diversity and densities of IUCN-listed fishes were recorded at remote and uninhabited islands of the Pacific Remote Island Areas; in general, lower densities were observed at reefs of inhabited islands. Our findings complement IUCN assessment efforts, emphasize the efficacy of large-scale assessment and monitoring efforts in providing quantitative data on reef fish assemblages, and highlight the importance of protecting populations at remote and uninhabited islands where some species included on the IUCN Red List of Threatened Species can be observed in abundance.

Zgliczynski, B. J.; Williams, I. D.; Schroeder, R. E.; Nadon, M. O.; Richards, B. L.; Sandin, S. A.

2013-09-01

322

Assessment of Heavy Metals in the Fish Collected from the River Ravi, Pakistan  

Directory of Open Access Journals (Sweden)

Full Text Available The toxicity of heavy metals viz. aluminium (Al, arsenic (As, barium (Ba, chromium (Cr, nickel (Ni and zinc (Zn in fish at three main public fishing sites of the river Ravi viz. Shahdara bridge, Baloki headworks and Sidhnai barrage has been studied from June, 2009 to May, 2010. The concentrations of heavy metals in the body organs (gills, liver, kidney, intestine, reproductive organs, skin, muscle, fins, scales, bones, fats of three fish species viz. Catla catla, Labeo rohita and Cirrhina mrigala were determined. The present results reveal that the toxicity of metals fluctuated significantly in fish at all the three sampling stations with season. The fish samples collected from all the three sampling stations had significantly higher aluminium and zinc. However, the fish at Sidhnai barrage showed significantly lower metallic toxicity, followed by that at Baloki headworks and Shahdara bridge. Significantly higher metals were observed in fish liver, followed by that of kidney, gills, intestine, reproductive organs, skin, scales, fins, bones, muscle and fats. The accumulation of metals in carnivorous fish body organs showed significantly direct dependence on the metallic toxicity of herbivorous cyprinids. Fish liver and kidney showed significantly higher abilities for the accumulation of all metals while accumulations were lowest in fish muscle and fats. The health status of river Ravi at three main public fishing sites viz. Shahdara bridge, Baloki headworks and Sidhnai barrage, with respect to eco-toxicity of Al, As, Ba, Cr, Ni and Zn was above the recommended permissible standards.

Ghazala Jabeen*, Muhammad Javed and Hamda Azmat

2012-01-01

323

By-Catch Impacts in Fisheries: Utilizing the IUCN Red List Categories for Enhanced Product Level Assessment in Seafood LCAs  

Science.gov (United States)

Overexploitation of fish stocks causes concern not only to fisheries managers and conservation biologists, but also engages seafood consumers; more integrated product perspectives would be useful. This could be provided by life cycle assessment (LCA); however, further complements of present LCA methodology are needed to assess seafood production, one being by-catch impacts. We studied the scientific rationale behind using the IUCN Red List of Threatened Species™ for assessment of impacts relating to fish species’ vulnerability. For this purpose, the current Red List status of marine fish in Sweden was compared to the advice given in fisheries as well as key life history traits known to indicate sensitivity to high fishing pressure. Further, we quantified the amount of threatened fish (vulnerable, endangered, or critically endangered) that was discarded in demersal trawl fisheries on the Swedish west coast. The results showed that not only did the national Red List of marine fish have a high consistency with advice given in fisheries and indices of vulnerability, the different fishing practices studied were also found to have vastly different amounts of threatened fish discarded per kilo landing. The suggested approach is therefore promising as a carrier of aggregated information on the extent to which seafood production interferes with conservation priorities, in particular for species lacking adequate stock assessment. To enable extensive product comparisons, it is important to increase coverage of fish species by the global IUCN Red List, and to reconsider the appropriate assessment unit (species or stocks) in order to avoid false alarms.

Hornborg, Sara; Svensson, Mikael; Nilsson, Per; Ziegler, Friederike

2013-11-01

324

Fugitive Salmon: Assessing the Risks of Escaped Fish from Net-Pen Aquaculture  

Science.gov (United States)

This peer-reviewed resource from BioScience journal is the risks associated with aquaculture.The farming of salmon and other marine finfish in open net pens continues to increase along the world's coastlines as the aquaculture industry expands to meet human demand. Farm fish are known to escape from pens in all salmon aquaculture areas. Their escape into the wild can result in interbreeding and competition with wild salmon and can facilitate the spread of pathogens, thereby placing more pressure on already dwindling wild populations. Here we assess the ecological, genetic, and socioeconomic impacts of farm salmon escapes, using a risk-assessment framework. We show that risks of damage to wild salmon populations, ecosystems, and society are large when salmon are farmed in their native range, when large numbers of salmon are farmed relative to the size of wild populations, and when exotic pathogens are introduced. We then evaluate the policy and management options for reducing risks and discuss the implications for farming other types of marine finfish.

ROSAMOND NAYLOR, KJETIL HINDAR, IAN A. FLEMING, REBECCA GOLDBURG, SUSAN WILLIAMS, JOHN VOLPE, FRED WHORISKEY, JOSH EAGLE, DENNIS KELSO, and MARC MANGEL (;)

2005-05-01

325

Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates?  

DEFF Research Database (Denmark)

Mortality of small pelagic fish due to marine mammals is generally considered to be low compared with other sources of mortality. With recent recoveries of marine mammal predators worldwide, this may no longer hold. The grey seal (Halichoerus grypus) population in the Bothnian Sea has increased fivefold since 1985. Its main prey, herring (Clupea harrengus), is a key species for fisheries in the region. Yet, current stock assessments assume constant natural mortality, leading to a risk of biased stock estimates with increasing predation and misleading analyses of herring population dynamics. We estimated grey seal predation from diet data and reanalysed herring spawning stock biomass (SSB) during 1973–2009. Accounting for predation increased the herring SSB 16% (maximum 19%), but this was within the confidence intervals when ignoring predation. Although mortality in older individuals was inflated when accounting for seal predation, this did not change the conclusions about drivers of herring dynamics. Accounting for grey seal predation is important for abundance estimates of old herring, but currently not for SSB estimates, given the great uncertainties in the standard assessment. The grey seal impact on Bothnian Sea herring will need to be reassessed if stock age composition, grey seal feeding preferences, or total stock development change

Gårdmark, Anna; Östman, Örjan

2012-01-01

326

Analyses of trawling track and fishing activity based on the data of Vessel Monitoring System (VMS): A case study of the single otter trawl vessels in the Zhoushan fishing ground  

Science.gov (United States)

The original purpose of Vessel Monitoring System (VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to improve the accuracy of fisheries stock assessment. In this paper, we simulated the trawl trajectory under different time intervals using the cubic Hermite spline (cHs) interpolation method based on the VMS data of 8 single otter trawl vessels (totally 36000 data items) fishing in Zhoushan fishing ground from September 2012 to December 2012, and selected the appropriate time interval. We then determined vessels' activities (fishing or non-fishing) by comparing VMS speed data with the corresponding speeds from logbooks. The results showed that the error of simulated trajectory greatly increased with the increase of time intervals of VMS data when they were longer than 30 minutes. Comparing the speeds from VMS with those from the corresponding logbooks, we found that the vessels' speeds were between 2.5 kn and 5.0 kn in fishing. The cHs interpolation method is a new choice for improving the accuracy of estimation of sailing trajectory, and the VMS can be used to determine the vessels' activities with the analysis of their trajectories and speeds. Therefore, when the fishery information is limited, VMS can be one of the important data sources for fisheries stock assessment, and more attention should be paid to its construction and application to fisheries stock assessment and management.

Wang, Yang; Wang, Yingbin; Zheng, Ji

2014-10-01

327

Estimation of sport fish harvest for risk and hazard assessment of environmental contaminants  

International Nuclear Information System (INIS)

Consumption of contaminated fish flesh can be a significant route of human exposure to hazardous chemicals. Estimation of exposure resulting from the consumption of fish requires knowledge of fish consumption and contaminant levels in the edible portion of fish. Realistic figures of sport fish harvest are needed to estimate consumption. Estimates of freshwater sport fish harvest were developed from a review of 72 articles and reports. Descriptive statistics based on fishing pressure were derived from harvest data for four distinct groups of freshwater sport fish in three water types: streams, lakes, and reservoirs. Regression equations were developed to relate harvest to surface area fished where data bases were sufficiently large. Other aspects of estimating human exposure to contaminants in fish flesh that are discussed include use of bioaccumulation factors for trace metals and organic compounds. Using the bioaccumulation factor and the concentration of contaminants in water as variables in the exposure equation may also lead to less precise estimates of tissue concentration. For instance, muscle levels of contaminants may not increase proportionately with increases in water concentrations, leading to overestimation of risk. In addition, estimates of water concentration may be variable or expressed in a manner that does not truly represent biological availability of the contaminant. These factors are discussed. 45 refs., 1 fig., 7 tabsfig., 7 tabs

328

Carbon stock assessment for a forest-to-coffee conversion landscape in Sumber-Jaya (Lampung, Indonesia): from allometric equations to land use change analysis  

Energy Technology Data Exchange (ETDEWEB)

The change in stored carbon (C) stocks was assessed for a 700 km{sup 2} area where forest cover decreased from 60% to 10% in the last 30 years. At the same time, the area under coffee increased from 7% to 70% with a gradual evolution from open 'sun coffee' systems to multi-strata 'shade coffee' systems that provide a partial compensation for C loss. The use of a generic tropical forest rather than tree-specific allometric equation can lead to substantial (up to 100%) overestimates of aboveground biomass depending on wood density and tree shape. In the 1970 1984 period, while forest cover was reduced from 59.5% to 19.7%, the landscape lost on average 6.8 Mg C ha{sup -1} a{sup -1}. In the 1984 2000 period forest cover was further reduced to 12.6%, but the landscape lost only 0.39 Mg C ha{sup -1} a{sup -1}, as forest loss was partially compensated by an increase in shade coffee systems. Conversion of all current sun coffee to shade coffee systems while protecting the remaining forest, could increase average landscape level C stocks by 10 Mg ha{sup -1} over a time frame of say 20 years, or 0.5 Mg C ha{sup -1} a{sup -1}.

Meine van Noordwijk; Subekti Rahayu; Kurniatun Hairiah; Y.C. Wulan; A. Farida; Bruno Verbist [International Centre for Research in Agroforestry (ICRAF) SE Asia, Bogor (Indonesia)

2002-07-01

329

Stock assessment and management implications of horse mackerel ( Trachurus japonicus) in Korean waters, based on the relationships between recruitment and the ocean environment  

Science.gov (United States)

This study presents an example of horse mackerel ( Trachurus japonicus) stock to demonstrate that marine environmental factors are important in stock assessment for the new Korean Total Allowable Catch (TAC)-based fisheries management system. The estimated survival rate ( S) of horse mackerel ranged from 0.25 to 0.36. The instantaneous coefficient of natural mortality ( M) was 0.48/year, and the age at first capture was 0.83 year. Annual biomass of horse mackerel in Korean waters was estimated by a biomass-based cohort analysis using annual catch in weight at age during 1965-1995. Yield-per-recruit and spawning biomass-per-recruit were estimated under various harvest strategies at Fmax, F0.1, F30% and F40%. A method for estimating acceptable biological catch (ABC) is proposed for dealing with the large differences in the quality and quantity of information and data available. Using recruitment of horse mackerel estimated from various spawner-recruitment relationship models combined with salinity, volume transport, and zooplankton biomass as environmental factors, the ABC under the best information available was estimated to range from 3100 to 3800 mt.

Zhang, Chang Ik; Lee, Jae Bong

330

Mercury biomagnification in subtropical reservoir fishes of eastern China.  

Science.gov (United States)

Little is known about mercury (Hg) biomagnification in the subtropics, aquatic systems with high species diversity resulting in complex food webs. High atmospheric Hg emissions and ubiquitous reservoir fisheries may lead to elevated Hg bioaccumulation in Chinese freshwater fishes. However, stocking practices using fast-growing species can result in low fish total Hg (THg) concentrations. Here, we describe Hg transfer within the fish food web of a large subtropical reservoir, Qiandao Hu (Xin'anjiang reservoir) situated in eastern China. We measured food web Hg biomagnification and THg concentrations in 33 species of stocked and wild fishes. Mercury concentrations in most fishes were low, though we also found high Hg concentrations in wild top predators. The food web structure, assessed using stable isotopes of carbon (?(13)C) and nitrogen (?(15)N), demonstrated a high degree of omnivory and a long food chain. THg concentrations were highly correlated with fish ?(15)N values. The regression of log10THg against ?(15)N revealed the overall Hg biomagnification rate was low. This study shows that where long food chains exist in subtropical reservoirs, elevated Hg accumulation in top predators can occur despite a low Hg biomagnification rate. PMID:24337794

Razavi, N Roxanna; Qu, Mingzhi; Jin, Binsong; Ren, Wenwei; Wang, Yuxiang; Campbell, Linda M

2014-03-01

331

In situ assessment of a neotropical fish to evaluate pollution in a river receiving agricultural and urban wastewater.  

Science.gov (United States)

We aimed to assess the quality of a midsize river that receives agricultural and urban wastewater. Nuclear abnormalities (NA), comet assays of blood and gills, and gill histopathology were evaluated in fish Astyanax aff. paranae during the summer and winter 2011 at three sites in Paraná State, Brazil: (1) a biological reserve (Rebio-reference area); (2) an agricultural site; (3) a downstream site that accumulates agricultural and urban effluents. We found the highest effects of pollutants in fish at the downstream site during the summer. The agricultural site showed an intermediate damage rate, and fish at Rebio generally had the least damage, with the exception of NA. Despite conflicting results from the biomarkers used, we observed an increase in damage associated with the accumulation of pollutants. Pesticides are probable xenobiotics in the agricultural area. Additionally, metals and substances such as pharmaceuticals and ammonia may be present at the downstream site. PMID:25319198

Ghisi, Nédia de Castilhos; de Oliveira, Elton Celton; Fávaro, Luís Fernando; Silva de Assis, Helena Cristina; Prioli, Alberto José

2014-12-01

332

Analysis of fish DNA biomarkers as a molecular-level approach for ecological health assessments in an urban stream.  

Science.gov (United States)

This study was performed to determine the ecosystem health of an urban stream using DNA damage biomarkers of sentinel fish species along with chemical analyses of water and sediments in the impacted and reference zones. The results based on single-cell gel electrophoresis showed that the extent of DNA damage was significantly elevated in the polluted zone. The severity of DNA damage in the impacted zone was largely attributed to high levels of heavy metals, such as As, Zn, Pb, and Ni. The DNA damage biomarker in benthic fish was sensitive to habitat change, which suggested that this fish species and biomarker are excellent tools for risk assessment. The acute toxicity tests demonstrated that SCGE was sufficient to reflect the different genotypes and pollution statuses and to propose the possibility of zebrafish erythrocytes as competitive materials. PMID:25260997

Kang, Nami; Kang, Han-Il; An, Kwang-Guk

2014-11-01

333

Hexavalent chromium in fish from the Sepetiba Bay in Rio de Janeiro, Brazil: a risk assessment to human health  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Certain metals, among them hexavalent chromium influence the stability of ecosystems and cause adverse effects on human health. Thus, this study aimed to estimate a risk model of human health associated with fish consumption from the Sepetiba Bay. Methodology: This risk assessment methodology was developed by the United States Environmental Protection Agency (USEPA. The models were implemented using the USEPA toxicological databases and samples from the Sepetiba Bay, Rio de Janeiro. Results: The intoxication and carcinogenic risk estimated for fish consumption of M. furnieri and C. acoupa species were considered small. Conclusion: Based on the analysis, we conclude that the toxicological risk or carcinogenic injury to health due to fish consumption with high levels of cromo6+ coming from Sepetiba Bay is low. Still, it emphasizes the validity of utilizing monitoring methods in coastal environments, for health and environmental control.

Carla da Costa Cruz

2011-12-01

334

Assessment of Heavy Metals in the Fish Collected from the River Ravi, Pakistan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The toxicity of heavy metals viz. aluminium (Al), arsenic (As), barium (Ba), chromium (Cr), nickel (Ni) and zinc (Zn) in fish at three main public fishing sites of the river Ravi viz. Shahdara bridge, Baloki headworks and Sidhnai barrage has been studied from June, 2009 to May, 2010. The concentrations of heavy metals in the body organs (gills, liver, kidney, intestine, reproductive organs, skin, muscle, fins, scales, bones, fats) of three fish species viz. Catla catla, Labeo rohita and Cirrh...

Ghazala Jabeen, Muhammad Javed And Hamda Azmat

2012-01-01

335

Baseline assessment of the reef fish assemblage from Cagarras Archipelago, Rio de Janeiro, southeastern Brazil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The extensive Brazilian coast comprises diverse reef fish communities. Here, we report a pioneer study on the reef fish community composition of the Cagarras Archipelago. This rocky reef system consists of a small group of coastal islands 5 km south off Ipanema Beach, Rio de Janeiro city, Brazil. A relatively diverse and disturbed fish community (99 species from 39 families) was found in this archipelago. Two different visual census techniques were utilized and a large difference was observed...

Rangel, Carlos A.; Chaves, Lai?s C. T.; Cassiano Monteiro-Neto

2007-01-01

336

Screening level dose rate assessment of fishes exposed to artificial radionuclides of the Beloyarskoe storage pond  

International Nuclear Information System (INIS)

Aquatic biota in the Beloyarskoe storage pond of the nuclear power station are exposed to radioactivity released from the fast-breeder reactor. A simple conservative screening level model was used to estimate absorbed (whole body) dose rates for aquatic organisms. Four species of fishes were studied, (non-bottom-feeding fish, and bottom-feeding fish). The analysis was based on radionuclide concentrations reported in papers published by Russian Academy of Sciences. (authors)

337

Refugia of marine fish in the northeast Atlantic during the last glacial maximum: concordant assessment from archaeozoology and palaeotemperature reconstructions  

Directory of Open Access Journals (Sweden)

Full Text Available Archaeozoological finds of the remains of marine and amphihaline fish from the Last Glacial Maximum (LGM ca. 21 ka ago show evidence of very different species ranges compared to the present. We have shown how an ecological niche model (ENM based on palaeoclimatic reconstructions of sea surface temperature and bathymetry can be used to effectively predict the spatial range of marine fish during the LGM. The results indicate that the ranges of marine fish species now in northwestern Europe were displaced significantly southwards from the modern distribution, challenging an existing paradigm of marine glacial refugia. The model presents strong evidence that there was an invasion of important fish through the Straits of Gibraltar in glacial times, where they were exploited by Palaeolithic human populations around the western Mediterranean Sea. The ENM results are important for ongoing studies of molecular ecology that aim to assess marine glacial refugia from the genetic structure of living populations, and they pose questions about the genetic identity of vanished marine populations during the LGM. Economically, the approach may be used to understand how the ranges of exploited fish species may be displaced with the future climate warming. The research presents a challenge for future archaeozoological work to delimit the glacial refugia and to verify palaeoclimatic reconstructions based on deep-sea core records.

A. J. Kettle

2011-03-01

338

Stocking density and Piscirickettsia salmonis infection effect on Patagonian blennie (Eleginops maclovinus, Cuvier 1830) skeletal muscle intermediate metabolism.  

Science.gov (United States)

The need to expand aquaculture production has led to other fish to be considered as potential species for culture, such as the sub-Antarctic notothenioid Eleginops maclovinus (Valenciennes, 1830). The aim of this study was to determine the cumulative effect of density and pathogen infection by protein extract of Piscirickettsia salmonis on skeletal muscle metabolism. In a first experiment, specimens were submitted to three different stocking densities: (1) 3.1 kg m(-3), (2) 15 kg m(-3) and (3) 60 kg m(-3), for a period of 10 days. In a second experiment, metabolic changes caused by an infection of P. salmonis protein extract (a single injection of 0.5 ?L P. salmonis protein extract g body weight(-1) was inoculated in the fish) and its combined effect with stocking density was assessed during a period of 10 days. This study concludes that stress caused by high stocking density led to the reorganization of some metabolic routes to fulfill skeletal muscle energy needs. Furthermore, infection response by pathogen P. salmonis differed when stocking density increased, suggesting an increase of energy needs with density in skeletal muscle of infected fish. PMID:25034336

Vargas-Chacoff, L; Ortíz, E; Oyarzún, R; Martínez, D; Saavedra, E; Sá, R; Olavarría, V; Nualart, D; Yáñez, A; Bertrán, C; Mancera, J M

2014-12-01

339

Energy and economic assessment of a solar absorption refrigeration plant in a fish processing factory. A case study in Sicily  

Energy Technology Data Exchange (ETDEWEB)

The aim of the study is the energy and economic assessment of an application of solar cooling for industrial refrigeration in a fish processing factory located in Sicily. The base case is an existing plant with ammonia vapour compression machine. The use of an absorption refrigeration plant powered by parabolic solar collectors is considered as an alternative solution. The energy assessment of the considered system is carried out through detailed simulations for different collector surface and heat storage volume. In order to assess the best configuration of the solar refrigeration system in term of energy and economic performances, a sensitivity analysis is performed. (orig.)

Beccali, M.; Di Pietra, B.; Finocchiaro, P.; Messineo, A.; Panno, D. [Univ. degli Studi di Palermo (Italy). Dipt. di Ricerche Energetiche ed Ambientali

2007-07-01

340

Multibiomarker approach in fish to assess the impact of pollution in a large Brazilian river, Paraiba do Sul  

Energy Technology Data Exchange (ETDEWEB)

This article examines the advantages of the use of biomarkers as environmental indicators by applying it to Paraiba do Sul watershed, one of the most important Brazilian water bodies, which is in a critical environmental situation. We use a multibiomarker approach in fish as an integrated strategy to assess the impact of pollution. It comprehends a general biomarker of fish health, the condition factor (CF), and specific biomarkers of contaminant exposure such as metallothionein (MT), acetylcholinesterase (AChE) activity and biliary polycyclic aromatic hydrocarbons (PAH) metabolites. Our results revealed different effects in the fish from diverse locations with varying degrees of pollution. Furthermore, fish located just upstream of the water-treatment plant of the metropolitan area of Rio de Janeiro has shown to be affected by metals. This study indicates the usefulness of integrating a set of biomarkers to define the effects of anthropogenic inputs in aquatic bodies under complex polluted situations. - Integrated approach using biomarkers proofs suitable for environmental assessment of a diversely polluted river.

Linde-Arias, Ana Rosa [Laboratorio de Toxicologia, Centro de Estudos da Saude do Trabalhador e Ecologia Humana, Escola Nacional de Saude Publica Sergio Arouca, Fundacao Oswaldo Cruz, Leopoldo Bulhoes, 1480, Rio de Janeiro (Brazil)], E-mail: arlinde@ensp.fiocruz.br; Inacio, Alan F.; Novo, Leonardo A.; Alburquerque, Carla de; Moreira, Josino C. [Laboratorio de Toxicologia, Centro de Estudos da Saude do Trabalhador e Ecologia Humana, Escola Nacional de Saude Publica Sergio Arouca, Fundacao Oswaldo Cruz, Leopoldo Bulhoes, 1480, Rio de Janeiro (Brazil)

2008-12-15

 
 
 
 
341

Risk assessment of aflatoxins B1 (AFB1) in corn arepas in Colombia and chemical risk assessment case study mercury in Fish  

International Nuclear Information System (INIS)

The power point presentation is about: Identify the pair substrate (corn, wheat and rice) - mycotoxin (DON, AFB1) higher risk for the Colombian population, based on the exposure assessment and mercury in freshwater fish from Colombia. This report answer some the following questions: what are the most consumed products in the country, which may create a risk for the Colombian population, what are the prevention and control recommendations to reduce potential contamination of the products selected, what are economic activities and their impact areas that contribute most to the incorporation of of mercury in freshwater fish from Colombia,what are the species that may pose greater accumulation of mercury and methylmercury identified , what is the risk associated with the consumption of the species, what are the preventive measures to minimize exposure from consumption of fish with mercury and methylmercury and possible intervention strategies

342

Public Review Draft: A Method for Assessing Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes in Ecosystems of the United States Under Present Conditions and Future Scenarios  

Science.gov (United States)

The Energy Independence and Security Act of 2007 (EISA), Section 712, authorizes the U.S. Department of the Interior to develop a methodology and conduct an assessment of the Nation's ecosystems focusing on carbon stocks, carbon sequestration, and emissions of three greenhouse gases (GHGs): carbon dioxide, methane, and nitrous oxide. The major requirements include (1) an assessment of all ecosystems (terrestrial systems, such as forests, croplands, wetlands, shrub and grasslands; and aquatic ecosystems, such as rivers, lakes, and estuaries), (2) an estimation of annual potential capacities of ecosystems to increase carbon sequestration and reduce net GHG emissions in the context of mitigation strategies (including management and restoration activities), and (3) an evaluation of the effects of controlling processes, such as climate change, land use and land cover, and wildlfires. The purpose of this draft methodology for public review is to propose a technical plan to conduct the assessment. Within the methodology, the concepts of ecosystems, carbon pools, and GHG fluxes used for the assessment follow conventional definitions in use by major national and international assessment or inventory efforts. In order to estimate current ecosystem carbon stocks and GHG fluxes and to understand the potential capacity and effects of mitigation strategies, the method will use two time periods for the assessment: 2001 through 2010, which establishes a current ecosystem GHG baseline and will be used to validate the models; and 2011 through 2050, which will be used to assess future potential conditions based on a set of projected scenarios. The scenario framework is constructed using storylines of the Intergovernmental Panel on Climate Change (IPCC) Special Report Emission Scenarios (SRES), along with initial reference land-use and land-cover (LULC) and land-management scenarios. An additional three LULC and land-management mitigation scenarios will be constructed for each storyline to enhance carbon sequestration and reduce GHG fluxes in ecosystems. Input from regional experts and stakeholders will be solicited to construct realistic and meaningful scenarios. The methods for mapping the current LULC and ecosystem disturbances will require the extensive use of both remote-sensing data and in-situ (for example, forest inventory data) to capture and characterize landscape-change events. For future potential LULC and ecosystem disturbances, key drivers such as socioeconomic, policy, and climate assumptions will be used in addition to biophysical data. The product of these analyses will be a series of maps for each future year for each scenario. These annual maps will form the basis for estimating carbon storage and GHG emissions. For terrestrial ecosystems, carbon storage, carbon-sequestration capacities, and GHG emissions under the current and projected future conditions will be assessed using the LULC and ecosystem-disturbance estimates in map format with a spatially explicit biogeochemical ensemble modeling system that incorporates properties of management activities (such as tillage or harvesting) and properties of individual ecosystems (such as elevation, vegetation characteristics, and soil attributes). For aquatic ecosystems, carbon burial in sediments and GHG fluxes are functions of the current and projected future stream flow and sediment transports, and therefore will be assessed using empirical modeling methods. Validation and uncertainty analysis methods described in the methodology will follow established guidelines to assess the quality of the assessment results. The U.S. Environmental Protection Agency's Level II ecoregions map (which delineates 24 ecoregions for the Nation) will be the practical instrument for developing and delivering assessment results. Consequently, the ecoregion will be the reporting unit of the assessment because the mitigation scenarios, assessment results, validation, and uncertainty analysis will be

Bergamaschi, Brian; Bernknopf, Richard; Clow, David; Dye, Dennis; Faulkner, Stephen; Forney, William; Gleason, Robert; Hawbaker, Todd; Liu, Jinxun; Liu, Shuguang; Prisley, Stephen; Reed, Bradley; Reeves, Matthew; Rollins, Matthew; Sleeter, Benjamin; Sohl, Terry; Stackpoole, Sarah; Stehman, Stephen; Striegl, Rob; Wein, Anne; Zhu, Zhi-Liang

2010-01-01

343

A hierarchical spatial framework and database for the national river fish habitat condition assessment  

Science.gov (United States)

Fisheries management programs, such as the National Fish Habitat Action Plan (NFHAP), urgently need a nationwide spatial framework and database for health assessment and policy development to protect and improve riverine systems. To meet this need, we developed a spatial framework and database using National Hydrography Dataset Plus (I-.100,000-scale); http://www.horizon-systems.com/nhdplus). This framework uses interconfluence river reaches and their local and network catchments as fundamental spatial river units and a series of ecological and political spatial descriptors as hierarchy structures to allow users to extract or analyze information at spatial scales that they define. This database consists of variables describing channel characteristics, network position/connectivity, climate, elevation, gradient, and size. It contains a series of catchment-natural and human-induced factors that are known to influence river characteristics. Our framework and database assembles all river reaches and their descriptors in one place for the first time for the conterminous United States. This framework and database provides users with the capability of adding data, conducting analyses, developing management scenarios and regulation, and tracking management progresses at a variety of spatial scales. This database provides the essential data needs for achieving the objectives of NFHAP and other management programs. The downloadable beta version database is available at http://ec2-184-73-40-15.compute-1.amazonaws.com/nfhap/main/.

Wang, L.; Infante, D.; Esselman, P.; Cooper, A.; Wu, D.; Taylor, W.; Beard, D.; Whelan, G.; Ostroff, A.

2011-01-01

344

Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment.  

Science.gov (United States)

This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05-3.01 mg kg(-1) wet weight (w. wt) and 8.41-22.76 mg kg(-1) dry weight (d. wt), respectively. In addition, the As content was positively correlated (p aquaculture ponds were selected for investigation: (1) omnivorous food chain (zooplankton, grass carp and bighead carp) and (2) predatory food chain (zooplankton, mud carp and mandarin fish). Significant linear relationships were obtained between log As and ? (15)N. The slope of the regression (-0.066 and -0.078) of the log transformed As concentrations and ? (15)N values, as biomagnifications power, indicated there was no magnification or diminution of As from lower trophic levels (zooplankton) to fish in the aquaculture ponds. Consumption of largemouth bass, northern snakehead and bighead carp might impose health risks of Hong Kong residents consuming these fish to the local population, due to the fact that its cancer risk (CR) value exceeded the upper limit of the acceptable risk levels (10(-4)) stipulated by the USEPA. PMID:23247527

Cheng, Zhang; Chen, Kun-Ci; Li, Kai-Bin; Nie, Xiang-Ping; Wu, Sheng Chun; Wong, Chris Kong-Chu; Wong, Ming-Hung

2013-07-01

345

Quantitative assessment of accumulation of radionuclides in fish organism in dependence on water temperature  

International Nuclear Information System (INIS)

Eperimentally studied are the changes of levels of several indices of radionuclide metabolism in fishes in dependence on water temperature at its absorption directly from water and at introduction into the digestive tract. Presented are the coefficients of radionuclide storage by the fish tissues in the dependence on temperature (scales and fins, gills, head, intestines, skin, muscles, axial skeleton) and the coefficients of radionuclide retention in the whole fish. It is shown that the connection between the coefficient of radionuclide storage in the fish organism and water temperature is described by the logarithmic dependence. At the systematic entering of radionuclides into the digestive tract the retention coefficient of them in the organism expressed in the form of the ratio of residual quantity in the fish to the quantity in day dose is constant

346

Augmented Fish Health Monitoring for Washington Department of Wildlife, 1988 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

The augmented fish health monitoring project is funded by the Bonneville Power Administration with the mandate to collect fish health data on anadromous fish stocks of the Columbia River Basin in a standardized manner. The project began in 1986 and the data reported here was collected in the third year. This segment of the project was carried out by the Washington Department of Wildlife and summarizes fish health findings at anadromous game hatcheries in Washington State operated by the BPA. Information gathered to date has provided impetus to alter facility design and management practices for improved fish health through prevention. Treatment efficacy can be better assessed due to the monthly monitoring of fish stocks and insight is being gained into disease prevention and control. The ultimate goal, of course, is to improve fish health for better survival in the wild. Tagged returns at index hatcheries within this project area will indicate the impact of improving fish health on providing greater adult returns as well as an improved product for the fishery. 2 refs., 3 figs., 15 tabs.

Gearheard, Jim

1988-10-01

347

Can fish gill anomalies be used to assess water quality in freshwater neotropical systems?  

Science.gov (United States)

Gill anomalies in two fish species (Geophagus brasiliensis and Astyanax bimaculatus) were compared among three freshwater systems with different water quality: one eutrophic river, one eutrophic reservoir, and one oligotrophic reservoir. The raised hypotheses are that reservoirs with low water quality (eutrophic) have fish with more gills anomalies compared with reservoirs with high water quality (oligotrophic), and that the more stable environmental conditions of eutrophic rivers have fish with better healthy conditions than eutrophic reservoirs that have lesser stable environmental conditions. Gills of 36 adult individuals of G. brasiliensis and 23 of A. bimaculatus collected during the winter 2008 and winter 2009 were examined, and the proportions of occurrence of nine histological alterations were compared for the two species among the three systems using a binomial t test for independent samples. Histological changes in fish gills that are reversible and unspecific, such as epithelial lifting, interstitial edema, leukocyte infiltration, hyperplasia of the epithelial cells, lamellar fusion, and vasodilatation were common in both fish species in the three systems. However, lamellar aneurism, which is a more serious and often irreversible anomaly, and lamellar blood congestion occurred only in fish from the two reservoir