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1

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

2

Annual trends in catchability and fish stock assessments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 XS...

Marchal, P.; Ulrich, C.; Korsbrekke, K.; Pastoors, M. A.; Rackham, B.

2003-01-01

3

Stocking fish  

…fish: A GUIDE FOR fishery owners AND anglers For more copies of this booklet please contact: National Coarse Fisheries Centre Environment Agency Arthur Drive Hoo Farm Industrial Estate Worcester Road Kidderminster Worcs DY11 7RA Tel: 01562 68975 Fax: 01562 69477 1 Stocking fish: a guide for fishery…

4

Report of the Workshop on Methods of Fish Stock Assessment [Reykjavik, 6 -12 July, 1988  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Introduction: For the purposes of this report, the meaning of "fish stock assessment" is restricted to any procedure by which the historical and current state of a fish stock is estimated. This definition includes no reference to prediction of possible future states of the stock and no attention was given to prediction in the course of this meeting. It should also be noted that, in real-life assessments, recruitment estimates for the most recent data years are often obtained by tech...

ICES

1988-01-01

5

Understanding environmental control on fish stocks and progress toward their inclusion in fish stock assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The need to understand the impact of the environment on the fluctuations in fisheries yield in the Northeast Atlantic was a major motivation for the creation of ICES. From the very beginning, two main research tasks were talen on: l) the establishment of relationships between the distribution and behaviour of fish and environmental characteristics for the purpose of real-time and short-term predictions and advice about where and when the fishing fleets could increase their catches, and 2) the...

Nakken, Odd

2002-01-01

6

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 â??semi-manual distributed datawarehouseâ? 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 â?? it is in organisation, coordination and trust. This challenge has been addressed by FishFrame - a web-based datawarehouse application. The â??bottom-upâ? 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

7

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.

8

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

9

Species interaction in assessment of fish stocks with special application to the North Sea  

DEFF Research Database (Denmark)

A multispecies Virtual Population Analysis model is presented in which natural mortality is split into a variable mortality due to predation and a constant mortality due to other causes. Predation is calculated within the model from the food selection of the predators, their yearly food intake and the average stock sizes. The model is tested on a set of data from the North Sea. The results indicate that predation is very important. On average the total biomass of fish dead due to predation amounts to 1.6 times that removed by the fishery. Furthermore the introduction of predation mortality changes the exploitation pattern calculated by traditional VPA.

Gislason, Henrik; Helgason, T.

1985-01-01

10

The Catch-Survey Analysis (CSA) method of fish stock assessment: an evaluation using simulated data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Catch-Survey Analysis (CSA) method of assessment aims at estimating stock abundance from relative indices by filtering measurement error in the latter through a simple two-stage population dynamics model. The method is not widely used and the associated literature is still limited. The objective of this work is to improve current understanding of the properties of the method, using data generated from a known fully age-structured population. A sensitivity analysis confirms that CSA is cap...

2003-01-01

11

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

2013-01-01

12

Quantifying relative fishing impact on fish populations based on spatio-temporal overlap of fishing effort and stock density  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Evaluations of the effects of management measures on fish populations are usually based on the analyses of population dynamics and estimates of fishing mortality from stock assessments. However, this approach may not be applicable in all cases, in particular for data-limited stocks, which may suffer from uncertain catch information and consequently lack reliable estimates of fishing mortality. In this study we develop an approach to obtain proxies for changes in fishing mortality based on eff...

Vinther, Morten; Eero, Margit

2013-01-01

13

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

14

The Assessment of the Western Mackerel Stock  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mackerel fishery is one of the most important components of the Irish fishing industry. The annual Irish quota is based on the scientific assessments of the size of the spawning stock. These assessments are based on the mackerel egg surveys which are carried out every three years and on the age composition of the total catches. The assessments have indicated that the stock in recent years has declined substantially and is now below 2 million tonnes. Predictions on the development of the s...

Molloy, J.

1996-01-01

15

Intelligent Fish Freshness Assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-sa...

Hamid Gholam Hosseini; Dehan Luo; Guanggui Xu; Hongxiu Liu; Deena Benjamin

2008-01-01

16

Fish otoliths analysis by PIXE: application to stock discrimination  

Energy Technology Data Exchange (ETDEWEB)

Fish otoliths are continuously deposited from fish birth to its death along with encoding environmental information. In order to decode the information, PIXE was adopted as trace elemental analysis of the otoliths. Strontium to calcium concentration ratios of red sea bream otoliths varied among rearing stations. The Sr/Ca ratios of Lake Biwa catfishes also varied between male and female and among fishing grounds. The PIXE analysis was applied to the fish stock discrimination. (author)

Arai, Nobuaki; Takai, Noriyuki; Sakamoto, Wataru [Kyoto Univ. (Japan). Faculty of Agriculture; Yoshida, Koji; Maeda, Kuniko

1996-12-31

17

Why non-native fish pose a threat to our fish stocks  

Why non-native fish pose a threat to our fish stocks The introduction of non-native fish species to our waters is not a new phenomenon. As far back as Roman times, fish such as common carp were moved from their native range for food. The formation of ??The Society for the Acclimatisation of Animals…

18

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

19

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

20

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

 
 
 
 
21

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

22

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.

Collie, J.S.; Gislason, Henrik

2001-01-01

23

Single and multispecies reference points for Baltic fish stocks  

DEFF Research Database (Denmark)

Single and multispecies models are used to examine the effect of species interaction on biological reference points for cod, herring, and sprat in the Baltic. The results demonstrate that reference points are different in single and multispecies contexts. Reference points for fishing mortality based on single-species yield and SSB calculations are difficult to use when natural mortality depends on the absolute abundance of the predators and their alternative prey. Reference points based on maximizing total yield from the system may lead to impractical results when species interact. Multispecies predictions suggest that the cod stock in the Baltic should be reduced to a very low level of biomass in order to benefit from the higher productivity of herring and sprat, its major prey. Such a result stresses the need for incorporating socio-economic considerations in the definition of target reference points. Management advice based on biomass reference points will also differ. In the single species situation the combinations of cod and pelagic fishing effort for which the equilibrium spawning- stock biomass of the three species is above the biomass reference points forms a rectangular area. When biological interaction is taken into account the limits of this area becomes curved. Reference limits for forage fish cannot be defined without considering changes in the biomass of their natural predators. Likewise, reference limits for predators cannot be defined without considering changes in the biomass of their prey. (C) 1999 International Council for the Exploration of the Sea.

Gislason, Henrik

1999-01-01

24

Why non-native fish pose a threat to our fish stocks  

…the zander Sander lucioperca amongst others. Some species, such as the wels catfish have been introduced to fisheries to provide an additional attraction and draw for anglers. Providing these fish are legally stocked into the right waters, they cause no harm to the wider environment. It is when non…

25

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

26

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)

1988-01-01

27

Conservation of Atlantic salmon by supplementary stocking of juvenile fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wild salmon stocks in the northern Baltic rivers became endangered in the second half of the 20th century, mainly due to recruitment overfishing. As a result, supplementary stocking was widely practised, and supplementation of the Tornionjoki salmon stock took place over a 25 year period until 2002. The stock has been closely monitored by electrofishing, smolt trapping, mark-recapture studies, catch samples and catch surveys. Background information on hatchery-reared stocked juveniles was als...

Romakkaniemi, Atso

2008-01-01

28

Assessing the effects of a chronic stressor, stocking density, on welfare indicators of juvenile African catfish, Clarias gariepinus Burchell.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fish welfare is an area of increasing interest and stocking densities used in commercial aquaculture have been highlighted as a subject of specific welfare concern. The present study assessed how stocking density affects growth performance (final body weight, SGR, FCR), physiological (plasma cortisol, glucose, lactate) and behavioural (swimming activity, stereotypes, escapes, aggression, airbreathing) responses of farmed African catfish (Clarias gariepinus). We stocked African catfish (10g) i...

Nieuwegiessen, P. G.; Boerlage, A. S.; Verreth, J. A. J.; Schrama, J. W.

2008-01-01

29

Fish wars on the high seas :a straddling stock competition model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The post World War II era saw the development of powerful self-contained fishing fleets, so-called distant-water fleets (DWFs), which roamed the worlds oceans, seeking out rich harvesting targets wherever they might be found. These fleets practiced pulse fishing, harvesting a given fish stock intensively, then moving on, leaving a depleted fishery which might require many years to recover. With the creation in the 1980s of coastal states' extended economic zones ((EEZs), to manage fisheries ...

Mckelvey, Robert W.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar

2001-01-01

30

Fish wars on the high seas :a straddling stock competition model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The post World War II era saw the development of powerful self-contained fishing fleets, so-called distant-water fleets (DWFs), which roamed the world’s oceans, seeking out rich harvesting targets wherever they might be found. These fleets practiced pulse fishing, harvesting a given fish stock intensively, then moving on, leaving a depleted fishery which might require many years to recover. With the creation in the 1980s of coastal states’ extended economic zones (EEZs), to manage fisheri...

Mckelvey, Robert W.; Sandal, Leif Kristoffer; Steinshamn, Stein Ivar

2001-01-01

31

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 T...

Banu, A. N. H.; Khan, M. H.

2004-01-01

32

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

33

Ageing of Fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to assess the state of any fish stock it is vital that the age structure of that stock is known. The age profile of a stock gives an indication on how healthy the stock is. If there is a broad range of ages present, then the stock would appear to be in good shape. If there are no young fish, then recruitment (spawning) may have failed and there will be problems in the future. If there are no old fish in the stock, then there may be overfishing of the stock. Age data give a good insig...

Institute, Marine

2006-01-01

34

Guide to Fisheries Science and Stock Assessments.  

Science.gov (United States)

Marine fisheries management is a complex process incorporating fisheries biology and stock status information, food web and predator/prey relationships, habitat needs, socioeconomic needs of recreational and commercial fishermen, and law enforcement issue...

J. Carmichael P. Kilduff R. Latour

2009-01-01

35

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

36

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

37

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

38

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

39

Reared fish, farmed escapees and wild fish stocks— a triangle of pathogen transmission of concern to Mediterranean aquaculture management  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although aquaculture in the Mediterranean is a relatively young industry, finfish diseases have been reported to cause considerable problems and mortalities among the farmed stocks. In general, the farming activity and the open design of Mediterranean aquaculture systems allow the transmission of infectious pathogens within and among farm facilities. Fish health and biosecurity programmes at farms have focused on the most obvious pathways for transmission of pathogens, i.e. through transport ...

Arechavala Lo?pez, Pablo; Sa?nchez Jerez, Pablo; Bayle Sempere, Just T.; Uglem, Ingebrigt; Mladineo, Ivona

2013-01-01

40

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

 
 
 
 
41

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

42

Climate, competition and the management of shared fish stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Long-term climate regime shifts have profound impacts on ocean temperature and circulation patterns, and on the dynamics of fish populations. Climate regime shifts can disrupt otherwise satisfactory international management agreements. Game theory provides a perspective on the difficulty of maintaining cooperative management of shared fishery resources in the face of environmental changes. This paper draws upon two case studies -- Pacific salmon and Norwegian spring-spawning herring -- to dem...

Miller, Kathleen; Munro, Gordon R.; Bjørndal, Trond

2004-01-01

43

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

44

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; Ruzzante, D.E.

2001-01-01

45

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

46

Why non-native fish pose a threat to our fish stocks  

…Sphaerothecum destruens, in the highly invasive fish, the topmouth gudgeon, Pseudorasbora parva, highlights this risk. In the United States, this pathogen has prevented other species form spawning and there are concerns as to the effects that it may have on our native fish species. At our National Fisheries…

47

Why non-native fish pose a threat to our fish stocks  

…rosette agent, Sphaerothecum destruens, in the highly invasive fish, the topmouth gudgeon, Pseudorasbora parva, highlights this risk. In the United States, this pathogen has prevented other species form spawning and there are concerns as to the effects that it may have on our native fish species. At…

48

Why non-native fish pose a threat to our fish stocks  

…population had on a small stillwater fishery, where no young native fish were found in fishery surveys. Also, the growth of roach and carp was severely limited by the competition from the topmouth gudgeon. Once introduced, eradication of this species is both costly and extremely difficult. Non-native fish introductions…

49

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

50

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

51

Population level impacts of cooling water withdrawals on harvested fish stocks.  

Science.gov (United States)

Trillions of gallons are withdrawn every year from U.S. rivers, estuaries, lakes, and coastal waters to cool the turbines of power plants and other equipment in manufacturing facilities. In the process, large numbers of aquatic organisms die from entrainment into the plant or impingement against the outer portion of the intake structure. In this paper, we develop a generalized age-structured population model with density dependent survival of sub-adult age classes, and we use the model to perform a screening analysis of the effects of entrainment and impingement for 15 harvested fish stocks off the California and Atlantic coasts. Stock sizes are estimated to be depressed by entrainment and impingement by less than 1% in 10 of the 15 cases considered, between 1 and 3% in two cases, and between 20 and 80% in three cases. A variety of sensitivity analyses are conducted to evaluate the influence of several sources of model and parameter uncertainties. PMID:17438750

Newbold, Stephen C; Iovanna, Rich

2007-04-01

52

Annual Coded Wire Tag Program; Oregon Stock Assessment, 2000 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's Annual Stock Assessment - Coded Wire Tag Program (ODFW) Project. Tule stock fall chinook were caught primarily in British Columbia and Washington ocean, and Columbia Basin fisheries. Up-river bright stock fall chinook contributed primarily to Alaska and British Columbia ocean commercial, Columbia Basin gillnet and freshwater sport fisheries. Contribution of Rogue stock fall chinook released in the lower Columbia River occurred primarily in Oregon ocean commercial, Columbia Basin gillnet and freshwater sport fisheries. Willamette stock spring chinook contributed primarily to Alaska and British Columbia ocean, and Columbia Basin sport fisheries. Willamette stock spring chinook released by CEDC contributed to similar ocean fisheries, but had much higher catch in Columbia Basin gillnet fisheries than the same stocks released in the Willamette Basin. Up-river stocks of spring chinook contributed almost exclusively to Columbia Basin fisheries. The up-river stocks of Columbia River summer steelhead contributed almost exclusively to the Columbia Basin gillnet and freshwater sport fisheries. Coho ocean fisheries from Washington to California were closed or very limited from 1994 through 1999 (1991 through 1996 broods). This has resulted in a lower percent of catch in Washington, Oregon and California ocean fisheries, and a higher percent of catch in Alaska and British Columbia ocean and Columbia Basin freshwater fisheries. Coho stocks released by ODFW below Bonneville Dam were caught mainly in Oregon, Washington, and British Columbia ocean, Columbia Gillnet and freshwater sport fisheries. Coho stocks released in the Klaskanine River and Youngs Bay area had similar ocean catch distributions, but a much higher percent catch in gillnet fisheries than the other coho releases. Ocean catch distribution of coho stocks released above Bonneville Dam was similar to the other coho groups. However, they had a higher percent catch in gillnet fisheries above Bonneville Dam than coho released below the dam. Survival rates of salmon and steelhead are influenced, not only by factors in the hatchery (disease, density, diet, size and time of release) but also by environmental factors in the river and ocean. These environmental factors are influenced by large scale oceanic and weather patterns such as El Nino. Changes in rearing conditions in the hatchery do impact survival, however, these can be offset by impacts caused by environmental factors. Coho salmon released in the Columbia River generally experience better survival rates when released later in the spring. However, for the 1990 brood year June releases of Columbia River coho had much lower survival than May releases, for all ODFW hatcheries. In general survival of ODFW Columbia River hatchery coho has declined to low levels in recent years. Preliminary results from the evaluation of Visual Implant Elastomer (VIE) tags showed tagging rate and pre-release tag retention improved from the first to second years of tagging. Tagging rate remained identical from 1999 to 2000 while pre-release tag retention dropped to 95%. Returning jack and adult salmon were sampled for CWT and VIE tags in the fall of 2000. Of 606 adults recovered at Sandy Fish Hatchery in 2000, only 1 or 0.2%, retained their VIE tag. Of 36 jacks recovered in 2000, 13 or 36.1% retained their VIE tag.

Lewis, Mark; Mallette, Christine; Murray, William

2002-03-01

53

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ba...

Lin Sun; Hongjun Xiao; Shouju Li; Dequan Yang

2009-01-01

54

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

55

Stocking of Offsite Waters for Hungry Horse Dam Mitigation; Creston National Fish Hatchery, 2001-2002 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

Mitigation Objective 1: Produce Native Westslope Cutthroat Trout at Creston NFH--Task: Acquire eggs and rear up to 100,000 Westslope Cutthroat trout annually for offsite mitigation stocking. Accomplishments: A total of 150,000 westslope cutthroat eggs (M012 strain) were acquired from the State of Montana Washoe Park State Fish Hatchery in July 2001 for this objective. Another 120,000 westslope cutthroat eggs were taken from feral fish at Rogers Lake in May of 2001 by the Creston Hatchery crew. The fish were reared using approved fish culture techniques as defined in the U.S. Department of the Interior Fish Hatchery Management guidelines. Post release survival and angler success is monitored annually by Montana Fish Wildlife and Parks (MFWP) and the Confederated Salish and Kootenai Tribe (CSKT). Stocking numbers and locations may vary yearly based on results of biological monitoring. Mitigation Objective 2: Produce Rainbow Trout at Creston NFH--Task: Acquire and rear up to 100,000 Rainbow trout annually for offsite mitigation in closed basin waters. Accomplishments: A total of 50,500 rainbow trout eggs (Arlee strain) were acquired from the State of Montana Arlee State Fish Hatchery in December 2001 for this objective. The fish were reared using approved fish culture techniques as defined in the U.S. Department of the Interior Fish Hatchery Management guidelines. Arlee rainbow trout are being used for this objective because the stocking locations are terminal basin reservoirs and habitat conditions and returns to creel are unsuitable for native cutthroat. Post release survival and angler success is monitored annually by the Confederated Salish and Kootenai Tribe (CSKT). Stocking numbers and locations may vary yearly based on results of biological monitoring.

Maskill, Mark (US Fish and Wildlife Service, Creston National Fish Hatchery, Kalispell, MT)

2003-03-01

56

Why non-native fish pose a threat to our fish stocks  

…locations throughout England and Wales.  Primarily found here in stilwaters, the topmouth gudgeon can reproduce rapidly with numbers in excess of 65 individuals per square metre.  At these levels, competition with the native fish species for food and spawning habitat is a major concern. A recent study…

57

Why non-native fish pose a threat to our fish stocks  

…that they can cause environmental damage. In addition to non-native fish species that have been introduced to boost angling, there are others, now present in the wild, that were originally from the aquarium trade. Such introductions are illegal and these are the most likely to pose a threat to our…

58

Why non-native fish pose a threat to our fish stocks  

…found here in stilwaters, the topmouth gudgeon can reproduce rapidly with numbers in excess of 65 individuals per square metre.  At these levels, competition with the native fish species for food and spawning habitat is a major concern. A recent study showed the impacts such a population had on a small…

59

Why non-native fish pose a threat to our fish stocks  

…for food and spawning habitat is a major concern. A recent study showed the impacts such a population had on a small stillwater fishery, where no young native fish were found in fishery surveys. Also, the growth of roach and carp was severely limited by the competition from the topmouth gudgeon. Once…

60

Stocking of Offsite Waters for Hungry Horse Dam Mitigation; Creston National Fish Hatchery, 2002-2003 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

Mitigation Objective 1: Produce Native Westslope Cutthroat Trout at Creston NFH--Task: Acquire eggs and rear up to 100,000 Westslope Cutthroat trout annually for offsite mitigation stocking. Accomplishments: A total of 141,000 westslope cutthroat eggs (M012 strain) was acquired from the State of Montana Washoe Park State Fish Hatchery in May 2002 for this objective. We also received an additional 22,000 westslope cutthroat eggs, MO12 strain naturalized, from feral fish at Rogers Lake, Flathead County, Montana. The fish were reared using approved fish culture techniques as defined in the U.S. Fish and Wildlife Service, Fish Hatchery Management guidelines. Survival from the swim up fry stage to stocking was 95.6%. We achieved a 0.80 feed conversion this year on a new diet, Skretting ''Nutra Plus''. Post release survival and angler success is monitored annually by Montana Fish Wildlife and Parks (MFWP) and the Confederated Salish and Kootenai Tribe (CSKT). Stocking numbers and locations vary yearly based on results of biological monitoring and adaptive management. Mitigation Objective 2: Produce Rainbow Trout at Creston NFH--Task: Acquire and rear up to 100,000 Rainbow trout annually for offsite mitigation in closed basin waters. Accomplishments: A total of 54,000 rainbow trout eggs (Arlee strain) was acquired from the Ennis National Fish Hatchery in December 2002 for this objective. The fish were reared using approved fish culture techniques as defined in the U.S. Fish and Wildlife Service, Fish Hatchery Management guidelines. Survival from the swim up fry stage to stocking was 99.9%. We achieved a 0.79 feed conversion this year on a new diet, Skretting ''Nutra Plus''. Arlee rainbow trout are being used for this objective because the stocking locations are terminal basin reservoirs and habitat conditions and returns to the creel are unsuitable for native cutthroat. Post release survival and angler success is monitored annually by the Confederated Salish and Kootenai Tribe (CSKT). Stocking numbers and locations vary yearly based on results of biological monitoring and adaptive management.

US Fish and Wildlife Service Staff, (US Fish and Wildlife Service, Creston National Fish Hatchery, Kalispell, MT)

2004-02-01

 
 
 
 
61

Preliminary spatially disaggregated stock assessment of northern hake, a widely distributed stock of the north-east Atlantic  

Digital Repository Infrastructure Vision for European Research (DRIVER)

European hake (Merluccius merluccius) is widely distributed over the north-east Atlantic shelf, from Norway to Mauritania. Despite its large distribution (covering ICES Division IIIa, Subareas IV, VI and VII and Divisions VIIIa,b,d, from Norway to the Bay of Biscay) and a complex population structure, the so-called northern stock of hake is currently assessed as a single unit, using a spatially aggregated implementation of the Stock Synthesis assessment model. In this study, a preliminary spa...

2012-01-01

62

The reliability of fishing statistics as a source for catches and fish stocks in antiquity  

DEFF Research Database (Denmark)

In 1985, T.W. Gallant published an influential essay on the potential productivity of fishing in the ancient world. He concluded that: â?the role of fishing in the diet and economy would have been, on the whole, subordinate and supplementaryâ?¦â? His methodological approach was original in using modern fishery data to estimate the productivity of ancient fisheries. Unfortunately his work suffered from several severe misunderstandings about ecosystems, the nature of a fishery and its biological interaction with its environment. The purpose of this paper is to discuss the statistical background for Gallantâ??s conclusions about fishery and the usefulness of modern catch data for historical fishery research. In order to do so, the author adopts the viewpoint of marine-environmental history, with some reference to other authorsâ?? work on ancient fisheries.

Jacobsen, A. Lif Lund

2005-01-01

63

77 FR 47043 - Draft 2012 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...non-strategic'' stocks). Strategic stocks included: Hawaiian monk seal, Southern Resident killer whale, Hawaii Insular false...abundance estimates are available for eight stocks: Hawaiian monk seal, Long-beaked common dolphin, Southern Resident...

2012-08-07

64

Gulf of Mexico Pink Shrimp Assessment Modeling Update from a Static VPA to an Integrated Assessment Model Stock Synthesis.  

Science.gov (United States)

The Gulf of Mexico (GOM) pink shrimp stocks were deemed undergoing overfishing in 2008 at the conclusion of the 2007 fishing season (National Marine Fisheries Service 2009). This designation was made because the SEFSC Galveston Laboratory's Virtual Popula...

J. M. Nance R. A. Hart

2010-01-01

65

Effect of dietary supplementation with vitamin E and stocking density on macrophage recruitment and giant cell formation in the teleost fish, Piaractus mesopotamicus.  

Science.gov (United States)

The effect of dietary supplementation with 0, 100 and 450 mg of vitamin E (DL-alpha tocopheryl acetate)/kg of a dry diet on the kinetics of macrophage recruitment and giant cell formation in the pacu, maintained at different stocking densities (5 kg/m(3) and 20 kg/m(3)), was investigated by insertion of round glass coverslips into the subcutaneous connective tissue. After a feeding period of 18 weeks, the coverslips were implanted and later removed for examination at 2, 7 and 15 days post-implantation. Fish fed diets supplemented with 450 mg of vitamin E showed an increase (P<0.05) in the accumulation of macrophages, foreign body giant cells and Langhans type cells. The kinetics of macrophage recruitment and giant cell formation on the glass coverslips appeared to be strongly influenced by vitamin E supplementation, since fish fed a basal diet and held at high stocking densities showed low numbers of adhering cells on the coverslips, and high concentrations of plasma corticosteroids. On the other hand, fish given a diet supplemented with 450 mg of vitamin E did not show a similar difference in plasma cortisol concentrations related to stocking density. The effect of cortisol concentrations on carbohydrate metabolism, analysed by assessment of plasma glycaemia, was not clear. Blood glucose concentrations did not vary substantially with the different treatments examined. These results suggest that vitamin E may contribute to the efficiency of the fish's inflammatory response by increasing macrophage recruitment and giant cell formation in the foreign body granulomatous reaction. Vitamin E appeared to act on the stress response of pacus by preventing a stress-related immunosuppression. PMID:16033696

Belo, M A A; Schalch, S H C; Moraes, F R; Soares, V E; Otoboni, A M M B; Moraes, J E R

2005-01-01

66

Mekong River fish conservation zones in southern Laos: assessing effectiveness using local ecological knowledge.  

Science.gov (United States)

Small-scale fisheries are important in Laos, where rural people heavily depend upon Mekong River and tributary fish stocks for their livelihoods. Increasing pressures from human exploitation and habitat disturbance, however, have raised serious concerns about the potential depletion of various species. This has led to the establishment of large numbers of Fish Conservation Zones (FCZs) or "no-take" fish sanctuaries in southern Laos based on a "community-based fisheries co-management" framework. This study uses the local ecological knowledge (LEK) of fishers to assess the effectiveness of village-managed FCZs in enhancing fish stocks in the mainstream Mekong River in Khong District, Champasak Province. Focus group interviews about species that are believed to have benefited from different FCZs are compared with parameters such as FCZ area, age, depth, localized gradient, water velocity, and the presence of wetland forests nearby. The results suggest that no one aspect is likely to account for variations in fish stocks; rather, it is the interaction between numerous factors that has the largest impact. Secondly, the results indicate that microhabitat diversity and protection are critical for maintaining and enhancing Mekong fisheries. Deep-water pools are particularly important as dry season refuges for many fish species, and FCZ depth may be the single most important environmental factor affecting the success of FCZs in the Mekong River. FCZs have the most potential to benefit relatively sedentary species, but may also benefit highly migratory species, given the right conditions. This study shows that integrated approaches to stock assessment that employ LEK and scientific fisheries management have considerable potential for improving Mekong capture-fisheries management. PMID:16132441

Baird, Ian G; Flaherty, Mark S; Baird, Ian G

2005-09-01

67

Annual Coded Wire Tag Program; Oregon Stock Assessment, Annual Report 2002.  

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 2002 contract period: Objective 1 - Over 1 million juvenile salmon were coded-wire by this program (Table 1). This accounted for about 20% of the fish ODFW coded-wire tagged in 2002 for release in the Columbia Basin; Objective 2 - ODFW recovered and processed over 50,000 snouts collected from coded-wire tagged fish (Table 2); Objective 3 - The survival data summarized below includes results for coded-wire groups funded by this program as well as coded-wire groups funded from other sources; Objective 4 - The last returns of experimental groups of coho marked with VIE tags occurred in 2002 at Sandy Hatchery. This sampling showed that 26 of 67 jack coho and 1 of 2,223 adult coho VIE marked as juveniles retained the VIE mark as adults.

Lewis, Mark; Mallette, Christine; Murray, William

2003-03-01

68

76 FR 52940 - Draft 2011 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...stocks, including four ``strategic'' stocks (Hawaiian monk seal, Southern Resident killer whale, Hawaii Insular false...California sea lion, California harbor seal, Hawaiian monk seal, and Southern Resident killer whale. The abundance...

2011-08-24

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

The determination of a complex criterion for assessing the performance of traction rolling stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For assessing the quality of rolling stocks, the research was made into the operational expenses aimed to derive their relation with the time of rolling stock operation which could be used as a basis of the above generalized complex criterion. In this way a dimensionless composite index with the value not exceeding one was obtained for assessing the locomotive performance. If this index is more than one, the rolling stock should be written off as inefficient and obsolete equipment.

2004-01-01

71

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.

72

The effects of EU fisheries partnership agreements on fish stocks and fishermen: The case of Cape Verde  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The viewpoints of 30 Cape Verdean fishermen are used together with an analysis of the state of tuna stocks in the Atlantic Ocean to question the EU's claim that their fleet only targets surplus species. Additionally, local marine catches of the artisanal and semi-industrial fleet are evaluated and the importance of the fisheries sector for the inhabitants of Cape Verde is shown. It is argued that even though the EU condemns illegal, unreported and unregulated fishing (IUU); their approach to ...

2012-01-01

73

Fish Catch Assessment of Maljhee-Kangsa Floodplain in Bangladesh  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 (...

Ahmed, N.; Rahman, M. M.

2005-01-01

74

Fish Stock Endogeneity in a Harvest Function: ‘El Niño’ Effects on the Chilean Jack Mackerel Fishery  

Directory of Open Access Journals (Sweden)

Full Text Available There are several examples of pelagic fisheries that have experienced fishing collapse when facing downward abundance cycles. Improving understanding about pelagic catch’s stock dependence can help avoid new cases of fishing collapse. This paper analyses the possible endogeneity of the fish stock variable in a pelagic fishery harvest function. The harvest function is estimated using panel data and ‘El Niño’ episodes as instrumental variable for the Chilean jack mackerel biomass. This strategy produces consistent estimates of the fish biomass coefficient. The paper makes two contributions. First, it corrects for endogeneity of the fish stock variable, an issue often underestimated in empirical fishery economics. Secondly, it shows that ‘El Niño’ episodes have negative effects on the Chilean jack mackerel biomass.

Sebastián Vergara

2007-03-01

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

1988-01-01

76

Growing stock-based assessment of the carbon stock in the Belgian forest biomass  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Belgian forests covered 693 181 ha in 2000, representing 22.7% of the total land area. As no biomass or carbon stock data are included in the Flemish and Walloon regional forest inventories, species-specific wood densities, biomass expansion factors s.s. and carbon content values were critically selected from the literature. Based on these conversion and expansion factors, and on data from the forest inventories, the total C-stock in the living biomass of productive Belgian forests was asses...

Vande Walle, Inge; Camp, Nancy; Perrin, Dominique; Raoul Lemeur,; Verheyen, Kris; Wesemael, Bas; Laitat, Eric

2005-01-01

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

Fréon, Pierre; Yáñez R, Eleuterio.

78

The Application of 'Rotenone' for the Extermination of the Indigenous Fish Stock in Waters Where Intensive Fish Farming Is To Be Introduced (Primena 'Rotenona' za Iskorenjivanje Riblje Faune u Vodama Gde Se Uv odi Intensivno Gazdovanje).  

Science.gov (United States)

Experimental findings on the use of 'Rotenone' lead to the following conclusions: Good results with rotenone for liquidating the indigenous fish stock in standing waters were confirmed in an experiment on the Opovacki Dunavac. Though the water temperature...

I. Mihajlovic V. Rajevski

1973-01-01

79

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

80

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

 
 
 
 
81

77 FR 29969 - Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...the SAR was drafted in 2010. The Main Hawaiian Island monk seal population is estimated to be growing robustly despite...underlying assumptions in calculating PBR between the Hawaiian monk seal and Hawaii insular stock of false killer whale. The...

2012-05-21

82

78 FR 66681 - Draft 2013 Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...Cuvier's beaked whale, CA/OR/WA, and mesoplodont beaked whales, CA/OR/WA. Strategic stocks included: Monk seal, killer whale (Eastern North Pacific Southern Resident), Mesoplodont beaked whales (CA/OR/WA), Cuvier's...

2013-11-06

83

76 FR 34054 - Marine Mammal Stock Assessment Reports  

Science.gov (United States)

...states the stock's dynamics do not conform to the underlying model for calculating PBR such that PBR for the Hawaiian monk seal is undetermined. This seems a more appropriate and prudent approach, and HSUS believes that the Alaska region...

2011-06-10

84

Mussel (Mytilus edulis) culture management along the Normandy coastline (France) : stock assessment and growth monitoring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Normandy region is presently a leading shellfish rearing area in France yielding 35,000 metric tons of oysters C. gigas and Il,000 metric tons of mussels M. edulis on a yearly basis. Preliminary studies were initiated in 1989, 1991 and 1992 to develop the sampling strategy for cultured mussel stock assessment. Comprehensive mussel stock assessment and concomitant growth monitoring were carried out in 1993 to study mussel population and optimize overall s1l1ellfish culture management. ...

Goulletquer, Philippe; Joly, Jean-pierre; Le Gagneur, Eric; Ruelle, Francois

1994-01-01

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

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.

87

Environmental life cycle assessments of fish food products with emphasis on the fish catch process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sustainable development embraces economics, society and nature and is the global context for this PhD-thesis. Modern fishery is dependent on fossil fuels, which use is the antithesis of sustainable fishery. Environmental degradation is closely related to health aspects, which are increasingly important to consumers and other stakeholders. For the fish food product (FFP), the main focus of prior research has been on threatened stock populations. Less attention has been focused on environmental...

Schau, Erwin Andreas Meissner

2012-01-01

88

Assessing Fishing and Marine Biodiversity Changes Using Fishers' Perceptions: The Spanish Mediterranean and Gulf of Cadiz Case Study  

Science.gov (United States)

Background The expansion of fishing activities has intensively transformed marine ecosystems worldwide. However, available time series do not frequently cover historical periods. Methodology Fishers' perceptions were used to complement data and characterise changes in fishing activity and exploited ecosystems in the Spanish Mediterranean Sea and Gulf of Cadiz. Fishers' interviews were conducted in 27 fishing harbours of the area, and included 64 fishers from ages between 20 to >70 years old to capture the experiences and memories of various generations. Results are discussed in comparison with available independent information using stock assessments and international convention lists. Principal Findings According to fishers, fishing activity substantially evolved in the area with time, expanding towards deeper grounds and towards areas more distant from the coast. The maximum amount of catch ever caught and the weight of the largest species ever captured inversely declined with time. Fishers (70%) cited specific fishing grounds where depletion occurred. They documented ecological changes of marine biodiversity during the last half of the century: 94% reported the decline of commercially important fish and invertebrates and 61% listed species that could have been extirpated, with frequent mentions to cartilaginous fish. Declines and extirpations were in line with available quantitative evaluations from stock assessments and international conventions, and were likely linked to fishing impacts. Conversely, half of interviewed fishers claimed that several species had proliferated, such as cephalopods, jellyfish, and small-sized fish. These changes were likely related to trophic cascades due to fishing and due to climate change effects. The species composition of depletions, local extinctions and proliferations showed differences by region suggesting that regional dynamics are important when analysing biodiversity changes. Conclusions/Significance Using fishers' perceptions, fishing and ecological changes in the study area were documented. The recovery of local ecological knowledge provides valuable information complementing quantitative monitoring and evaluation surveys.

Coll, Marta; Carreras, Marta; Ciercoles, Cristina; Cornax, Maria-Jose; Gorelli, Giulia; Morote, Elvira; Saez, Raquel

2014-01-01

89

An assessment of illegal fishing in Gonarezhou National Park, Zimbabwe  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Illegal fishing is a worldwide problem. In this study we present the first assessment of illegal fishing in Gonarezhou National Park (GNP), Zimbabwe. Information on illegal fishing was gathered from a total of 39 illegal fishers who were arrested within GNP between February and October 2011. Data was collected using semi-structured questionnaires that were administered through interviews. Our results showed that most of the illegal fishing was undertaken by women (n = 32, 82%). Most of the il...

Gandiwa, E.; Zisadza-gandiwa, P.; Mutandwa, M.; Sandram, S.

2012-01-01

90

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.

2012-01-01

91

The fish stocks and fisheries in ICES Sub-Area VI (West of Scotland ...  

identified during Objective 1 for exploited stocks in each of the areas, VIa and ... 3\\) To produce a “Fisheries Handbook” for ICES Sub-area VI, summarising the ... In \\addition to the workshop outlined above, project staff attended two other ...

92

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

93

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 f...

2012-01-01

94

Assessing the impact of the ECB's monetary policy on the stock markets: A sectoral view  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper analyzes the response of the European stock markets to the monetary policy shocks by the European Central Bank using the heteroskedasticity based approach of Rigobon (2003). We find that monetary policy tightening has a heterogeneous impact on the Euro Area sectors on the day the monetary policy is publicly announced. Furthermore, we provide statistical evidence against the use of the popular event study approach when assessing the impact of monetary policy shocks on the stock mark...

Kholodilin, Konstantin Arkadievich; Montagnoli, Alberto; Napolitano, Oreste; Siliverstovs, Boriss

2008-01-01

95

Distribution of Anisakis larvae, identified by genetic markers, and their use for stock characterization of demersal and pelagic fish from European waters: an update.  

Science.gov (United States)

In the present paper, recent results obtained on the use of different distributions observed in larval species of Anisakis, genetically identified by means of allozyme markers, for stock characterization of demersal (Merluccius merluccius), small (Trachurus trachurus) and large pelagic (Xiphias gladius) finfish species in European waters, are reviewed and discussed. Several species of Anisakis were identified in the three fish hosts: A. simplex (s.s.), A. physeteris, A. typica, A. ziphidarum, A. pegreffii, A. brevispiculata and A. paggiae. Canonical discriminant analysis performed on all the samples of the three fish species collected in areas comprising their geographical range, according to the different species of Anisakis identified, showed distinct fish populations in European waters. In all the three fish hosts, the pattern of distribution of Anisakis larvae allowed discrimination of Mediterranean stocks from Atlantic stocks. In the case of swordfish, the possible existence of a southern Atlantic stock separated from a northern one is also suggested. Congruence and discordance with the population genetic data inferred from allozyme markers on the same samples of the three fish species are also discussed. PMID:17578592

Mattiucci, S; Abaunza, P; Damiano, S; Garcia, A; Santos, M N; Nascetti, G

2007-06-01

96

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 mâ??3. Additionally, the influence of the established density limit on physiological indicators of welfare and performance were investigated. At this density of 140 kg mâ??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 mâ??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

97

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

98

Fish passage assessment at the most downstream barrier of the Ebro River (NE Iberian Peninsula)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fish passage at arti?cial barriers is necessary for the conservation of healthy ?sh stocks. The ?rst barrier that migratory ?sh encounter when ascending the Ebro River is the Xerta Weir, where a pool-type ?shway was constructed in 2008. From 2007 to 2010, boat electro?shing surveys were conducted in the Ebro River downstream of the Xerta Weir to assess the potential pool of species that could use the ?shway. Nine native and 12 exotic species were captured, the latter comprising ...

Aparicio, Enric; Pintor, Cristina; Duran, Concha; Carmona Catot, Gerard

2012-01-01

99

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

...ecosystem approach, excess fishing capacity and developing statesrsquo; abilities to develop their fisheries. The outcome also addresses mechanisms for international cooperation; monitoring,...compatibility of conservation and management measures; cooperation for conservation and management; regional fisheries management organizations (RFMOs); collection and provision of information ...Review Conference concluded with recommendations to, inter alia: integrate ecosystem considerations in fisheries management; reduce urgently the worldrsquo;s fishing capacity to levels ...sustainability of fish stocks; strengthening RFMOsrsquo; mandates to implement modern approaches to fisheries; perform RFMO performance reviews; develop a legally- binding instrument ...

100

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)

2013-01-01

 
 
 
 
101

An assessment of the relationship between public real estate markets and stock markets at the local, regional, and global levels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The primary contribution of this study is to assess whether public real estate markets and stock markets are linked at the local, regional, and global levels, and to assess the evolution of their dynamic relationship and gradual integration during the last two decades. For individual pairs of real estate and stock markets, our analysis shows that the current levels of local, regional, and global correlation between real estate and stock markets are time-varying and are, at most, moderate at t...

Liow, Kim Hiang; Schindler, Felix

2011-01-01

102

Towards sustainable fisheries of the Ã?resund cod (Gadus morhua) through sub-stock-specific assessment and management recommendations  

DEFF Research Database (Denmark)

Fisheries management traditionally relies on stock assessments assuming discrete populations within large administrational areas. However, failing to account for sub-stock structuring may result in overestimation of the stocks' true harvest potential and unsustainable exploitation of small stock elements. Atlantic cod (Gadus morhua) frequently occurs in spatially segregated populations, some of which exhibit fine-scaled stock structuring within current management boundaries. Here we use the locally spawning cod stock in the Sound (â??Ã?resundâ?) as a case study, and perform a sub-stock-specific assessment to evaluate biological and economic effects of managing the Sound cod as a separate stock. Our results indicate that reducing exploitation pressure, particularly through technical regulations i.e. increasing gill-net mesh sizes, would not only enhance the stock age distribution, but yield long-term net benefits to the local gill-net fishery. Furthermore, our study emphasizes the need for developing sub-stock-specific management recommendations in order to ensure the maintenance of fisheries resources in general, and the persistence of sub-stock structuring in particular.

Lindegren, Martin; Waldo, Staffan

2013-01-01

103

Stakeholder participation in the management of North East Atlantic pelagic fish stocks : The future role of the Pelagic Regional Advisory Council in a reformed CFP  

DEFF Research Database (Denmark)

When the Regional Advisory Councils (RACs) were created during the last reform of the Common Fisheries Policy (CFP) in 2002, it was recognised that in addition to the five geographically orientated stakeholder lead advisory bodies, a separate RAC dedicated exclusively to pelagic fisheries was needed because of it being so distinctly different from other fisheries. Pelagic fishing is different mostly due to the fact that the targeted fish species behave in a unique manner by grouping in schools in mid-water unlike other commercially targeted fishes, which typically reside on or near the ocean floor. For this reason, as well as the fact that they are usually widely distributed, researching and managing this dynamic group of fishes across the borders of many countries requires a unique approach. Fortunately, despite these complexities, policy makers have succeeded to establish a reasonably well functioning management framework, which has lead to the situation that most pelagic fish stocks are harvested biologically sustainable. While a majority of Europe's fish stocks still need rebuilding, and the main aim accordingly is to reduce fishing mortality, the current focus for pelagic fish stocks is to improve the performance of already implemented Long Term Management plans in terms of their biological as well as social and economical objectives. This paper reflects upon experiences of the Pelagic Regional Advisory Council (PRAC) in its role as advisor to the EU institutions. Subsequently, in the context of ideas presented in the European Commission's Green paper, the authors discuss the future of the PRAC and conclude that its main development potential lies not with the current EU's CFP reform, but rather should be sought in a wider international context.

Coers, Aukje; Raakjær, Jesper

2012-01-01

104

ASSESSMENT OF BIOTIC INTEGRITY USING FISH COMMUNITIES  

Science.gov (United States)

Man's activities have had profound, and usually negative, influences on freshwater fishes from the smallest streams to the largest rivers. Some negative effects are due to contaminants, while others are associated with changes in watershed hydrology, habitat modifications, and al...

105

ASSESSMENT AND RECOGNITION OF STOCKS IN ACCOUNTING ACCORDING TO INTERNATIONAL STANDARD OF FINANCIAL REPORT IAS 2 – STOCKS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In life accounts of an enterprise stocks represent a very important topic in the light of their c ost reflected in theprofit and loss account on the one hand, and the value of assets shown in the balance sheet on the other hand.In practice are met two categories of enterprises for which stock accounting are very important.The first category is represented by commodities traders, who have typically a single class of stock: goods. Inthis case the trader buys stocks for the purpose of resale. Th...

2009-01-01

106

Assessment of the North-East Arctic and North Sea Stocks of Saithe Taking Into Account Migration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tagging experiments have shown that there is a substantial migration of young saithe from the Norwegian coast north of 62°N to the North Sea. Assessments of the North-East Arctic and North Sea Stocks of saithe were made assuming that all 1-4 year old saithe caught between 62° and 64°N would have recruited to the North Sea stock. The new assessments give a decrease in the level of recruitment to the North-East Arctic stock and an increase to the North Sea stock. he exploitation of the Nort...

Jakobsen, Tore

1981-01-01

107

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

108

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

109

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

110

Grass Carp Stocking Rate Model (AMUR/STOCK).  

Science.gov (United States)

The AMUR/STOCK model is a coupled plant growth and fish feeding and bioenergetics simulation model that evaluates the effectiveness of grass carp stocking rate strategies for controlling nuisance growth of aquatic plants under user-selected site condition...

R. M. Stewart W. A. Boyd

1999-01-01

111

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Leonardo Nanni Costa; Mario Sapino; Sergio Pippione; Giovanni Mattalia; Mauro Saracco; Savino Di Trani; Cesare Zanasi

2012-01-01

112

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Goran Vuji?; Jovic?ic?, Nebojs?a M.; Milun Babi?; Stanisavljevic?, Nemanja S.; Batinic?, Bojan J.; Aleksandar Pavlovi?

2010-01-01

113

Increasing public involvement in enriching our fish stocks through genetic enhancement.  

Science.gov (United States)

A total of 70%, of the world's conventional commercial fish species are now fully exploited, overexploited, depleted or recovering from depletion. This dramatic crash in the capture world fisheries production has led to problems in foods distribution, balance of payments, employment, and ecological depletion. Public support for breeding programs with terrestrial farm animals and plants in agriculture have revolutionized this industry over the past few hundred years. However, new genetic rearing technologies to improve marine animal production through aquaculture that utilize modern biology to obtain sustainable aquaculture and preserve biodiversity provide a promise to address these problems. However aquaculture has not been subject to public discussion and approval. Public involvement, not necessarily acquiescence, provide value added in the decision making process. Public understanding and involvement involves three stages. (i) Public concern over the pool of genetic information; (ii) if aquaculture is to respond to the fisheries crises with innovation, the knowledge gap between public understanding and scientific information must be bridged; and (iii) strategies must be developed for achieving this. Release of recombinant DNA to the environment, and handling exotic species, are useful case studies. Illustrations will be given of communication bridges to the public and ways to involve the public in making policy decisions. PMID:10596744

Halvorson, H O; Quezada, F

1999-11-01

114

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

Directory of Open Access Journals (Sweden)

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

115

Fish behavior, migration and environmental assessment  

Energy Technology Data Exchange (ETDEWEB)

Studies at the Pacific Northwst Laboratory have evaluated fish behavior and migration in response to thermal discharge, gas supersaturated water, water-soluble fractions of coal liquids, and other environmental stresses. Major findings including thermal discharges did not block upstream migration of sonic-tagged adult chinook salmon (Oncorhynchus tschawytscha) and a rainbow trout (Salmo gairdneri) in the Columbia River. Juvenile chinook slamon avoided thermal discharges in the laboratory when ..delta..ts exceeded 9 to 11)degree)C above ambient. However juvenile salmon were more susceptible to predation at 10 to 20% of the thermal dose causing loss of equilibrium. Radio-tagged adult chinook salmon swam deeper in supersaturated water than in normally saturated water in the Snake River and, thereby, avoided the upper, critical zone. Carp (Cyprinus carpio) and black bullhead (Ictalurus melas) did not always avoid lethal gas levels in the laboratory and some fish died in the test apparatus. Fathead minnow (Pimephales promelas) avoided the water soluble fraction (WSF) of a coal liquid at concentrations causing acute effects but not at those causing chronic effects. Rainbow trout did not avoid coal liquid WSFs although they reportedly avid the major constituent, phenol, tested a as pure compound. Susceptibility to predation of juvenile rainbow trout did not increase until phenol concentrations reached the acute LC/sub 50/. 67 refs., 11 figs., 1 tab.

Gray, R.H.

1988-02-01

116

Virgin Islands Biosphere Reserve. Research Report No. 8. Map of Fishery Habitats within the Virgin Islands Biosphere Reserve. Research Report No. 9. Fisheries Habitat of the Virgin Islands Region of Ecological Importance to the Fishery Resources of the Virgin Islands Biosphere Reserve. Research Report No. 10. Assessment of Fish and Shellfish Stocks Produced in the Biosphere Reserve.  

Science.gov (United States)

Nineteen naturally occurring and one man-made benthic community habitat types are described in terms of the commercially important fish species assemblages found occurring there. Marine habitat types were mapped for all of St. John from National Oceanogra...

R. H. Boulon A. E. Dammann

1986-01-01

117

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)

2010-02-01

118

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.

2010-02-01

119

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 vesselsâ?? 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

120

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

 
 
 
 
121

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 â??Celtic Seasâ? (CS) and â??Greater North Seaâ? 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

122

Assessment of fish freshness with an electronic nose  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish En este trabajo se analiza el desempeño de un prototipo de nariz electrónica, desarrollado en nuestros laboratorios para detectar el grado de conservación de la carne de pescado. El presente estudio es parte de un proyecto en marcha para crear protocolos para el control de calidad en el sector pesqu [...] ero argentino, una creciente demanda debido a razones de exportación y a nuevas regulaciones locales de control vigentes. La calidad de la carne de pescado es un concepto complejo que incluye información y control de todas las etapas, desde la zona de pesca hasta su consumo final. En este trabajo tomamos sólo un aspecto, el deterioro de la calidad de carne de filetes crudos debido a fallas en el almacenamiento refrigerado. Abstract in english In this work the performance of a prototype of electronic nose, developed in our laboratories, to assess fish freshness is analized. The present study is part of an ongoing project to perform quality assurance protocols for the Argentine fish sector, an increasing demand due to export reasons and ne [...] w national food control regulations. Fish quality is a complex concept involving a whole range of factors, freshness being one of the most important. The complete quality assessment of fish meat includes information and control of all the steps, from catching area to final consumption. In this work we address one aspect, quality deterioration of "raw fillets" due to frozen storage defects.

D.F, Rodríguez; S, Reich; P, Alonso; M, Szudruk; C, Arrieta; H, Lacomi; C, Gillari; A, Boselli; A, Lamagna.

123

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

124

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 24â??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 surveyâ?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 onâ?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

125

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

126

Improving the assessment of instream flow needs for fish populations  

Energy Technology Data Exchange (ETDEWEB)

Instream flow requirements are one of the most frequent and most costly environmental issues that must be addressed in developing hydroelectric projects. Existing assessment methods for determining instream flow requirements have been criticized for not including all the biological response mechanisms that regulate fishery resources. A new project has been initiated to study the biological responses of fish populations to altered stream flows and to develop improved ways of managing instream flows. 21 refs., 3 figs.

Sale, M.J. (Oak Ridge National Lab., TN (USA)); Otto, R.G. (Otto (R.G.) and Associates, Arlington, VA (USA))

1991-01-01

127

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

128

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

129

The use of acoustic and bottom trawl surveys in the assessment of north-east arctic cod and haddock stocks [fra "a workshop on comparative biology, assessment and management of gadoids from the North Pacific and Atlantic oceans" 24-28 June, 1985 Seattle, Washington  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years survey results constitute the most important part of the material on which the stock assessments of North-east Arctic cod and haddock are based. Both acoustic surveys and bottom trawl surveys have been applied. The acoustic surveys were carried out in January-April each year, covering the young fish grounds of both species in the Barents Sea and the spawning grounds for cod along the Norwegian coast. The bottom trawl surveys covered the young fish grounds in the Barents Sea du...

Hylen, Arvid; Nakken, Odd; Sunnana?, Knut

1986-01-01

130

Combining Turbine Blade-Strike and Life Cycle Models to Assess Mitigation Strategies for Fish Passing Dams  

Energy Technology Data Exchange (ETDEWEB)

Combining the two models produced a rapid, cost effective tool for assessing dam passage impacts to fish populations and prioritizing among mitigation strategies for conserving fish stocks in regulated rivers. Estimated mortality of juvenile and adult Atlantic salmon (Salmo salar) and sea trout (S. trutta) passing turbines at two dams in northern Sweden was significantly higher for Kaplan turbines compared to Francis turbines, and for adult fish compared to juveniles based on blade strike models. Mean probability of mortality ranged from 6.7% for salmon smolts passing Francis turbines to >100% for adult salmon passing Kaplan turbines. Life cycle modeling allowed benefits to be assessed for three alternatives that mitigated this mortality. Salmon population responses varied considerably among alternatives and rivers: growth rates improved as much as 17.9%, female escapements increased up to 669%, and more than 1,300 additional female salmon were produced in one case. Protecting both smolts and adults provided benefits, and in one river, mitigating turbine mortality alone was estimated to have met the production capacity of the available habitat.

Ferguson, John W.; Ploskey, Gene R.; Leonardsson, Kjell; Zabel, Richard W.; Lundqvist, Hans

2008-08-01

131

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

132

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

133

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

134

Climate Change Vulnerability of Native and Alien Freshwater Fishes of California: A Systematic Assessment Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status o...

Moyle, Peter B.; Kiernan, Joseph D.; Crain, Patrick K.; Quin?ones, Rebecca M.

2013-01-01

135

The state of stocks of cod, whiting, sole and plaice on the west and southwest coasts of Ireland  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stocks of cod, whiting, plaice and sole in ICES Divisions VIIb,c and VIIj,k are an important part of the Irish fishing resource yet, until 1993, were not subject to any assessment. Landings of these stocks in 1996 were valued at £8.6 million, representing 17% of the overall value of all Irish landings of demersal species. In 1993, the Fisheries Research Centre initiated a stock monitoring programme with the aim of providing adequate data to enable an assessment of these stocks. This paper pr...

Wheatley, S. B.; Connolly, P. L.; Woods, F.; Keatinge, M.; Doherty, M.

1999-01-01

136

50 CFR 648.90 - NE multispecies assessment, framework procedures and specifications, and flexible area action...  

Science.gov (United States)

...assessment, framework procedures and...multispecies framework specification...annual Stock Assessment and Fishery...updated groundfish assessment, peer-reviewed...pertinent scientific work during the 2005...fishing mortality, social and economic...through future framework...

2009-10-01

137

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...

138

Methods for sampling fish communities as part of the National Water-Quality Assessment Program  

Science.gov (United States)

Fish community structure is characterized in the U.S. Geological Survey's National Water-Quality Assessment Program as part of an integrated physical, chemical, and biological assessment of the Nation's water quality. The objective of the National Water-Quality Assessment characterization of fish community structure is to relate fish community characteristics to physical, chemical, and other biological factors to assess water-quality conditions. To accomplish this, fish community structure is described at sites representing selected environmental settings. In addition, spatial and temporal patterns in fish community structure are examined at local, regional, and national levels. A representative sample of the fish community is collected by sampling a stream reach using two complementary methods. The primary collection method is electrofishing using backpack, towed, or boat-operated electrofishing gear; seining is a secondary technique. Other secondary techniques may be substituted after careful consideration of sampling efficiency and consultation with local fish ecologists. Before fish sampling is conducted, careful consideration must be given to collecting permits; protecting endangered, threatened, and special-concern species; and coordinating sampling efforts with other fish ecologists. After the sample is collected, individual fish are identified to species by ichthyologists. Length and weight measurements are taken, and the presence of external anomalies are recorded.

Meador, M. R.; Cuffney, T. F.; Gurtz, M. E.

1993-01-01

139

Assessment of Sr, Cs and K radionuclide equilibrium concentration factors in Danube fish  

International Nuclear Information System (INIS)

Measurements based upon fallout activity were carried out for assessing some equilibrium concentration factors in fish of the Austrian region of the Danube river, the radionuclides being Cs-137, Sr-90 and K-40. Mean values were found as 250 for Cs-137 and 7 for Sr-90 in fish tissue and as 350 for Sr-90 in fish bone, and 1.2x103 for K-40. Well proved log-normal distributions for Cs-137 in fish tissue and Sr-90 in fish bone and a normal distribution for K-40 satisfactorily describe the scattering of data. (orig.)

1988-01-01

140

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 c...

Terziyski, Doychin I.; Kalchev, Roumen K.; Vasileva, Penka L.; Piskov, Ivaylo A.; Iliev, Ivan Z.

2009-01-01

 
 
 
 
141

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

142

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

International Nuclear Information System (INIS)

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)

2010-03-01

143

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

International Nuclear Information System (INIS)

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.

2010-03-01

144

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

145

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

146

Fish pass assessment by remote control: a novel framework for quantifying the hydraulics at fish pass entrances  

Science.gov (United States)

Fragmentation of aquatic habitats can lead to the extinction of migratory fish species with severe negative consequences at the ecosystem level and thus opposes the target of good ecological status of rivers defined in the EU Water Framework Directive (WFD). In the UK, the implementation of the EU WFD requires investments in fish pass facilities of estimated 532 million GBP (i.e. 639 million Euros) until 2027 to ensure fish passage at around 3,000 barriers considered critical. Hundreds of passes have been installed in the past. However, monitoring studies of fish passes around the world indicate that on average less than half of the fish attempting to pass such facilities are actually successful. There is a need for frameworks that allow the rapid identification of facilities that are biologically effective and those that require enhancement. Although there are many environmental characteristics that can affect fish passage success, past research suggests that variations in hydrodynamic conditions, reflected in water velocities, velocity gradients and turbulences, are the major cues that fish use to seek migration pathways in rivers. This paper presents the first steps taken in the development of a framework for the rapid field-based quantification of the hydraulic conditions downstream of fish passes and the assessment of the attractivity of fish passes for salmonids and coarse fish in UK rivers. For this purpose, a small-sized remote control platform carrying an acoustic Doppler current profiler (ADCP), a GPS unit, a stereo camera and an inertial measurement unit has been developed. The large amount of data on water velocities and depths measured by the ADCP within relatively short time is used to quantify the spatial and temporal distribution of water velocities. By matching these hydraulic features with known preferences of migratory fish, it is attempted to identify likely migration routes and aggregation areas at barriers as well as hydraulic features that may distract fish away from fish pass entrances. The initial steps of the framework development have focused on the challenge of precise spatial data referencing in areas with limited sky view to navigation satellites. Platform tracking with a motorised Total Station, various satellite-based positioning solutions and simultaneous localisation and mapping (SLAM) based on stereo images have been tested. The effect of errors in spatial data referencing on ADCP-derived maps of flow features and bathymetry will be quantified through simultaneous deployment of these navigation technologies and the ADCP. This will inform the selection of a cost-effective platform positioning system in practice. Further steps will cover the quantification of uncertainties in ADCP data caused by highly turbulent flows and the identification of suitable ADCP data sampling strategies at fish passes. The final framework for fish pass assessment can contribute to an improved understanding of the interaction of fish and the complex hydraulic river environment.

Kriechbaumer, Thomas; Blackburn, Kim; Gill, Andrew; Breckon, Toby; Everard, Nick; Wright, Ros; Rivas Casado, Monica

2014-05-01

147

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

2007-02-01

148

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

149

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

150

Assessment of micronuclei induction in peripheral erythrocytes of fish exposed to xenobiotics under controlled conditions.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of the present study was to standardize and to assess the predictive value of the cytogenetic analysis by MN test in fish erythrocytes as a biomarker for marine environmental contamination. MN frequency baseline in erythrocytes was evaluated in a number of fish species from a reference area (S. Teresa, La Spezia Gulf) and genotoxic potential of a number of common chemical contaminants and mixtures was determined in fish experimentally exposed in aquarium under controlled conditions. F...

Bolognesi, Claudia; Perrone, Emanuela; Roggieri, Paola; Pampanin, Daniela M.; Sciutto, Andrea

2006-01-01

151

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

2007-04-01

152

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)

1992-01-01

153

A stochastic length-based assessment model for the Pandalus stock in Skagerrak and the Norwegian Deep  

DEFF Research Database (Denmark)

This working document describes a length based stochastic assessment model of Pandalus in ICES areas IIIA and IVA. The model describing stock development is age based, but the model also estimates the relation between age and length assuming a von Bertalany growth curve. The model presented in this paper is based on the assessment data presented at the 2012 NIPAG meeting, but with updated survey information. Also the estimates shown here are based on equal standard deviations for survey and catch L = (c) L , which is the natural assumption, as this parameter describes the standard deviation of the length distribution in the population

Nielsen, Anders; Munch-Petersen, Sten

2013-01-01

154

Bio-economic management strategy evaluation of deepwater stocks using the FLBEIA model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Deepwater fish are characterized by long lifespans, late maturity and low productivity. This implies slow recovery from low biomass levels and it is, therefore, important to manage these stocks correctly to avoid overfishing. However, these stocks are generally data poor, which it makes difficult to apply quantitative assessment models on which to base their management. The management strategy evaluation (MSE) approach consists in evaluating the performance of management strategies by simulat...

Garcia, Dorleta; Urtizberea, Agurtzane; Diez, Guzman; Gil, Juan; Marchal, Paul

2013-01-01

155

Impact Assessment for the Reduction in Fishing ... - ARCHIVE: Defra  

quality fresh fish and maintaining the character and cultural identity of small .... \\group. A second distinct group is made up of vessels over 9m in length and with \\.... Such groups offer a sense of community attachment or solidarity, which can \\help to ... and profitable future for UK fishing, 2004, Prime Minister's Strategy Unit.

156

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

1996-01-01

157

Genetic stock assessment of spawning arctic cisco (Coregonus autumnalis) populations by flow cytometric determination of DNA content.  

Science.gov (United States)

Intraspecific variation in cellular DNA content was measured in five Coregonus autumnalis spawning populations from the Mackenzie River drainage, Canada, using flow cytometry. The rivers assayed were the Peel, Arctic Red, Mountain, Carcajou, and Liard rivers. DNA content was determined from whole blood preparations of fish from all rivers except the Carcajou, for which kidney tissue was used. DNA content measurements of kidney and blood preparations of the same fish from the Mountain River revealed statistically indistinguishable results. Mosaicism was found in blood preparations from the Peel, Arctic Red, Mountain, and Liard rivers, but was not observed in kidney tissue preparations from the Mountain or Carcajou rivers. The Liard River sample had significantly elevated mean DNA content relative to the other four samples; all other samples were statistically indistinguishable. Significant differences in mean DNA content among spawning stocks of a single species reinforces the need for adequate sample sizes of both individuals and populations when reporting "C" values for a particular species. PMID:2036920

Lockwood, S F; Bickham, J W

1991-01-01

158

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  

Directory of Open Access Journals (Sweden)

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

159

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

160

Environmental Assessment for the Northeast Skate Complex Fishing Year 2010-11 Specifications.  

Science.gov (United States)

In support of and consistent with the provisions of Amendment 3 to the Skate Complex Fishery Management Plan (FMP), this environmental assessment analyzed the expected environmental impacts of the final specifications for the skate fishery, for fishing ye...

2010-01-01

 
 
 
 
161

Assessing the impact of power plant mortality on the compensatory reserve of fish populations  

International Nuclear Information System (INIS)

A technique is presented to quantify the concepts of compensation and compensatory reserve in exploited fish populations. The technique was used to examine the impact of power plant mortality on a hypothetical striped bass population. Power plant mortality had a more severe impact on the compensation ratio and compensatory reserve for an exploited stock. The technique can be applied to determine a critical compensation ratio which could serve as a standard against which additional sources of mortality, such as those caused by power plants, could be measured

1977-05-02

162

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

163

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.

164

Assessment of global scale impacts on soil organic carbon stocks under different climate change scenarios  

Science.gov (United States)

Predictions of future climate encompass uncertainties, either due to the specific model implementation or due to the use of different models. In this study we assess the response at the global scale of soil organic carbon (SOC) stocks to the variability of climate inputs derived from global circulation models (GCM). A consistent global data set at 0.5 degree resolution of climate, soil and land use data has been compiled. This allows a consistent approach to be used to assess geographic variability in the impacts of climate change on SOC. For this study, two SRES climate scenarios (A1B, B2) and two climate forcing scenarios (+2? C and +4?C in 2050) were chosen using a pattern-scaling approach. Each climate scenario is obtained from seven different GCMs. Monthly temperature and precipitation were obtained from the GCMs, and yearly net primary production (NPP) and 5 yearly land-use information were obtained from the IMAGE model. These data were used to drive the SOC model RothC from 1970 up to 2100. The RothC model is one of the most widely used SOC models and has been evaluated in a wide variety of ecosystems including croplands, grasslands and forests and in various climate regions. The IMAGE model only provides NPP and land use surfaces per SRES. To provide consistency between the driving climate variables and NPP data, the latter were scaled using the MIAMI NPP model. The MIAMI NPP model is a simple conceptual model that links NPP to long-term annual mean air temperature and total annual precipitation. NPP is limited by either one. The MIAMI model assumes that NPP increases with increasing temperature and precipitation. For each simulation of the climate scenario, a corresponding NPP surface was constructed, which in turn was used to scale the plant input values generated by the model. Land use change is assumed to be independent of climate change within the seven GCM simulations of each SRES. For the climate forcing scenarios, the NPP and land use surfaces of SRES A1B of the IMAGE model was used. RothC simulations were carried out in two ways: a) no land use change and b) including land use change. This allows the impact due only to climate change and land use to be distinguished. Initial results of the simulations of arable land use (no land use change) show a general increase in the global average SOC concentrations under A1B from 56 t ha-1 up to 59-63 t ha-1 in 2100. However, different trends can be observed at regional scale. Average arable SOC concentrations of Western Europe start off at 75.6 t ha-1 in 1970 and vary between 75 and 79 t ha-1 in 2100. A relatively high increase in SOC is observed in the Caribbean, with a rise from 43 up to 69 - 72 t ha-1. In warmer climates, SOC decomposition increases where soil moisture is not limiting. NPP also increases under higher temperatures. These two processes tend to cancel each other out in Western Europe, as suggested by other studies. However, in the example region of the Caribbean, an increase in NPP overrides increased decomposition and results in higher SOC concentrations.

Gottschalk, Pia; Arnell, Nigel; Osborn, Tim; Wattenbach, Martin; Smith, Jo; Smith, Pete

2010-05-01

165

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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&...

2012-01-01

166

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Hosseyn Karbasi Yazdi; Kobra Hemmati; Ali Bayat

2012-01-01

167

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

168

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.

169

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

170

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

171

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

Directory of Open Access Journals (Sweden)

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

172

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

Directory of Open Access Journals (Sweden)

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

173

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

174

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

2008-03-01

175

Combining Telephone Surveys and Fishing Catches Self-Report: The French Sea Bass Recreational Fishery Assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fisheries statistics are known to be underestimated, since they are mainly based on information about commercial fisheries. However, various types of fishing activities exist and evaluating them is necessary for implementing effective management plans. This paper assesses the characteristics and catches of the French European sea bass recreational fishery along the Atlantic coasts, through the combination of large-scale telephone surveys and fishing diaries study. Our results demonstrated tha...

Rocklin, Delphine; Levrel, Harold; Drogou, Mickael; Herfaut, Johanna; Veron, Gerard

2014-01-01

176

FISH AND SHELLFISH PRODUCTS DISTRIBUTED BY "ETHNIC" MINI-MARKET: CONFORMITY ASSESSMENT TO CURRENT LEGISLATION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this study was to conduct an assessment on the quality and methods for marketing of fish products sold by ethnic minimarket. Has been inspected 20 supermarkets and buyed 60 fish and shellfish samples. The neatness of the rooms were evaluated during the shopping in the markets. Products purchased in the supermarket (about three samples for each shop) were brought in Ichthypathology laboratory of State Veterinary Institute of Piedmont, Liguria and Aosta Valley, in Turin. Were con...

Giorgi, I.; Pavoletti, E.; Arsieni, P.; Prearo, M.

2012-01-01

177

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...

2009-01-01

178

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

Directory of Open Access Journals (Sweden)

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

179

Closed recirculating culture of scorpaenid fish and puffer fish. Examination of nitrogen-excretion rate, proper stocking density and optimum temperature, and rearing experiments; Junkan roka hoshiki ni yoru oniokoze oyobi torafugu yogyo gijutsu no kaihatsu. Chisso haishutsuryo, tekisei shuyo mitsudo, koteki suion no kaimei oyobi shiiku shiken  

Energy Technology Data Exchange (ETDEWEB)

Nitrogen excretion rate, proper stocking density, and optimum temperature for growth were examined on scorpaenid fish and puffer fish to establish closed recirculating culture techniques. Nitrogen excretion rate of scorpaenid fish about 5, 10 and 150 g in body weight was 20, 28 and 10 mg-N/100 g/day after feeding, respectively. Necessary volume of net filter medium to produce 1 kg of fish was estimated to be 1 liter. Growth rate and survival rate of fish were not affected by rearing density of 10 to 30 kg/m{sup 2}-bottom area of cage. The optimum temperature for the growth was 27degC regardless of development stage. Nitrogen excretion rate of puffer fish about 23 g in body weight was 60 mg-N/100 g/day after feeding. Necessary volume of net filter medium to produce 1 kg of fish was estimated to be 2 liters. Growth rate of fish was not affected by rearing density of 6 to 50 kg/m{sup 3}-volume of cage. However, a survival rate was slightly decreased as the rearing density increased. For the fish of 3 g in body weight, growth at 18degC was significantly inferior to those at 21, 24 and 27degC. For the fish of 54 g, growth at 25degC was superior to those at 15, 20 and 30degC. Survival rate of both sizes of fish was decreased as the temperature increased. 59 refs., 9 figs., 9 tabs.

Furuta, T.; Kikuchi, K.; Iwata, N.; Honda, H. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

1997-03-01

180

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...

 
 
 
 
181

Mercury concentrations in Maine sport fishes  

Energy Technology Data Exchange (ETDEWEB)

To assess mercury contamination of fish in Maine, fish were collected from 120 randomly selected lakes. The collection goal for each lake was five fish of the single most common sport fish species within the size range commonly harvested by anglers. Skinless, boneless fillets of fish from each lake were composited, homogenized, and analyzed for total mercury. The two most abundant species, brook trout Salvelinus fontinalis and smallmouth bass Micropterus dolomieu, were also analyzed individually. The composite fish analyses indicate high concentrations of mercury, particularly in large and long-lived nonsalmonid species. Chain pickerel Esox niger, smallmouth bass, largemouth bass Micropterus salmoides, and white perch Morone americana had the highest average mercury concentrations, and brook trout and yellow perch Perca flavescens had the lowest. The mean species composite mercury concentration was positively correlated with a factor incorporating the average size and age of the fish. Lakes containing fish with high mercury concentrations were not clustered near known industrial or population centers but were commonest in the area within 150 km of the seacoast, reflecting the geographical distribution of species that contained higher mercury concentrations. Stocked and wild brook trout were not different in length or weight, but wild fish were older and had higher mercury concentrations. Fish populations maintained by frequent introductions of hatchery-produced fish and subject to high angler exploitation rates may consist of younger fish with lower exposure to environmental mercury and thus contain lower concentrations than wild populations.

Stafford, C.P. [Univ. of Maine, Orono, ME (United States); Haines, T.A. [Geological Survey, Orono, ME (United States)

1997-01-01

182

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.

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

183

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, 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

2005-03-01

184

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}g/g dry wt. About 3% of the samples contained Hg levels exceeding the no observed adverse effects level (NOAEL) of WHO (50 {mu}g/g) and the levels in some hair samples of women also exceeded the NOAEL (10 {mu}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 {mu}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, 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.

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, Nagano 390-8621 (Japan); Iwata, Hisato [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); Tana, Touch Seang [Social and Cultural Observation Unit (OBSES) of the Cabinet of the Council of Ministers, Phnom Penh (Cambodia); Subramanian, Annamalai [Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan); 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

2005-03-01

185

Modeling the stochastic dynamics of the aggregate stock in collapsed fisheries: The case of the Northern cod stock  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Motivated by the evidence that many collapsed stocks have failed to recover despite the fact that fishing mortality has been reduced, or even when a moratorium is in effect, we develop a methodological approach using splines to analyze the stochastic population dynamics of fish stocks at low stock levels. Considering the aggregate Northern cod stock by way of illustration, we find that the species’ lack of recovery, despite the moratorium which still remains in force, is consistent with the...

Maroto Ferna?ndez, Jose? Mari?a; Mora?n Cabre?, Manuel

2013-01-01

186

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

187

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

Science.gov (United States)

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

188

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

189

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

1982-01-01

190

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

191

Assessment and reduction of the power consumption in refining paper stock  

Energy Technology Data Exchange (ETDEWEB)

Paper and board making stock is refined in order to produce the properties needed in the manufactured product. Experiments using bleached softwood and bleached hardwood sulphate pulps have shown that particular values of paper breaking length can be obtained by different combinations of values of the power applied to the refiner and the mass flow rate of stock through it. The total specific refining energy used, however, is very dependent on the combination and can differ by more than 30%. In practice, the power and mass flow rate also have to satisfy other requirements, such as the ability of the pulp to receive the power and the time available to process a tonne of pulp. With proper control refining energy could be saved in many mills; a targeted saving of 10% is realistic. The overall saving in the UK paper and board making industry could equal 24 ktoe, financially worth pounds 2.48 (3.72M EUA) per annum. In the EEC as a whole 10% reduction in refining energy would save approximately 164 ktoe per year, worth about 25.4M EUA. In a fine paper mill making 10,000 tonnes p.a. the payback time on the necessary control equipment would be 2 to 4 years, but the viability of the investment would vary from mill-to-mill. A description of the equipment and of the measurement of pulp and paper properties is given. Experimental work was carried out in the Bolton Emerson Claflin 01 refiner installed in a pilot plant.

Burkitt, P.G.; Gates, E.R.; Moore, M.W.

1981-01-01

192

Assessment of micronuclei induction in peripheral erythrocytes of fish exposed to xenobiotics under controlled conditions  

International Nuclear Information System (INIS)

The aim of the present study was to standardize and to assess the predictive value of the cytogenetic analysis by MN test in fish erythrocytes as a biomarker for marine environmental contamination. MN frequency baseline in erythrocytes was evaluated in a number of fish species from a reference area (S. Teresa, La Spezia Gulf) and genotoxic potential of a number of common chemical contaminants and mixtures was determined in fish experimentally exposed in aquarium under controlled conditions. Fish (Scophthalmus maximus) were exposed for 3 weeks to 50 ppb of single chemicals (dialkyl phthalate, bisphenol A, tetrabromodiphenyl ether), 30 ppb nonylphenol and mixtures (North Sea oil and North Sea oil with alkylated phenols). Chromosomal damage was determined as micronuclei (MN) frequency in fish erythrocytes. Nuclear anomalies such as blebbed, notched and lobed nuclei were also recorded. Significant increase in MN frequency was observed in erythrocytes of fish exposed to bisphenol A and tetrabromodiphenylether. Chemical mixture North Sea oil + alkylated phenols induced the highest MN frequency (2.95 micronucleated cells/1000 cells compared to 1 MNcell/1000 cells in control animals). The study results 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

2006-06-01

193

Assessment of micronuclei induction in peripheral erythrocytes of fish exposed to xenobiotics under controlled conditions  

Energy Technology Data Exchange (ETDEWEB)

The aim of the present study was to standardize and to assess the predictive value of the cytogenetic analysis by MN test in fish erythrocytes as a biomarker for marine environmental contamination. MN frequency baseline in erythrocytes was evaluated in a number of fish species from a reference area (S. Teresa, La Spezia Gulf) and genotoxic potential of a number of common chemical contaminants and mixtures was determined in fish experimentally exposed in aquarium under controlled conditions. Fish (Scophthalmus maximus) were exposed for 3 weeks to 50 ppb of single chemicals (dialkyl phthalate, bisphenol A, tetrabromodiphenyl ether), 30 ppb nonylphenol and mixtures (North Sea oil and North Sea oil with alkylated phenols). Chromosomal damage was determined as micronuclei (MN) frequency in fish erythrocytes. Nuclear anomalies such as blebbed, notched and lobed nuclei were also recorded. Significant increase in MN frequency was observed in erythrocytes of fish exposed to bisphenol A and tetrabromodiphenylether. Chemical mixture North Sea oil + alkylated phenols induced the highest MN frequency (2.95 micronucleated cells/1000 cells compared to 1 MNcell/1000 cells in control animals). The study results 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.

Bolognesi, Claudia [Environmental Carcinogenesis Unit, National Institute for Research on Cancer, L.go Rosanna Benzi, 10, 16132 Genoa (Italy)]. E-mail: claudia.bolognesi@istge.it; Perrone, Emanuela [Environmental Carcinogenesis Unit, National Institute for Research on Cancer, L.go Rosanna Benzi, 10, 16132 Genoa (Italy); Roggieri, Paola [Environmental Carcinogenesis Unit, National Institute for Research on Cancer, L.go Rosanna Benzi, 10, 16132 Genoa (Italy); Pampanin, Daniela M. [IRIS - International Research Institute of Stavanger AS, Mekjarvik 12, N-4070 Randaberg (Norway); Sciutto, Andrea [Environmental Carcinogenesis Unit, National Institute for Research on Cancer, L.go Rosanna Benzi, 10, 16132 Genoa (Italy)

2006-06-01

194

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.

Kell, L.T.; Pilling, G.M.

2006-01-01

195

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

Energy Technology Data Exchange (ETDEWEB)

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.

McKinstry, Craig A.; Simmons, Mary Ann; Simmons, Carver S.; Johnson, Robert L.

2005-04-01

196

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

2005-01-01

197

Use of artificial substrates to enhance production of fresh water herbivorous fish in pond culture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two trials were conducted in mud-bottomed concrete tanks to assess the potential of using artificial substrates to enhance fish production in ponds. Three substrate types were tested: bamboo poles, PVC pipes and sugarcane bagasse bundles. In one trial, periphyton was grown on the substrates in the absence of fish. In the second trial, masheer (Tor khudree Sykes) fingerlings were stocked at three densities. Results showed a significant effect of substrate type on fish growth (P 0.001) and on n...

2001-01-01

198

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

199

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

Directory of Open Access Journals (Sweden)

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

200

An assessment of the DNA barcodes of Indian freshwater fishes.  

Science.gov (United States)

Freshwater fishes in India are poorly known and plagued by many unresolved cryptic species complexes that masks some latent and endemic species. Limitations in traditional taxonomy have resulted in this crypticism. Hence, molecular approaches like DNA barcoding, are needed to diagnose these latent species. We have analyzed 1383 barcode sequences of 175 Indian freshwater fish species available in the databases, of which 172 sequences of 70 species were generated. The congeneric and conspecific genetic divergences were calculated using Kimura's 2 parameter distance model followed by the construction of a Neighbor Joining tree using the MEGA 5.1. DNA barcoding principle at its first hand approach, led to the straightforward identification of 82% of the studied species with 2.9% (S.E=0.2) divergence between the nearest congeners. However, after validating some cases of synonymy and mislabeled sequences, 5% more species were found to be valid. Sequences submitted to the database under different names were found to represent single species. On the other hand, some sequences of the species like Barilius barna, Barilius bendelisis and Labeo bata were submitted to the database under a single name but were found to represent either some unexplored species or latent species. Overall, 87% of the available Indian freshwater fish barcodes were diagnosed as true species in parity with the existing checklist and can act as reference barcode for the particular taxa. For the remaining 13% (21 species) the correct species name was difficult to assign as they depicted some erroneous identification and cryptic species complex. Thus, these barcodes will need further assay and inclusion of barcodes of more specimens from same and sister species. PMID:24378233

Chakraborty, Mohua; Ghosh, Sankar Kumar

2014-03-01

 
 
 
 
201

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  

International Nuclear Information System (INIS)

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

1982-01-01

202

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China.  

Science.gov (United States)

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd>Zn>Cu>Pb for fishpond 1 and Zn>Cd>Cu>Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one. PMID:23508535

Zhuang, Ping; Li, Zhi-an; McBride, Murray B; Zou, Bi; Wang, Gang

2013-08-01

203

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

204

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

205

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.

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

206

Risk assessments of human exposure to bioaccessible phthalate esters through market fish consumption.  

Science.gov (United States)

The bioaccessibility of phthalate esters in 20 fish species collected from Hong Kong market was evaluated using an in vitro gastrointestinal model. The ?phthalate ester concentration detected in fresh water fish ranged from 1.66 to 3.14?g/g wet weight (ww) and in marine fish ranged from 1.57 to 7.10?g/g ww, respectively. di-2-Ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) were the predominant compounds in both freshwater fish and marine fish. The digestible concentrations of phthalate esters ranged from 0.20 to 1.23?g/g ww (mean 0.35?g/g ww), and account for 2.44 to 45.5% (mean 16.8%) for raw concentrations of phthalate esters. In the present study, the accumulation ratio Rnn value of all phthalate esters was greater than 1 except for diisobutyl phthalate (DIBP), DBP and di-n-hexyl phthalate (DHP), suggesting that these phthalate esters could be accumulated during gastrointestinal digestion. Based on this health risk assessment, most of fish species were considered safe for consumption, however Hong Kong residents should take caution when consuming Mud carp and Bighead carp. PMID:23688402

Cheng, Zhang; Nie, Xiang-Ping; Wang, Hong-Sheng; Wong, Ming-Hung

2013-07-01

207

TOXICOLOLIGCAL ASSESSMENT OF BIODEGRADED PENTACHLOROPHENOL: MICROTOX AND FISH EMBRYOS  

Science.gov (United States)

Results indicate that while biodegradation of PCP was nearly complete, other metabolites of the degradation process were toxic or teratogenic. hus, the M. beryllina bioassay allows extremely sensitive assessment of toxicity associated with biodegraded environmental pollutants and...

208

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.

209

Exploratory assessment of fish consumption among Asian-origin sportfishers on the St. Lawrence River in the Montreal region  

Energy Technology Data Exchange (ETDEWEB)

An exploratory survey was undertaken in the fall 1995 open-water fishing seasons with nine Bangladeshi and nine Vietnamese-origin sportfishers. A 70-item instrument assessing sportfishing practices and fish consumption habits was administered by dietitians in participants` homes. Two 24-h diet recalls and a fish consumption calendar permitted the assessment of fish intake in the overall dietary context. Annually, Bangladeshi fishers consumed 46.8 {+-} 25.6 sportfish meals, and Vietnamese fishers ate 40.7 {+-} 35.1 meals. Consumption of sportfish taken from the St. Lawrence River has the potential both for dietary benefit and for hazardous chemical exposure.

Shatenstein, B. [Sante au Travail et Environnementale, Montreal, Quebec (Canada). Regie Regionale de la Sante et des Services Sociaux de Montreal-Centre]|[Univ. de Montreal, Quebec (Canada). Dept. de Nutrition; Kosatsky, T.; Tapia, M.; Nadon, S.; Leclerc, B.S. [Sante au Travail et Environnementale, Montreal, Quebec (Canada). Regie Regionale de la Sante et des Services Sociaux de Montreal-Centre

1999-02-01

210

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

211

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Watterson, Andrew; Little, David; Young, James A.; Boyd, Kathleen; Azim, Ekram; Murray, Francis

2008-01-01

212

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Watterson, A.; Little, D.; Young, J. A.; Boyd, K.; Azim, E.; Murray, F.

2008-01-01

213

Assessing risks to fish populations near a proposed disposal facility for used nuclear fuel  

International Nuclear Information System (INIS)

The concept of used nuclear fuel disposal in the Canadian Shield is currently undergoing a federal environmental assessment review process. As part of this review, potential risks to brook trout populations in the vicinity of such an underground repository were considered. Chemical fate, transport and exposure models have been utilized to estimate the dose rates from released radionuclides and other fuel constituents, and these likely will not be sufficient to harm fish in nearby streams. However, other stressors such as habitat alteration (e.g., loss of upwelling) and/or fishing pressure associated with increased public access could have significant population impacts if the site is located in a pristine northern region. Population models are utilized to explore the risks of local population reduction for different combinations of fishing pressure and habitat degradation

1995-11-05

214

Developing a Bayesian framework for stock assessment and decision analysis of the red sea urchin fishery in Baja California, Mexico / 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  

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.

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

215

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

216

HABITAT USE BY NATIVE AND STOCKED TROUT (SALMO TRUTTA L. IN TWO NORTHEAST STREAMS, PORTUGAL  

Directory of Open Access Journals (Sweden)

Full Text Available Habitat use by stocked and native brown trout (Salmo trutta L. was assessed in two headwater streams of North-eastern Portugal. Underwater observations were made during the summer season in three successive years to evaluate the effect of supplemental trout stocking. Multivariate analysis techniques applied to data sets on microhabitat use were exploited to identify the focal elevation (distance of fish from the bottom, total depth and cover as the variables that contribute most to the discrimination between stocked and native trout. Preference curves computed for native and stocked trout of the same age (1+, showed a distinct pattern in their ability to explore the available microhabitat resources. Stocked trout tended to occupy deeper pools (total depth > 100 cm vs. 60-100 cm for native trout, holding higher focal elevations (140-160 cm vs. 22.5 cm and cover (combination of boulders and overhanging vegetation or undercut banks. Furthermore, a high poststocking movement of 80% hatchery-reared fish was verified just one month after their release, suggesting that stocking did not contribute to the sustainable populations in either stream, and is far from being an adequate management technique.

TEIXEIRA A.

2006-04-01

217

Distribution and activity of pelagic fish - acoustic studies in the Baltic Sea  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fisheries agencies around the Baltic Sea use hydroacoustics to assess stock sizes of herring and sprat. These assessments rely on the assumption that the acoustic properties of Baltic clupeids are the same as North Sea herring. This may lead to biased results, as system-specific differences in salinity and fish fat content may influence acoustic target strength. The acoustic properties of the Baltic clupeids were explored and a new relationship between target strength and fish length was deve...

2005-01-01

218

Development of methods for assessing the vulnerability of Australian residential building stock to severe wind  

International Nuclear Information System (INIS)

Knowledge of the degree of damage to residential structures expected from severe wind is used to study the benefits from adaptation strategies developed in response to expected changes in wind severity due to climate change. This study will inform government, the insurance industry and provide emergency services with estimates of expected damage. A series of heuristic wind vulnerability curves for Australian residential structures has been developed. In order to provide rigor to the heuristic curves and to enable quantitative assessment to be made of adaptation strategies, work has commenced to produce a simulation tool to quantitatively assess damage to buildings from severe wind. The simulation tool accounts for variability in wind profile, shielding, structural strength, pressure coefficients, building orientation, component self weights, debris damage and water ingress via a Monte Carlo approach. The software takes a component-based approach to modelling building vulnerability. It is based on the premise that overall building damage is strongly related to the failure of key components (i.e. connections). If these failures can be ascertained, and associated damage from debris and water penetration reliably estimated, scenarios of complete building damage can be assessed. This approach has been developed with varying degrees of rigor by researchers around the world and is best practice for the insurance industry.

2010-08-01

219

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

220

Diel vertical migration of major fish-species in Lake Victoria, East Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Understanding of migration patterns is essential in the interpretation of hydro-acoustic stock assessment data of partly demersal partly pelagic fish stocks. In this paper we provide this kind of information for some species that were common in the Mwanza Gulf of Lake Victoria in the 1980s, before and after the upsurge of introduced Nile perch (Lates niloticus). Detritivorous haplochromines and Nile tilapia (Oreochromis niloticus), both stay near the bottom during day and night. Feeding seems...

2004-01-01

 
 
 
 
221

Stereology as a tool to assess reproduction strategy and fecundity of teleost fishes : Integrated studies in Central Baltic herring (Clupea harengus L.)  

DEFF Research Database (Denmark)

In fish stock assessment, spawning stock biomass (SSB) is used as an index of stock reproductive potential (SRP), and proportionality is assumed between SSB and recruitment, i.e. offspring production. SSB is calculated as the sum of biomass proportions of sexually mature individuals per age group. However, evidence that SSB is not a reliable SRP indicator has accumulated over the past decades. The SSB estimation does not consider individual differences in fecundity, skipped spawning, timing of spawning or differences in reproductive traits between sexes, which may all fluctuate significantly, influenced by individual physiological condition. The Central Baltic herring has experienced a radical decline in SSB over the past decades. This is mainly due to overfishing. However, significant changes in Baltic Sea salinity and temperature have also altered herring prey composition and abundance, while reduction in the number of cod has caused sprat numbers and thereby food competition to increase. Together, this has resulted in a significant drop in Central Baltic herring physiological condition. The influence which this lowered condition may have on herring SRP, in terms of increased down-regulation and thereby lowered fecundity, skipped spawning and timing of spawning, has not been investigated and is not considered in assessment of the stock. The objective of the study was two-fold. Firstly, improve methods for quantification of oocyte recruitment dynamics by adapting and applying modern stereological methods to assess fecundity and reproductive strategies. The strength of the stereological method being that, in combination with conventional histological analysis, quantification of all oocyte categories is possible, as well as registration of qualitative characteristics relating to spawning history of individuals, and further that statistical evaluation of estimates and method is possible. Secondly, apply the stereological methods to fill in gaps in knowledge about Baltic Sea herring reproductive strategy under current environmental conditions, including oocyte recruitment pattern, fecundity determination and down-regulation, skipped spawning and spawning fidelity, and to understand how factors like condition may influence individual decision making and fitness regarding these reproductive traits. The stereological methods applied in this project constituted a powerful set of tools for quantification of oocyte dynamics in fish and were successfully implemented in herring ovaries for quantification of both oocyte numbers and sizes as well as total volume fraction of atretic oocytes, introducing a negligible error to the total variance of estimates. The histological nature of the stereological methods facilitated a ready validation of maturity data, distinguishing first time spawners from repeat spawners, as well as a ready recognition of ongoing oocyte recruitment in early maturity stages, early stage atresia, POFs and residual eggs. Analyzing a sample of females all collected during a short time frame in March 2008 covering various stages of maturation progression, we saw that oocyte recruitment followed the characteristic pattern of an iteroparous total spawner with determinate fecundity and group synchronous oocyte development. However, a significant fecundity down-regulation was apparent, which followed a three-step mechanism, resulting in low potential fecundity, but high relative potential fecundity compared to other herring stocks. Individual maturation progression revealed a substantial number of specimens with early developing ovaries, thereby being skipped or delayed spawners in accordance to the spring spawning season. Individual condition generally did not appear to influence fecundity regulation, but showed a strong correlation with degree of maturation progression, skipped or delayed spawners having significantly poorer condition than specimens expected to spawn during the spring spawning season. Results further indicated, that spawning occurs throughout the year in the Central Baltic herring population and that

Bucholtz, Rikke Hagstrøm

2013-01-01

222

Stock assessment of sprat and whiting in the Western Black Sea in relation to global and local anthropogenic factors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

L'évaluation à long terme du stock du sprat #Sprattus sprattus$ L. pour la période 1957-1992 et du merlan #Merlangius merlangus euxinus$ de 1976 à 1992 en mer Noire a été effectuée par l'analyse des cohortes (VPA, analyse virtuelle des populations). Les relations entre les paramètres des stocks de poisson (recrutement, biomasse féconde et taux de mortalité) et des variables environnementales (vitesse du vent et durée des événements de vent d'ouest, température de la mer, activit...

Prodanov, K. B.; Daskalov, G. M.; Mikhailov, K. R.; Maxim, K.; Ozdamar, E.; Shljakhov, V.; Chashchin, A.; Arkhipov, A.

1998-01-01

223

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...

Sawusdee, Amonsak; Songrak, Apirak

2009-01-01

224

Assessing lake typologies and indicator fish species for Italian natural lakes using past fish richness and assemblages  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to establish a fish-based typology of Italian lakes and identify possible reference and indicator fish species for each lake type, we analysed historical data on fish assemblages of all Italian natural lakes[0.5 km2 from the period prior to the major decline in water quality in the 1950s. General linear regression models showed the ecoregion and lake altitude being the best predictors of fish species richness. The number of species was significantly higher in the Alpine than in the M...

Volta, Pietro; Oggioni, Alessandro; Bettinetti, Roberta; Jeppesen, Erik

2011-01-01

225

Toxicological assessment of biodegraded pentachlorophenol: Microtox and fish embryos.  

Science.gov (United States)

A Gram-negative bacterium, Pseudomonas sp. strain SR3, was isolated from soil at a former wood treatment plant in north central Florida. The ability of this bacterium to degrade pentachlorophenol (PCP) was confirmed by growing cells in a basal salts medium in which PCP was the only source of carbon and energy. Degradation from a measured concentration of 39-40 micrograms PCP/ml to 0.0006 micrograms PCP/ml was observed within 120 h of incubation in the presence of PCP-induced cells of Pseudomonas sp. strain SR3. The initial cell density in these cultures was 6 x 10(6) cfu/ml. Microtox 5 min EC50 toxicity tests revealed that aqueous solutions of PCP, measured concentrations 39-40 micrograms/ml were toxic but that final biodegraded samples, 0.0006 micrograms PCP/ml were nontoxic. However, bioassays with embryonic inland silversides, Menidia beryllina, showed that the biodegraded samples were embryotoxic or teratogenic. Water containing added PCP at concentrations up to 30 times higher than measured in the final biodegraded samples was less toxic/teratogenic. These results indicate that while biodegradation of PCP was nearly complete, intermediate metabolites of the degradation process or undegraded impurities in PCP were toxic or teratogenic. Thus, the M. beryllina bioassay allows extremely sensitive assessment of toxicity associated with biodegraded environmental pollutants and may be a useful criterion for determining whether bioremediated water or soil is safe for discharge back into the environment. PMID:8466298

Middaugh, D P; Resnick, S M; Lantz, S E; Heard, C S; Mueller, J G

1993-02-01

226

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

227

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

228

Mercury speciation in fish muscles from major Czech rivers and assessment of health risks.  

Science.gov (United States)

The aim of this work was to determine the mercury and methylmercury content in muscle tissue of chub (Leuciscus cephalus L.), to assess the health risks of eating the fish and to determine the number of fish meat servings that are suitable for weekly consumption. Total mercury concentrations were determined using a single-purpose atomic absorption spectrophotometer AMA 254. Methylmercury concentrations were determined by gas chromatography. The location where the highest total mercury concentrations in fish muscle tissues were found was the Vltava - Vra?any (0.236±0.1001mg/kg(-1)), and the highest methylmercury concentration was found at the Labe - Ob?íství (0.231±0.1056mg/kg(-1)). The conclusion based on the data ascertained is that the locations from which the lowest number of fish meat servings can be eaten are the Vltava - Vra?any and the Labe - Ob?íství. The results of this study helped evaluate contamination levels of rivers that flow out of the Czech Republic. PMID:24360463

Sedlá?ková, Lenka; Kružíková, Kamila; Svobodová, Zde?ka

2014-05-01

229

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

230

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

1998-01-01

231

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

232

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

233

FISH AND SHELLFISH PRODUCTS DISTRIBUTED BY "ETHNIC" MINI-MARKET: CONFORMITY ASSESSMENT TO CURRENT LEGISLATION  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study was to conduct an assessment on the quality and methods for marketing of fish products sold by ethnic minimarket. Has been inspected 20 supermarkets and buyed 60 fish and shellfish samples. The neatness of the rooms were evaluated during the shopping in the markets. Products purchased in the supermarket (about three samples for each shop were brought in Ichthypathology laboratory of State Veterinary Institute of Piedmont, Liguria and Aosta Valley, in Turin. Were conducted in the laboratory the readings of the labels. The conditions of hygiene were poor, especially in supermarket freezers. Only 16 samples were labelled in accordance with current legislation. According to the results obtained, the products 'ethnic' distributed in the supermarkets visited, may be considered a potential risk to human health.

M. Prearo

2012-01-01

234

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

235

Relationship between horizontal hydroacoustic stock estimates and gillnet catches of surface-oriented fish in shallow Lake Balaton (Hungary Relation entre les estimations horizontales hydroacoustiques du stock et les captures au filet maillant de poissons de surface en eaux peu profondes du lac Balaton (Hongrie  

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. Nous avons examiné si les filets maillants et l’hydroacoustique fournissent des données comparables de la densité des poissons et des estimations de distribution en taille des poissons dans la couche d’eau supérieure d’un lac peu profond trouble et si l’inclusion de paramètres environnementaux et du stock de poissons pourrait améliorer la comparabilité des données entre les différents engins. Selon la pêche au filet maillant, la plupart des poissons de longueur totale inférieure à 14 cm étaient Alburnus alburnus, et la plupart des poissons de plus de 14 cm étaient Pelecus cultratus. Les distributions de taille et les tailles médianes obtenues à partir des filets maillants et de l’acoustique sont différentes. Les estimations dérivées de la seule densité acoustique ne représentaient que moins de 8,8?% de la variation des captures au filet maillant en nombre et aucune corrélation n’a été trouvée dans les indices de biomasse. La plupart des variations observées dans les captures par unité d’effort des filets maillants ont été associées à la transparence de l’eau, aucune des autres variables étudiées n’ont un important pouvoir explicatif. Nous concluons que la possibilité d’établir un modèle puissant décrivant la relation entre les estimations de la densité des poissons par pêche au filet maillant et de l’acoustique est faible dans les habitats peu profonds et troubles, et il ne pourrait être valable que si l’échantillonnage et les paramètres environnementaux affectant l’efficacité de capture des filets maillants et le post-traitement des données acoustiques sont considérés. Cette étude rappelle encore une fois que les filets maillants doivent être utilisés avec précaution pour analyser les tendances de l’abondance des poissons.

György Á.I.

2012-06-01

236

Rapid assessment of toxicity of oil sands process-affected waters using fish cell lines  

International Nuclear Information System (INIS)

Oil-sand process-affected waters (OSPAW) are being evaluated in acute and chronic toxicity tests with various model organisms to assess the safety of reclamation ponds where OSPAWs are being deposited. Classical toxicity assays typically require large volumes of test waters, take time and are costly. They may also require expensive analytical assays to characterize the contaminants present. Cytotoxicity assays using indigenous and model fish cell lines may prove useful for a prompt comparative toxicity assessment of copious samples retrieved at various temporal and spatial sites at a fraction of cost and time compared to in vivo assays. This presentation reported on a study in which a rapid fluorometric assay using several fish cell lines was used to assess the acute toxicity of 20 water samples including OSPAW. The water samples were mixed with media salts and evaluated directly on cells in culture without prior extraction procedures. The evaluation was done in blind and a consistent pattern of toxicity was observed with the tested cell lines. It was concluded that this approach may minimize the need of using whole organisms for toxicity assessment of OSPAW.

2008-10-05

237

Rapid assessment of toxicity of oil sands process-affected waters using fish cell lines  

Energy Technology Data Exchange (ETDEWEB)

Oil-sand process-affected waters (OSPAW) are being evaluated in acute and chronic toxicity tests with various model organisms to assess the safety of reclamation ponds where OSPAWs are being deposited. Classical toxicity assays typically require large volumes of test waters, take time and are costly. They may also require expensive analytical assays to characterize the contaminants present. Cytotoxicity assays using indigenous and model fish cell lines may prove useful for a prompt comparative toxicity assessment of copious samples retrieved at various temporal and spatial sites at a fraction of cost and time compared to in vivo assays. This presentation reported on a study in which a rapid fluorometric assay using several fish cell lines was used to assess the acute toxicity of 20 water samples including OSPAW. The water samples were mixed with media salts and evaluated directly on cells in culture without prior extraction procedures. The evaluation was done in blind and a consistent pattern of toxicity was observed with the tested cell lines. It was concluded that this approach may minimize the need of using whole organisms for toxicity assessment of OSPAW.

Sansom, B.; Dixon, D.G. [Waterloo Univ., Waterloo, ON (Canada); MacDonald, J.; Lee, L. [Wilfrid Laurier Univ., Waterloo, ON (Canada); MacKinnon, M. [Syncrude Canada Ltd., Edmonton, AB (Canada)

2009-07-01

238

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 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.

2010-04-15

239

Assessment of Present Anadromous Fish Production Facilities in the Columbia River Basin, US Fish and Wildlife 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 tabs.

Delarm, Michael R.; Smith, Robert Z.

1990-07-01

240

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

 
 
 
 
241

Extinction Risk and Overfishing: Reconciling Conservation and Fisheries Perspectives on the Status of Marine Fishes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Anthropogenic disturbances are ubiquitous in the ocean, but their impacts on marine species are hotly debated. We evaluated marine fish statuses using conservation (Red List threatened or not) and fisheries (above or below reference points) metrics, compared their alignment, and diagnosed why discrepancies arise. Whereas only 13.5% of Red Listed marine fishes (n = 2952) are threatened, 40% and 21% of populations with stock assessments (n = 166) currently are below their more conservative and ...

2012-01-01

242

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

243

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

1995-11-05

244

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

245

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

246

Assessing the feasibility of native fish reintroductions: a framework applied to threatened bull trout  

Science.gov (United States)

Translocations to recover native fishes have resulted in mixed success. One reason for the failure of these actions is inadequate assessments of their feasibility prior to implementation. Here, we provide a framework developed to assess the feasibility of one type of translocation-reintroduction. The framework was founded on two simple components of feasibility: the potential for recipient habitats to support a reintroduction and the potential of available donor populations to support a reintroduction. Within each component, we developed a series of key questions. The final assessment was based on a scoring system that incorporated consideration of uncertainty in available information. The result was a simple yet transparent system for assessing reintroduction feasibility that can be rapidly applied in practice. We applied this assessment framework to the potential reintroduction of threatened bull trout Salvelinus confluentus into the Clackamas River, Oregon. In this case, the assessment suggested that the degree of feasibility for reintroduction was high based on the potential of recipient habitats and available donor populations. The assessment did not provide a comprehensive treatment of all possible factors that would drive an actual decision to implement a reintroduction,

Dunham, Jason; Gallo, Kirsten; Shively, Dan; Allen, Chris; Goehring, Brad

2011-01-01

247

Dealing with uncertainty and heterogeneity in the assessment of structural and functional integrity in marine fish assemblages  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The increasing level of human pressure on marine ecosystems has led to higher awareness towards the need to understasnd the inter-connection of direct and indirect effects on communities and populations. Therefore, in the assessment of marine fish assemblages, there is an ongoing shift from monitoring the effect of fishing in exploited populations to analysing the effect of several impact sources on communities. This thesis contributes to the new methodological requirements of functional inte...

Pais, Miguel Pessanha Freitas Branco

2013-01-01

248

Biological assessments of Appalachian streams based on predictive models for fish, macroinvertebrate, and diatom assemblages  

Science.gov (United States)

We developed empirical models for fish, macroinvertebrate, and diatom assemblages to assess the biological condition of 268 streams sampled from 1993 to 2002 in 7 major river basins in the Appalachian region of the USA. These models estimate the expected taxonomic composition at each site based on observed variation in taxonomic composition at reference sites. The index, O/E, is the ratio of the number of predicted taxa that were observed (O) to that expected (E) to occur at a site and is a measure of taxonomic completeness. We compared how O/E for each assemblage varied among major landuse settings and whether impaired assemblages were associated with particular physicochemical conditions. We also examined concordance among assemblages in their response to stress. Biological, chemical, and physical data were collected following consistent protocols. We used land-cover criteria, published data, and topographic maps to classify sites by major landuse setting. Fish, macroinvertebrate, and diatom assemblages had been sampled at 73, 108, and 52, respectively, of the least disturbed sites used to establish reference conditions. The models accounted for a substantial portion of the natural variation in taxonomic composition across sites that was associated with biogeographic, climatic, and basin-scale factors and generally were unbiased across the range of environmental gradients observed in the region. Assessments at nonreference sites showed that impairment of fish and macroinvertebrate assemblages was most strongly associated with agriculture and urban land uses, whereas impairment of diatom assemblages was most strongly associated with mining in the basin. Concordance in assessments among assemblages was not strong. Assessments based on 2 assemblages differed in 28 to 57% of cases, and assessments were never concordant for cases where all 3 assemblages were sampled. Furthermore, only 1/2 of these cases would have been assessed as ecologically impaired had only 1 assemblage been sampled. Differences between observed and predicted frequencies of occurrence for individual taxa were generally consistent with known tolerances to environmental stressors and might aid in identifying causes of biological impairment. ?? 2008 by The North American Benthological Society.

Carlisle, D. M.; Hawkins, C. P.; Meador, M. R.; Potapova, M.; Falcone, J.

2008-01-01

249

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

250

Application of sensory and microbial analysis to assess quality of fish in Siliguri city of West Bengal, India.  

Science.gov (United States)

Sensory and certain microbial analyses were applied to assess the quality of raw fish sold at a market in Siliguri cityof West Bengal, India. In regular surveys undertaken during June to August 2008, a particular fish species was randomly selected, its source was noted and a sensory analysis, the quality index method (QIM) was applied to assess its quality Raw fish samples were also collected and a small quantity (about 1 g) of scales oran upper layer of the skin surface (forscale-less fish samples), gill, liverand a portion of gut with gut-contents were aseptically removed for enumeration of the total aerobic heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and coliform counts. Oreochromis mossambicus and Tenulosa ilisha recorded significantly higher QIM scores, compared to other species (pChanna punctatus scored the lowest QIM scores (0) while scores for Puntius ticto and Mystus vittatus and pond cultured species like Cirrhinus mrigala, Catla catla, Labeo rohita, Labeo bata and Cyprinus carpio were very marginal (p<0.05). Aeromonas spp., Salmonella spp. and total coliforms were recorded from all the studied species while Pseudomonas spp. was isolated from only seven species. Among the tissues examined, the lowest counts of total heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and total coliforms were recorded from the skin in every fish species. Highest counts of pathogenic bacteria (except Pseudomonas spp.) were recorded in Tenulosa ilisha for all the tissues except liver. Since fish are properly cooked in Bengali households, the risk of disease from fish consumption is relatively less. However, some tribes residing in the region are known to consume undercooked fish and proper cooking methods should be followed in view of the present findings to avoid health risks. Besides, utmost care should be taken while handling fish. PMID:21387907

Jha, Prithwiraj; Roy, Rudra Prasad; Barat, S

2010-09-01

251

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

252

Fish Breeding in Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available Fish breeding is a very important activity ensuring availability of fingerlings for the stocking of ponds, pens, tanks and cages. The breeding habits of fishes in nature differ from specie to specie Different species of fish choose different places in the aquatic environment for breeding. Most species do not breed when in captivity due to a number of factors. In Nigeria, induced breeding of African mud catfish through injection of ova prim hormone or pituitary gland is the main practice. This article reviews the wild sources of fish seeds, some cultivable fishes. carp breeding, relationship between the endocrine system and gonad development, function of the Central Nervous System (CNS in propagation, influence of ecological conditions on gonad development, artificial propagation of common carp, natural induced spawning, salmon culture and an innovation in the sea to educate fish breeders, fish genetics and fish culturist in other to facilitate their productivity.

J.A. Akankali

2011-06-01

253

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

254

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

255

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...

2006-01-01

256

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2010-05-15

257

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

258

Multibiomarker approach in Oreochromis mossambicus (Peters, 1892 fish to assess the impact of pollution in Mula River  

Directory of Open Access Journals (Sweden)

Full Text Available This article examines the advantages of the use of biomarkers as environmental indicators by applying it to Mula River, in Pune, which is in a critical environmental situation. We use a multi-biomarker approach in Oreochromis mossambicus fish as an integrated strategy to assess the impact of pollution. It comprehends a general biomarkers of fish immunity i.e. the respiratory burst activity, and specific biomarkers of contaminant exposure such as acetylcholinesterase (AChE activity and oxidative stress. Our results revealed different effects in the fish from polluted river water than control fish. Activities of antioxidative enzymes, phagocytic activity and neurotransmitter activity was significantly influenced (P < 0.05 in dose dependent manner. 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.

Dipti R. Gohil

2012-05-01

259

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

260

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 1973â??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

GÃ¥rdmark, Anna; Ã?stman, Ã?rjan

2012-01-01

 
 
 
 
261

Augmented Fish Health Monitoring for Washington Department of Wildlife, 1989 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

The augmented fish health monitoring project is funded by the Bonneville Power Administration (BPA) with the mandate to collect fish health data on anadromous fish stocks of the BPA Columbia River Basin in a standardized manner. The project began in 1986 and the data reported here was collected in the fourth year. This segment of the project was carried out by the Washington Department of Wildlife and summarizes fish health findings at anadromous game fish hatcheries in Washington State operated by the BPA. Information gathered to data 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 provide some indication of the impact of improving fish health on providing greater adult returns as well as an improved product for the fishery. 3 refs., 2 figs., 16 tabs.

Kerwin, John L.; Roberts, Steve; Oman, Leni; Bolding, Bruce

1991-04-01

262

Interrenal dysfunction in fish from contaminated sites: In vivo and in vitro assessment  

Energy Technology Data Exchange (ETDEWEB)

Cortisol, synthesized in the interrenal cells of teleost head kidney, has a major role in the physiologic response to physical and chemical stressors. Plasma levels of cortisol increase in physiologically competent fish acutely exposed to stressors such as cadmium or mercury. The effects of chronic low level exposures are less well understood. The author has diagnosed an endocrine impairment characterized by a reduced capacity to elevate plasma cortisol levels in response to an acute standardized capture stress in yellow perch (Perca flavescens) and in northern pike (Esox lucius) sampled at sites contaminated by mixtures of pollutants (heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls), by heavy metals, or by bleached kraft mill effluent. The studies with fish, as well as with amphibians at contaminated sites, demonstrated that low level chronic exposures impair secretion of corticosteroids. The author has developed new tests for assessment of the functional integrity of teleost and amphibian interrenal tissue using an adrenocorticotropic hormone (ACTH) challenge, in vivo and in vitro. The reduced ability to respond to ACTH indicates that the normal neuroendocrine response to stressors may be disrupted and that the ability to cope with biotic and abiotic stressors in the environment may be significantly reduced in the impaired animals.

Hontela, A. [Univ. du Quebec, Montreal, Quebec (Canada)

1998-01-01

263

Dredging of blue mussels ( Mytilus edulis L.) in a Danish sound: stock sizes and fishery-effects on mussel population dynamic  

DEFF Research Database (Denmark)

In April 1993, 1994 and 1995 the abundance of blue mussels, Mytilus edulis L., was estimated in Limfjorden, Denmark. The stocks were assessed by using a down-scaled model of a commercial mussel dredge which efficiency was analysed by comparing its samples with others collected by diver. The mean dredge efficiency was 17%. The fishing area in Limfjorden (700 km(2)) is divided into 22 fishery zones and mussel stock size was calculated for each zone. From April 1993 to April 1994 the total stock size declined from 771 000 to 616 000 t. In the same period, the exploitation rate in the fishery was 14% of the 1993 stock, and the size of mussel landings from each zone significantly correlated with their change in stock. In April 1995, the total mussel stock was reduced to 494 000 t. The mean exploitation rate in 1994-1995 was 15%. No correlation was observed between the size of mussel landings and the change in the mussel stock. In summer 1994, there was a long period of oxygen depletion in parts of Limfjorden. Thiscaused mortality of 33% of the mussels in the affected areas. In fishery zones without oxygen depletion a 46% increase in the mussel stocks was estimated. The massive loss of blue mussels caused by oxygen depletion exceeds the annual landings of mussels from the fishery. (C) 1999 Elsevier Science B.V. All rights reserved

Dolmer, Per; Kristensen, Per Sand

1999-01-01

264

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

265

Quality loss assessment in fish-based ready-to-eat foods during refrigerated storage  

Energy Technology Data Exchange (ETDEWEB)

The present research addresses the quality loss in two different ready-to-eat (RTE) sea foods. With this aim, chemical and microbiological parameters were measured in tuna lasagne (TL) and hake roe foods which were refrigerated (4 degree centigrade) for up to 35 and 71 days, respectively. Both foods showed a significant lipid oxidation (peroxide and interaction compound formation) development with storage time, which was especially marked in the case of the TL product, which also underwent an important lipid hydrolysis development. Both RTE products showed a low microbial development, no matter how much time had elapsed since the expiration dates; thus, low total viable count scores and volatile amine formation were attained while the presence of pathogen microorganisms was not detected. In view of the current increasing consumer demand for high quality refrigerated foods, the assessment of lipid damage related to nutritional and sensory values is recommended when fish-based RTE products are encountered. (Author) 46 refs.

Pourashouri, P.; Chapela, M. J.; Atanassova, M.; Cabado, A. G.; Vieites, J. M.; Aubourg, S. P.

2013-05-01

266

Assessing Cumulative Thermal Stress in Fish During Chronic Exposure to High Temperature  

Energy Technology Data Exchange (ETDEWEB)

As environmental laws become increasingly protective, and with possible future changes in global climate, thermal effects on aquatic resources are likely to receive increasing attention. Lethal temperatures for a variety of species have been determined for situations where temperatures rise rapidly resulting in lethal effects. However, less is known about the effects of chronic exposure to high (but not immediately lethal) temperatures and even less about stress accumulation during periods of fluctuating temperatures. In this paper we present a modeling framework for assessing cumulative thermal stress in fish. The model assumes that stress accumulation occurs above a threshold temperature at a rate depending on the degree to which the threshold is exceeded. The model also includes stress recovery (or alleviation) when temperatures drop below the threshold temperature as in systems with large daily variation. In addition to non-specific physiological stress, the model also simulates thermal effects on growth.

Bevelhimer, M.S.; Bennett, W.R.

1999-11-14

267

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...

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

2010-01-01

268

Rapid assessment of the toxicity of oil sands process-affected waters using fish cell lines.  

Science.gov (United States)

Rapid and reliable toxicity assessment of oil sands process-affected waters (OSPW) is needed to support oil sands reclamation projects. Conventional toxicity tests using whole animals are relatively slow, costly, and often subjective, while at the same time requiring the sacrifice of test organisms as is the case with lethal dosage/concentration assays. A nonlethal alternative, using fish cell lines, has been developed for its potential use in supporting oil sands reclamation planning and to help predict the viability of aquatic reclamation models such as end-pit lakes. This study employed six fish cell lines (WF-2, GFSk-S1, RTL-W1, RTgill-W1, FHML, FHMT) in 24 h viability assays for rapid fluorometric assessment of cellular integrity and functionality. Forty-nine test water samples collected from the surface of oil sands developments in the Athabasca Oil Sands deposit, north of Fort McMurray, Alberta, Canada, were evaluated in blind. Small subsample volumes (8 ml) were mixed with 2 ml of 5× concentrated exposure media and used for direct cell exposures. All cell line responses in terms of viability as measured by Alamar blue assay, correlated well with the naphthenic acids (NA) content in the samples (R (2) between 0.4519 and 0.6171; p<0.0001) when data comparisons were performed after the bioassays. NA or total acid-extractable organics group has been shown to be responsible for most of the acute toxicity of OSPW and our results further corroborate this. The multifish cell line bioassay provides a strong degree of reproducibility among tested cell lines and good relative sensitivity of the cell line bioassay as compared to available in vivo data that could lead to cost effective, high-throughput screening assays. PMID:23263937

Sansom, Bryan; Vo, Nguyen T K; Kavanagh, Richard; Hanner, Robert; Mackinnon, Michael; Dixon, D George; Lee, Lucy E J

2013-01-01

269

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

270

Exposure of fish to biologically treated bleached-kraft mill effluent; 3: Fish habitat and population assessment  

Energy Technology Data Exchange (ETDEWEB)

Populations of mountain whitefish (Prosopium williamsoni) and longnose sucker (Catostomus catostomus) exposed to bleached-kraft mill effluent (BKME) in the Wapiti/Smoky river system in northwestern Alberta were compared to similar populations in a reference river system (the upper North Saskatchewan River) Fish species distribution and relative abundance patterns were linked to natural events such as floods and low flows, and to habitat quality. There was no evidence that fish were avoiding the effluent plume area; relative abundance was often highest near the effluent discharge due to use of this area for overwintering and rearing. Radiotelemetry and recapture studies indicated that fish movements could be both rapid and extensive, occurring during spawning periods and at other times of the year. Thus, exposure could not be assumed to be related to capture location alone; separate exposure measures were necessary. Populations of exposed mountain whitefish and longnose sucker were growing and reproducing successfully. Higher condition factors in exposed longnose suckers and greater mesenteric fat stores in exposed individuals of both species were not accompanied by any apparent disruption in allocation of energy to reproduction or growth. The age structure of the populations showed that there had been no losses of age classes through reproductive or recruitment failures, and growth curves were indistinguishable from reference curves. There were no correlations between indicators of exposure and population-level effects. Important natural phenomena, including a one-hundred-year flood and natural upstream/downstream habitat gradients, affected species distribution and were correlated with some population parameters such as condition factors and relative gonad size.

Swanson, S.M. (Golder Associates Ltd., Calgary, Alberta (Canada)); Schryer, R. (SENTAR Consultants Ltd., Saskatoon, Saskatchewan (Canada)); Shelast, R. (SENTAR Consultants Ltd., Calgary, Alberta (Canada)); Kloepper-Sams, P.J.; Owens, J.W. (Procter Gamble Products, Cincinnati, OH (United States))

1994-09-01

271

Assessing the health condition profile in the freshwater fish Astyanax aeneus in Champoton River, Mexico.  

Science.gov (United States)

The use of biomarkers for monitoring aquatic environmental quality has gained considerable interest worldwide. The effects of the environmental conditions of Río Champotón, México, in the hotspot of Mesoamerica, were assessed in Astyanax aeneus, a native fish of the tropics of southwestern México. Pollution from agrochemical residues is a major problem in Río Champotón. Three study sites along the freshwater portion of the river were monitored in April, July, and November 2007 and February 2008. This study includes a water quality index, a set of biomarkers (hepatic glycogen levels and lipid peroxidation in liver, gills, and muscle) to assess the integrated biomarker response, and population bioindicators (gonadosomatic and hepatosomatic indices and Fulton's condition factor). Although the water quality index suggested low level of contamination in the Río Champotón, biomarkers indicated that A. aeneus is exposed to stressors that impair biological responses. The integrated biomarker response showed stress periods with higher biomarker response and recovery periods with decreasing biomarker values. The somatic indices did not indicate severe effects at the population level. This study illustrates the usefulness of lipid peroxidation evaluation in the assessment of aquatic health conditions and corroborates the suitability of A. aeneus as a sentinel species. PMID:24579529

Trujillo-Jiménez, Patricia; Sedeño-Díaz, Jacinto Elías; López-López, Eugenia

2014-01-01

272

Automated quantification of FISH signals in urinary cells enables the assessment of chromosomal aberration patterns characteristic for bladder cancer.  

Science.gov (United States)

Targeting the centromeres of chromosomes 3, 7, 17 (CEP3, 7, 17) and the 9p21-locus (LSI9p21) for diagnosing bladder cancer (BC) is time- and cost-intensive and requires a manual investigation of the sample by a well-trained investigator thus overall limiting its use in clinical diagnostics and large-scaled epidemiological studies. Here we introduce a new computer-assisted FISH spot analysis tool enabling an automated, objective and quantitative assessment of FISH patterns in the urinary sediment. Utilizing a controllable microscope workstation, the microscope software Scan^R was programmed to allow automatic batch-scanning of up to 32 samples and identifying quadruple FISH signals in DAPI-scanned nuclei of urinary sediments. The assay allowed a time- and cost-efficient, automated and objective assessment of CEP3, 7 and 17 FISH signals and facilitated the quantification of nuclei harboring specific FISH patterns in all cells of the urinary sediment. To explore the diagnostic capability of the developed tool, we analyzed the abundance of 51 different FISH patterns in a pilot set of urine specimens from 14 patients with BC and 21 population controls (PC). Herein, the results of the fully automated approach yielded a high degree of conformity when compared to those obtained by an expert-guided re-evaluation of archived scans. The best cancer-identifying pattern was characterized by a concurrent gain of CEP3, 7 and 17. Overall, our automated analysis refines current FISH protocols and encourages its use to establish reliable diagnostic cutoffs in future large-scale studies with well-characterized specimens-collectives. PMID:24802410

Köhler, Christina U; Martin, Laura; Bonberg, Nadine; Behrens, Thomas; Deix, Thomas; Braun, Katharina; Noldus, Joachim; Jöckel, Karl-Heinz; Erbel, Raimund; Sommerer, Florian; Tannapfel, Andrea; Harth, Volker; Käfferlein, Heiko U; Brüning, Thomas

2014-06-13

273

Field and laboratory investigations to assess impacts to fish health from oil sands wastewater releases (Part 1)  

International Nuclear Information System (INIS)

A combined field and laboratory investigation was conducted during 1995 to evaluate the health of fish which were exposed to wastewaters from Suncor Inc., Oil Sands Group's operation. This investigation was designed to: assess effects on major trophic components of aquatic ecosystems; assess effects on the general condition and health of fish; and relate chemical characteristics to measured responses. A suite of indicators was examined at several levels of biological organization: biochemical, physiological, whole-organisms, population and community. This comprehensive approach was followed because stress effects on fish cannot be adequately evaluated by measuring a single indicator at a single level of organization. Fish health data for walleye (Stizostedion vitreum), goldeye (Hiodon alosoides) and longnose sucker (Catostomus catostomus) showed that there were no adverse effects on fish health at any level of organization. The laboratory investigations comprised 7 and 28 exposures to wastewater and showed that no observed effect levels (NOELs) and lowest observed effect levels (LOELs) were greater than 10% for biochemical and physiological and whole-organism endpoints

1996-11-17

274

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

275

A size-based probabilistic assessment of PCB exposure from Lake Michigan fish consumption  

Energy Technology Data Exchange (ETDEWEB)

The state of Wisconsin has recently issued a fish consumption advisory that includes suggested consumption rates for Lake Michigan fish, based on fish size and PCB concentration. To evaluate the size-based exposure risk from Lake Michigan fish consumption, the authors estimated PCB exposure probabilities for five Lake Michigan fish species using two Bayesian models. The models confirm that very few individuals of any of the five species are likely to have PCB concentrations low enough to fall into the category in which consumption is unrestricted. Among smaller fish (<50 cm), brown trout have the highest PCB levels, while lake trout are the most contaminated among larger fish (>60 cm). Eating meals from multiple individuals of some species results in a high probability that at least one of the meals will exceed 1.9 mg/kg, the upper PCB concentration recommended for consumption in the advisory.

Stow, C.A. [Duke Univ., Durham, NC (United States). Nicholas School of the Environment; Qian, S.S. [Portland State Univ., OR (United States)

1998-08-01

276

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Francisco Arreguín-Sánchez; Soli?s -rami?rez, Manuel J.; Gonza?lez La Rosa, Mari?a E.

2000-01-01

277

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

278

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 tabs

1989-04-12

279

Stock-based vs. fleet-based evaluation of the multi-annual management plan for the cod stocks in the Baltic Sea  

DEFF Research Database (Denmark)

This study evaluated the EU 2008 multi-annual plan for Baltic cod stock recovery. The plan combines harvest control rules that set TACs with reductions in direct effort (E) and fishing mortality (F). Performance and robustness of the plan are tested with a management strategy evaluation model (MSE). Stochastic simulations are carried out under different scenarios of recruitment and sources of uncertainties. Under the different magnitudes of errors investigated, the plan in its current design is likely to reach precautionary targets for the Eastern and the Western Baltic cod stocks by 2015. It is, however, more sensitive to implementation errors (e.g. catch misreporting) than to observation errors (e.g. data collection) when the (i) current settings of the ICES single-stock assessment model are maintained. (ii) intended fishing effort reduction is fully complied with, and (iii) biological parameters are assumed constant. For the Eastern Baltic stock, additional sources of uncertainties from fishery adaptation to the plan are tested using a fleet-based and spatially explicit version of the model which leads to higher reductions in F and no significant change in management robustness. The relative difference between both approaches is mainly due to differences in exploitation patterns in catching the same amount of fish. The effort control is demonstrated to be more efficient when supplemented with a TAC and avoids un-intended effects from fishery responses, e.g. spatial effort reallocation. Medium term economic evaluation of fishery performance shows an initial reduction in profit with effort and TAC reductions, but profit is always positive. (C) 2009 Elsevier B.V. All rights reserved.

Bastardie, Francois; Vinther, Morten

2010-01-01

280

Assessing relationships between chemical exposure, parasite infection, fish health, and fish ecological status: a case study using chub (Leuciscus cephalus) in the Bílina River, Czech Republic.  

Science.gov (United States)

Multiple stressor scenarios, as they are relevant in many watersheds, call for approaches extending beyond conventional chemical-focused approaches. The present study, investigated the fish population, represented by chub (Leuciscus cephalus), in the Bílina River (Czech Republic), which is impacted by various pollution sources and might pose a risk on the fish population. To confirm or reject this hypothesis it was examined whether there exists an association between abundance of chub and exposure to toxic chemicals as well as natural stressors, represented by parasites, and whether health-related suborganismal traits, namely, organ indices, tissue histopathology, and immune parameters, would help in revealing relationships between stressor impact and population status. Toxic pressure was assessed by the toxic unit approach, which gives an integrative estimate of toxic effect concentrations and by measuring the biomarkers cytochrome P4501A and vitellogenin, which indicate exposure to bioavailable arylhydrocarbon- or estrogen receptor ligands. Parasite pressure was estimated by determining abundance and species composition of ecto- and endoparasites of chub. Chub abundance was high upstream in the Bílina, low to zero in the middle stretches, and increased again downstream. Toxic pressure increased in the downstream direction, while parasite intensity decreased in this direction. Health status of chub did not differ clearly between up-, middle-, and downstream sites. Thus, it appears that neither toxic pressure nor parasite pressure nor their combination translates into a change of chub health status. By using varied assessment tools, this study provides evidence against a presumed causative role of toxicants impairing the fish ecological status of the Bílina River. PMID:20821465

Wenger, Michael; Ondracková, Markéta; Machala, Miroslav; Neca, Jirí; Hyrsl, Pavel; Simková, Andrea; Jurajda, Pavel; von der Ohe, Peter; Segner, Helmut

2010-02-01

 
 
 
 
281

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

282

Exposure assessment of pregnant Portuguese women to methylmercury through the ingestion of fish: cross-sectional survey and biomarker validation.  

Science.gov (United States)

Methylmercury (MeHg) contamination is a critical public health problem in Portugal, where fish is an important component of the daily diet. The Portuguese are the third largest consumers in the world (after Japan and Iceland) but first in Europe. Prenatal exposure to MeHg is believed to be linked to fetal/child neurodevelopment and behavioral impairments due to the neurotoxicity of the compound. The objective of this study was to assess the exposure of pregnant Portuguese women to mercury (Hg) due to fish consumption, calculating the indices of risk and confirming exposure through analyses of a biomarker of exposure. The study consisted of a cross-sectional evaluation of 343 pregnant women recruited at their visit to two antenatal care units in Lisbon, Portugal. A food frequency questionnaire was used to estimate prenatal exposure. Total Hg levels in hair were analyzed by atomic absorption, in samples from 186 women. The average fish consumption was 3.1 meals per week. Median Hg level in the hair was 1.26 ?g/g (range: 0.07-5.3 ?g/g). The mean calculated risk index was 0.81; however, 28% of the pregnant women ingested levels above the provisional tolerable weekly intake (PTWI) level recommended by the World Health Organization (WHO; 1.6 mg/kg per body weight), indicating the possibility of risk due to MeHg exposure. Multiple linear regression analysis showed the risk index was reliably predicted from predatory fish species and number of fish meals consumed per week. Ingestion of black and silver scabbard fish as well as mixed predatory fish cooked in traditional dishes enhanced the toxicity risk. In conclusion, some exposure levels exceeded the reference value; therefore, nutritional counseling needs to be provided to populations at risk. PMID:24555654

Nunes, Elisabete; Cavaco, Afonso; Carvalho, Cristina

2014-01-01

283

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...

2012-01-01

284

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)

2000-10-01

285

ENVIRONMENT AGENCY BROWN TROUT STOCKING REVIEW 2007/8  

…research (listed in Appendix III on page 19) demonstrated no apparent impact of stocked fish on wild fish from competition or predation. However, the peer review of over 300 papers across Europe concluded that hybridisation poses a risk that the offspring have a lower ability to survive and reproduce successfully…

286

Influences of large- and regional-scale climate on fish recruitment in the Skagerrak–Kattegat over the last century  

Science.gov (United States)

Dynamics of commercial fish stocks are generally associated with fishing pressure and climate variability. Due to short time series, past studies of the relationships between fish stock dynamics and climate have mainly been restricted to the last few decades. Here we analyzed a century-long time series of plaice, cod and haddock from the Skagerrak-Kattegat, to assess the long-term influence of climate on recruitment. Recruitment success (RS) was compared against sea-surface temperature (SST) and atmospheric circulation indices on large (North Atlantic) and regional (Skagerrak-Kattegat) scales. Our results show that the influence of climate on RS was more pronounced on longer, than on shorter timescales. Over the century-long period, a shift from low to high climate sensitivity was seen from the early to the late part for plaice and cod, while the opposite was found for haddock. This shift suggests that the increasing fishing pressure and the climate change in the Skagerrak-Kattegat have resulted in an increased sensitivity of RS to climate for plaice and cod. The diminishing of climate sensitivity in haddock RS, on the other hand, may be linked to the early twentieth century collapse of the stock in the region. While no long-term relationship between RS and the Atlantic Multidecadal Oscillation (AMO) could be found, large RS fluctuations during the positive phase of the AMO (1935-1960), relative to the cold phases, suggests a changed pattern in recruitment during warm periods. On the other hand, this could be due to the increased fishing pressure in the area. Thus, reported correlations between climate and fish may be caused by strong trends in climate in the late-twentieth century, and coincident reduction in fish stocks caused by intense fishing, rather than a stable relationship between climate and fish recruitment per se.

Linderholm, Hans W.; Cardinale, Massimiliano; Bartolino, Valerio; Chen, Deliang; Ou, Tinghai; Svedäng, Henrik

2014-06-01

287

Estimating the long-term effects of stocking domesticated trout into wild brown trout ( Salmo trutta ) populations : an approach using microsatellite DNA analysis of historical and contemporary samples  

DEFF Research Database (Denmark)

Indigenous salmonid fish gene pools are affected by domesticated conspecifics, derived from aquaculture escapes and deliberate releases. Variability was examined at nine microsatellite loci in order to assess the long-term impact of stocking domesticated trout in two brown trout populations. The study was based on analysis of two historical samples (194556), represented by old scale collections, and seven contemporary samples (1986-2000). In one population historical and contemporary samples were remarkably genetically similar despite more than a decade of intense stocking. Estimation of admixture proportions showed a small genetic contribution from domesticated trout (approximately 6%), and individual admixture analysis demonstrated a majority of nonadmixed individuals. The expected genetic contribution by domesticated trout was 64%, assessed from the number of stocked trout and assuming equal survival and reproductive performance of wild and domesticated trout. This demonstrates poor performance and low fitness of domesticated trout in the wild. In another population there was a strong genetic contribution from domesticated trout (between 57% and 88% in different samples), both in samples from a broodstock thought to represent the indigenous population and in a sample of wild spawners. Survival of domesticated trout and admixture with indigenous fish in the broodstock and subsequent stocking into the river, combined with a low population size of native trout relative to the number of stocked trout, could explain the observed introgression. Few nonadmixed individuals remained in the introgressed population, and I discuss how individual admixture analysis can be used to identify and conserve nonintrogressed remains of the population.

Hansen, Michael Møller

2002-01-01

288

NC 060 Coarse Fish/English  

…book describe how important it is to have different types of habitat to support successful fish populations. They concentrate on the creation of the right habitats to support fish. (Some types of fish stock are intensively managed to be greater than their ecosystem would normally support, often in purpose…

289

Effects of Short-Term Holding on Fishes: A Synthesis and Review. Volume 29 Tracy Fish Facilities Study.  

Science.gov (United States)

Collecting, handling, sorting, holding, and transportation in aquaculture, stocking programs, fish salvage, and commercial and sport fisheries can be stressful to the affected fishes. Stress-related effects of short-term holding are influenced by water qu...

C. M. Woodley C. R. Liston D. E. Portz J. J. Cech

2005-01-01

290

Asymmetric Effects in Emerging Stock Markets - The Case of Iran Stock Market  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In view of the mixed empirical results in the literature, this paper assesses the extent of asymmetric volatility effects in the Iranian stock market as an emerging stock market, using a variety of nonlinear autoregressive conditional heteroskedasticity specifications. Tests based on standardized residuals from a fitted GARCH model suggest a lack of asymmetric effects in the dynamic volatility of the Iranian stock market. Empirical analyses with asymmetric GARCH models also reject th...

Seyyed Ali Paytakhti Oskooe; Ali Shamsavari

2011-01-01

291

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 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

292

Assessing connectivity in coastal systems as a tool for fish management and conservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Connectivity is a critical component of marine fish populations as it drives population replenishment, determines colonization patterns and populations’ resilience to harvest. Knowledge of individual movement patterns is pivotal to ascertain population dynamics and underpins sustainable management. Many marine fish species occupy spatially segregated habitats throughout their life history. Estuarine nursery function and the ecological link between estuaries and the coastal environment were ...

Santos, Patrick Reis

2013-01-01

293

{sup 137}Cs in fishes and water in Finnish lakes - considerations for radioecological risk assessment  

Energy Technology Data Exchange (ETDEWEB)

Most of Finnish lakes are oligo-trophic and hence accumulation of {sup 137}Cs in fishes is high. Besides fishes from several lakes annually since 1986, water samples from about 20 lakes in 1998 and 2002 were analysed for {sup 137}Cs. In water of most lakes {sup 137}Cs decreased by 10 to 40% from 1998 to 2002, but there were some lakes where {sup 137}Cs increased by 20% from 1998 to 2002. Variation ranges in activity concentrations of {sup 137}Cs in fishes and also in lake waters were still large although sixteen years had elapsed since the deposition. Correlation of {sup 137}Cs in lake water with the original level of the deposited {sup 137}Cs was good for most of the lakes, but not for all of them. Although fishes get {sup 137}Cs mainly via food, correlation of {sup 137}Cs in fishes with that in lake water was amazingly good based on the results from 1998-2002. Ecological half times of {sup 137}Cs in various lakes and in various fish species since 1986, as well as lake specific concentration factors in 1998-2002 will be determined. Since activity concentrations of {sup 137}Cs in fishes remain high in freshwater ecosystem for a long time after deposition, it results in long-term exposure of fishes and other biota in that ecosystem. (author)

Saxen, R.; Koskelainen, U. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

2004-07-01

294

PREVALENCE OF ESCHERICHIA COLI IN FOOD FISHES ASSESSED FROM DOMESTIC RETAIL FISH MARKET, GUNTUR CITY, ANDHRA PRADESH, INDIA: A CASE STUDY  

Directory of Open Access Journals (Sweden)

Full Text Available The prevalence of Escherichia coli in fin fish and shell fish samples collected from domestic retail fish market, Guntur City, Andhra Pradesh, India. Domestic fish markets in India are poorly maintained hygienic conditions and are prone to several microbiological pathogens which in turn lead to spread of food safety illness such asdiarrhea etc. Most of the low income group people access their food fishes from the local fish markets. Studied over a period of one Year (November 2009 - December 2010. Of the different freshwater, brakishwater, marinewater fin fishes and shell fishes were analyzed, the highest incidence of Escherichia coli was seen in freshwater fishes, (79.76% followed by the brakishwater fishes (78.84%. Among the crustaceans (95.2% showed the highest incidence followed by Macrobrachium rosenbargii (54.16%. Both fin fishes and crustaceans the incidence of Escherichia coli was seen in crustaceans. A well marked seasonal variation in the incidence pattern was observed in both fin fishes and crustaceans with higher incidence during monsoon season fallowed by post-monsoon and pre-monsoon. Results were revealed that the E.coli loads remained higher in Macrobrachium rosenbargii than other finfish and shellfishes. The fishes were contaminated with E.coli indicating poor hygiene and sanitary condition in domestic fish market. The percentages of the prevallance of E.coli were compared to seasonal variation highest in monsoon.

BUJJAMMA POLIMETLA

2013-07-01

295

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

296

Are the Most Plastic Species the Most Abundant Ones? An Assessment Using a Fish Assemblage  

Science.gov (United States)

Few studies have evaluated phenotypic plasticity at the community level, considering, for example, plastic responses in an entire species assemblage. In addition, none of these studies have addressed the relationship between phenotypic plasticity and community structure. Within this context, here we assessed the magnitude of seasonal changes in digestive traits (seasonal flexibility), and of changes during short-term fasting (flexibility during fasting), occurring in an entire fish assemblage, comprising ten species, four trophic levels, and a 37-fold range in body mass. In addition, we analyzed the relationship between estimates of digestive flexibility and three basic assemblage structure attributes, i.e., species trophic position, body size, and relative abundance. We found that: (1) Seasonal digestive flexibility was not related with species trophic position or with body size; (2) Digestive flexibility during fasting tended to be inversely correlated with body size, as expected from scaling relationships; (3) Digestive flexibility, both seasonal and during fasting, was positively correlated with species relative abundance. In conclusion, the present study identified two trends in digestive flexibility in relation to assemblage structure, which represents an encouraging departure point in the search of general patterns in phenotypic plasticity at the local community scale.

Vidal, Nicolas; Zaldua, Natalia; D'Anatro, Alejandro; Naya, Daniel E.

2014-01-01

297

Fish acute toxicity syndromes and their use in the QSAR approach to hazard assessment  

Energy Technology Data Exchange (ETDEWEB)

Implementation of the Toxic Substances Control Act of 1977 creates the need to reliably establish testing priorities because laboratory resources are limited and the number of industrial chemicals requiring evaluation is overwhelming. The use of quantitative structure activity relationship (QSAR) models as rapid and predictive screening tools to select more potentially hazardous chemicals for in-depth laboratory evaluation has been proposed. Further implementation and refinement of quantitative structure-toxicity relationships in aqueous toxicology and hazard assessment requires the development of a mode-of-action database. With such a database, a qualitative structure-activity relationship can be formulated to assign the proper mode of action, and respective QSAR, to a given chemical structure. In this review, the development of fish acute toxicity syndromes (FATS), which are toxic-response sets based on various behavioral and physiological-biochemical measurements, and their projected use in the mode-of-action database are outlined. Using behavioral parameters monitored in the fathead minnow during acute toxicity testing, FATS associated with acetylcholinesterase (AChE) inhibitors and narcotics could be reliably predicted. However, compounds classified as oxidative phosphorylation uncouplers or stimulants could not be resolved. Refinement of this approach by using respiratory-cardiovascular responses in the rainbow trout, enabled FATS associated with AChE inhibitors, convulsants, narcotics, respiratory blockers, respiratory membrane irritants, and uncouplers to be correctly predicted.

McKim, J.M.; Bradbury, S.P.; Niemi, G.J.

1987-04-01

298

Essays on performance-vested stock options and corporate governance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This doctorate project aims to assess the incentive effect of performance-vested stock option (PVSO) in the context of corporate governance and to examine the role of corpo¬rate governance in determining the presence and the level of PVSO awards. We find that performance-vested stock options, conditioning the vesting of stock options on pre¬determined performance target which are generally set rela¬tive to the industry median or peer group, can outperform traditional stock options by bette...

Bo Qin,

2010-01-01

299

Cartilaginous fishes along the North-Norwegian coast. Distributions and densities with regard to fishing and sea temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Scientists are becoming increasing aware that many of the world’s cartilaginous fish stocks are particularly vulnerable to overexploitation by modern fishing activities. Very little is known about the cartilaginous fish stocks found in the North Norwegian coastal area. In other areas some of these species have been severely depleted by fishing. The aim of this study was to broaden the knowledge these species within this area and determine what factors play an important role in controlling t...

Williams, Tom

2007-01-01

300

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 reservoirs. Alternatively, necrosis occurred more in fish from the river. Fish gill anomalies in both species did not differ between the two reservoirs, despite having different water quality. We rejected the hypothesis that reservoirs with lower water quality have fish with more gill injuries compared with high water quality reservoirs. Moreover, the eutrophic river seems to affect differently the healthy condition of fish species, compared with the eutrophic reservoir. PMID:21956340

Gomes, Iracema David; Nascimento, Aparecida A; Sales, Armando; Araújo, Francisco Gerson

2012-09-01

 
 
 
 
301

Estuarine fish health assessment: Evidence of wastewater impacts based on nitrogen isotopes and histopathology  

Energy Technology Data Exchange (ETDEWEB)

Sewage effluent is a powerful agent of ecological change in estuaries. While the effects of sewage pollution on water quality are usually well documented, biological responses of exposed organisms are not. We quantified health impacts in the form of pathological tissue changes across multiple organs in estuarine fish exposed to elevated levels of treated wastewater. Structural pathologies were compared in wild populations of four fish species from two subtropical estuaries on the east coast of Australia that differ substantially in the amount of direct wastewater loadings. Uptake of sewage-derived nitrogen by fish was traced with stable nitrogen isotopes. Pathologies were common in the liver, spleen, gill, kidney and muscle tissues, and included granulomas, melanomacrophage aggregates, and multiple deformities of the gill epithelia. Tissue deformities were more frequent in fish exposed directly to wastewater discharges. Mullet (Valamugil georgii) were most affected, with only a single specimen free of pathologies in the sewage-impacted estuary. Similarly, in those fish that had structural abnormalities, more deformities were generally found in individuals from sites receiving sewage. These spatial contrasts in impaired fish health correspond to significantly enriched {delta}{sup 15}N values in fish muscle as a consequence of fish assimilating sewage-N. Overall, the pattern of lower health and enriched {delta}{sup 15}N values in fish from sewage-impacted areas suggests that organism health is lowered by sewage inputs to estuaries. Measurements of organism health are required to understand the effects of sewage on estuarine ecosystems, and histopathology of fishes is a powerful tool to achieve this.

Schlacher, Thomas A. [Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore DC, QLD 4558 (Australia)], E-mail: tschlach@usc.edu.au; Mondon, Julie A. [School of Life and Environmental Sciences, Deakin University, Warrnambool (Australia)], E-mail: julie.mondon@deakin.edu.au; Connolly, Rod M. [Australian Rivers Institute - Coast and Estuaries and Griffith School of Environment, Griffith University (Australia)], E-mail: r.connolly@griffith.edu.au

2007-11-15

302

Dispersal, growth and diet of stocked and wild northern pike fry in a shallow natural lake, with implications for management of stocking programs  

DEFF Research Database (Denmark)

Increasing evidence suggests that stocking northern pike Esox lucius has had limited success, especially when age-0 fish are stocked into water bodies where the recruitment of northern pike already occurs. To better understand the ecology of wild and stocked fry, we investigated the dispersal, growth, and food composition of advanced pike fry (â?¼30 mm) stocked at a high density at a common release site in a shallow natural lake that contained wild youngof- the-year (age-0) pike. The stocked pike fry colonized the entire lake shoreline within just a few days. Dispersal was inversely related to size at stocking, suggesting that smaller fish were displaced by competitively superior larger individuals. While the stocked pike were initially larger than the wild age-0 pike, suboptimal growth was evident among the stocked pike and they were smaller than the wild ones at the end of the growing season. Stomach analyses revealed that the stocked pike ingested less diverse prey items and had higher fractions of empty stomachs throughout the study period. Overall, the fraction of stocked pike in samples rapidly declined over the season, which may have been caused by differential survival or immigration into or emigration out of the study system. Our study adds to the existing literature suggesting that the stocking of age-0 northern pike into waters with naturally reproducing pike populations will result in limited success. We propose two potentially complementary explanations for the apparent low fitness of stocked individuals in competition with wild conspecifics: (1) genetic-based local maladaptation among the stocked fish and (2) carryover effects from the hatchery. The latter may be less likely because the fry stocked were the offspring of wild fish and only spent a few weeks in the hatchery

Skov, Christian; Koed, Anders

2011-01-01

303

Dispersal, growth, and diet of stocked and wild northern pike fry in a shallow natural lake, with implications for the management of stocking programs  

DEFF Research Database (Denmark)

Increasing evidence suggests that stocking northern pike Esox lucius has had limited success, especially when age-0 fish are stocked into water bodies where the recruitment of northern pike already occurs. To better understand the ecology of wild and stocked fry, we investigated the dispersal, growth, and food composition of advanced pike fry (similar to 30 mm) stocked at a high density at a common release site in a shallow natural lake that contained wild young-of- the-year (age-0) pike. The stocked pike fry colonized the entire lake shoreline within just a few days. Dispersal was inversely related to size at stocking, suggesting that smaller fish were displaced by competitively superior larger individuals. While the stocked pike were initially larger than the wild age-0 pike, suboptimal growth was evident among the stocked pike and they were smaller than the wild ones at the end of the growing season. Stomach analyses revealed that the stocked pike ingested less diverse prey items and had higher fractions of empty stomachs throughout the study period. Overall, the fraction of stocked pike in samples rapidly declined over the season, which may have been caused by differential survival or immigration into or emigration out of the study system. Our study adds to the existing literature suggesting that the stocking of age-0 northern pike into waters with naturally reproducing pike populations will result in limited success. We propose two potentially complementary explanations for the apparent low fitness of stocked individuals in competition with wild conspecifics: (1) genetic-based local maladaptation among the stocked fish and (2) carryover effects from the hatchery. The latter may be less likely because the fry stocked were the offspring of wild fish and only spent a few weeks in the hatchery.

Skov, Christian Houlberg; Koed, Anders

2011-01-01

304

Contents and risk assessment of heavy metals in marine invertebrates from Korean coastal fish markets.  

Science.gov (United States)

The concentrations of the heavy metals cadmium (Cd), mercury (Hg), lead (Pb), chromium, silver, nickel, copper, and zinc in the edible portions of 105 marine invertebrates representing 16 mollusk and crustacean species were accurately determined to evaluate their hazard for human consumption. The samples were collected in 2011 from major fish markets on the coast of Korea and analyzed for Hg using a direct Hg analyzer and for other metals using inductively coupled plasma mass spectrometry. Estimated dietary exposure (EDE) was determined, and a risk assessment was made of the heavy metals to provide information concerning consumer safety. The Cd concentrations, which were the highest for the three hazardous metals (Cd, Hg, and Pb), were significantly higher (P Food Additives or the U.S. Environmental Protection Agency. The EDE of Cd, Hg, and Pb for each class of marine invertebrate were 0.07 to 2.64, 0.01 to 0.43, and 0.001 to 0.16% of the PTDI, respectively. The total EDE of Cd, Hg, and Pb for marine invertebrates accounted for 4.03, 0.96, and 0.21%, respectively, of the PTDI. The EDE of other metals in each class of marine invertebrate was less than 2% of the PTDI. The hazard index is a reasonable parameter for assessing the risk of heavy metal consumption associated with contaminated food. In the present study, the hazard index for all of the species was less than 1.0, which indicates that the intake of heavy metals from consumption of these marine invertebrates does not represent an appreciable hazard to humans. PMID:24853529

Mok, Jong Soo; Kwon, Ji Young; Son, Kwang Tae; Choi, Woo Seok; Kang, Sung Rim; Ha, Na Young; Jo, Mi Ra; Kim, Ji Hoe

2014-06-01

305

Assessment of committed effective dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)  

International Nuclear Information System (INIS)

An assessment of committed effective dose (CED) due to consumption of Red Sea fish containing ''2''1''0Po and ''1''3''7Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of 2''1''0Po were found in the ranges 0.25-6.42 (carnivores), 0.7- 5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weigh, which were several times lower than those of ''2''1''0Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (?Sv/Yr) in carnivores, omnivores and herbivores, respectively, for ''1'''3''7Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For ''2''1''0Po, it was found to be 3.47, 4.81and 4.14 (?Sv/Yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish ). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of ''1''3''7Cs is negligible compared to ''2''1''0Po.(Author)

2008-01-01

306

Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)  

International Nuclear Information System (INIS)

An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing 210Po and 137Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of 210Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of 210Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (?Sv/yr) in carnivores, omnivores and herbivores, respectively, for 137Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For 210Po, it was found to be 3.47, 4.81 and 4.14 (?Sv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of 137Cs is negligible compared to 210Po

2008-04-15

307

Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)  

Energy Technology Data Exchange (ETDEWEB)

An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing {sup 210}Po and {sup 137}Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of {sup 210}Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of {sup 210}Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 ({mu}Sv/yr) in carnivores, omnivores and herbivores, respectively, for {sup 137}Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For {sup 210}Po, it was found to be 3.47, 4.81 and 4.14 ({mu}Sv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of {sup 137}Cs is negligible compared to {sup 210}Po.

Hassona, Rifaat K. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan)], E-mail: rifaatk@yahoo.com; Sam, A.K. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan); Osman, O.I. [Chemistry Department, Faculty of Science, University of Khartoum (Sudan); Sirelkhatim, D.A. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan); LaRosa, J. [Formerly at IAEA Marine Environment Laboratory, 4 Quai Antoine 1er, MC 98000 (Monaco)

2008-04-15

308

Rethinking stock market integration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper aims to study the extent of integration among developed and emerg- ing stock markets in the onset of globalization through the formulation of a uni?ed conceptual framework that synthesizes the stock valuation model and the convergence hypothesis. Market integration manifests in the convergence of stock valuation ratios of markets in the long run, where valuation ratios are reflective of stock fundamentals driven by common global factors across markets. The spectrum of transition dy...

Tam, Pui Sun; Tam, Pui I.

2012-01-01

309

Assessing habitat specific fish assemblages in estuaries along the Portuguese coast  

Science.gov (United States)

Estuaries consist of a complex mosaic of many distinctive habitat types. Each one may perform several vital functions in the functioning of the whole system and although its value is often based on species density patterns, functional relationships between them also need to be examined. Spatial patterns of estuarine habitat use by fish assemblages were determined within and among nine estuarine systems along the Portuguese coast. Fish sampling surveys were conducted in May and July 2006, covering the full estuarine gradient. All the different habitat types were sampled in each estuarine system with a beam trawl. Estuarine habitats were mapped with GIS and habitat specific associated fish assemblages were described based on several community descriptors, namely richness ( S), evenness ( J'), and diversity ( H') and on an ecological and feeding guilds classification. A canonical correspondence analysis was performed to evaluate the relationship between estuarine habitats and fish assemblages in this set of estuaries. The intertidal and subtidal soft substratum habitats corresponded to the largest areas in all the estuaries and presented higher number of species. Nevertheless the highest mean density of fish was registered at the salt marsh habitat, which occupies smaller areas within each estuary. The fact that small vegetated habitats like salt marsh and seagrass supported high densities of fish may be an indication of the important role these habitats play in the whole system functioning. Differences in fish assemblage structure were found with latitude and between habitats amongst and within estuaries. Some of the fish species were found to be particularly associated with certain habitat types, which might indicate that each estuarine habitat may be related with specific fish assemblages regardless the estuary. The present work provides valuable information for management by identifying the most important habitats for species conservation and predicting the possible effects of habitat disturbance or destruction, namely by climate change and anthropogenic pressures.

França, Susana; Costa, Maria José; Cabral, Henrique N.

2009-06-01

310

Stocking impact and temporal stability of genetic composition in a brackish northern pike population ( Esox lucius L.), assessed using microsatellite DNA analysis of historical and contemporary samples  

DEFF Research Database (Denmark)

During the last decade, brackish northern pike populations in Denmark have been subject to stocking programmes, using nonindigenous pike from freshwater lakes, in order to compensate for drastic population declines. The present study was designed to investigate the genetic impact of stocking freshwater pike into a brackish pike population in Stege Nor, Denmark. We analysed polymorphism at eight microsatellite loci in samples representing the indigenous Stege Nor population prior to stocking (ie from 1956 to 1957), along with a sample of the contemporary Stege Nor population and samples from the three populations used for stocking. Despite large numbers of stocked fry, the results from both individual and population level admixture analyses demonstrated extremely poor performance and 250), but there were indications of bottlenecks in all samples and populations. We ascribe this finding to historical rather than recent bottlenecks, possibly dating back to founder events associated with postglacial recolonisation.

Larsen, Peter Foged; Hansen, Michael Møller

2005-01-01

311

Rotenone: An Essential but Demonized Tool for Assessing Marine Fish Diversity  

Science.gov (United States)

Coral reefs, one of the most biologically diverse and important ecosystems on Earth, are experiencing unprecedented and increasing ecological decline, yet the fish faunas of such reefs and other tropical shoreline habitats remain poorly known in many areas. Rotenone, a natural substance traditionally used by subsistence fishers, is a uniquely efficient tool for sampling reef and other shore fishes for marine research. Unfortunately, such sampling is perceived as being highly destructive, and increasing prohibitions against using rotenone in many countries will soon cripple essential research on reef-fish biodiversity worldwide. In this article we dispel common misconceptions about the environmental effects of small-scale rotenone sampling in marine research.

D. Ross Robertson (Smithsonian Tropical Research Institute;); William F. Smith-Vaniz (University of Florida;)

2008-02-01

312

Natural Propagation and Habitat Improvement, Washington, Volume IIA, Tumwater Falls and Dryden Dam Fish Passage, 1983 Final Report.  

Energy Technology Data Exchange (ETDEWEB)

This engineering feasibility and predesign report on the Tumwater Falls and Dryden Dam Fish Passage Project provides BPA with information for planning purposes and will serve as a discussion document for interested agencies. Tumwater Falls and Dryden Dams, both on the Wenatchee River, were built in the early 1900's as diversions for hydropower, and irrigation and hydropower, respectively. The present fishway facilities at both sites are inadequate to properly pass the anadromous fish runs in the Wenatchee River. These runs include spring and summer chinook salmon, sockeye salmon, coho salmon and steelhead trout. Predesign level drawings are provided in this report that represent fishway schemes capable of adequately passing present and projected fish runs. The effects of present passage facilities on anadromous fish stocks is addressed both quantitatively and qualitatively. The quantitative treatment assesses losses of adult migrants due to the structures and places an estimated value on those fish. The dollar figure is estimated to be between $391,000 and $701,000 per year for both structures. The qualitative approach to benefits deals with the concept of stock vigor, the need for passage improvements to help ensure the health of the anadromous fish stock. 29 references, 27 figures, 5 tables.

Unknown Author

1984-05-01

313

Assessment of fish health around the Terra Nova oil development site on the Grand Banks  

International Nuclear Information System (INIS)

American plaice are used as an indicator species for environmental effects monitoring (EEM) programs in the Grand Banks area of Newfoundland. This study reported on fish health studies conducted between 2000 to 2006 at the Terra Nova oil development site before and after the release of produced waters. A total of 500 fishes were studied for a 5-year period in order to evaluate health effect indicators including fish condition; visible skin and organ lesions; levels of mixed-function-oxygenase (MFO) enzymes; haematology; and various histopathological indices in the liver and gills. The study demonstrated slight elevations of MFO enzyme activity in fish from the development site in 2002, before the release of produced water. On the basis of the various studied indicators, results suggest that the project is not having a significant impact on the health of American plaice.

2009-09-27

314

Assessment of fish health around the Terra Nova oil development site on the Grand Banks  

Energy Technology Data Exchange (ETDEWEB)

American plaice are used as an indicator species for environmental effects monitoring (EEM) programs in the Grand Banks area of Newfoundland. This study reported on fish health studies conducted between 2000 to 2006 at the Terra Nova oil development site before and after the release of produced waters. A total of 500 fishes were studied for a 5-year period in order to evaluate health effect indicators including fish condition; visible skin and organ lesions; levels of mixed-function-oxygenase (MFO) enzymes; haematology; and various histopathological indices in the liver and gills. The study demonstrated slight elevations of MFO enzyme activity in fish from the development site in 2002, before the release of produced water. On the basis of the various studied indicators, results suggest that the project is not having a significant impact on the health of American plaice.

Mathieu, A.; Hanlon, J.; Melvin, W.; French, B. [Oceans Ltd., St. John' s, NL (Canada); Myers, M. [Northwest Fisheries Science Center, Seattle, WA (United States); Williams, U.; Janes, G. [Petro-Canada, East Coast Operations, St. John' s, NL (Canada); Wight, F. [Husky Oil Operations Ltd., St. John' s, NL (Canada)

2010-07-01

315

Metabolomics as a Powerful Tool for Molecular Quality Assessment of the Fish Sparus aurata  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The 1H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The f...

Gianfranco Picone; Søren Balling Engelsen; Francesco Savorani; Silvia Testi; Anna Badiani; Francesco Capozzi

2011-01-01

316

Fish Passage Assessment of an Advanced Hydropower Turbine and Conventional Turbine Using Blade-Strike Modeling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hydropower is the largest renewable energy source in the world. However, in the Columbia and Snake River basins, several species of Pacific salmon and steelhead have been listed for protection under the Endangered Species Act due to significant declines of fish population. Dam operators and design engineers are thus faced with the task of making hydroelectric facilities more fish friendly through changes in hydro-turbine design and operation. Public Utility District No. 2 of Grant County, Was...

Zhiqun Deng; Carlson, Thomas J.; Dauble, Dennis D.; Ploskey, Gene R.

2011-01-01

317

Spatial assessment of fishing effort around European marine reserves: Implications for successful fisheries management  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We examined the spatial dynamic of artisanal fishing fleets around five European marine protected areas (MPAs) to derive general implications for the evaluation of MPAs as fisheries management tools. The coastal MPAs studied were located off France, Malta and Spain and presented a variety of spatial designs and processes of establishment. We developed a standardized methodology to define factors influencing effort allocation and to produce fishing effort maps by merging GIS with geostatistica...

Stelzenmu?ller, Vanessa; Maynou, Francesc; Bernard, Guillaume; Cadiou, Gwenae?l; Camilleri, Matthew; Crechriou, Romain; Criquet, Ge?raldine; Dimech, Mark; Esparza, O?scar; Higgins, Ruth; Lenfant, Philippe; Pe?rez-ruzafa, A?ngel

2008-01-01

318

Evaluation of FISH image analysis system on assessing HER2 amplification in breast carcinoma cases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

ER2-positive breast cancer is characterized by aggressive growth and poor prognosis. Women with metastatic breast cancer with over-expression of HER2 protein or excessive presence of HER2 gene copies are potential candidates for Herceptin (Trastuzumab) targeted treatment that binds to HER2 receptors on tumor cells and inhibits tumor cell growth. Fluorescence in situ hybridization (FISH) is one of the most widely used methods to determine HER2 status. Typically, evaluation of FISH images invol...

Theodosiou, Z.; Kasampalidis, I.; Karagianopoulou, G.; Kostopoulos, I.; Bobos, M.; Bevilacqua, G.; Aretini, P.; Starita, A.; Lyroudia K.; Pitas. I.

2010-01-01

319

Experimental assessment of the effects of a Neotropical nocturnal piscivore on juvenile native and invasive fishes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus) fish species were offered as prey to P. corruscans in 300 L aqua...

Santos, Alejandra F. G. N.; Alcaraz Cazorla, Carles; Santos, Luciano N.; Hayashi, Carmino; Garci?a-berthou, Emili

2012-01-01

320

Quality loss assessment in fish-based ready-to-eat foods during refrigerated storage  

Directory of Open Access Journals (Sweden)

Full Text Available The present research addresses the quality loss in two different ready-to-eat (RTE seafoods. With this aim, chemical and microbiological parameters were measured in tuna lasagne (TL and hake roe foods which were refrigerated (4°C for up to 35 and 71 days, respectively. Both foods showed a significant lipid oxidation (peroxide and interaction compound formation development with storage time, which was especially marked in the case of the TL product, which also underwent an important lipid hydrolysis development. Both RTE products showed a low microbial development, no matter how much time had elapsed since the expiration dates; thus, low total viable count scores and volatile amine formation were attained while the presence of pathogen microorganisms was not detected. In view of the current increasing consumer demand for high quality refrigerated foods, the assessment of lipid damage related to nutritional and sensory values is recommended when fish-based RTE products are encountered.

Se estudió la pérdida de calidad de dos productos marinos elaborados (lasaña de atún, TL; huevas de merluza conservados en refrigeración (4 °C durante 35 y 71 días, respectivamente. Ambos alimentos mostraron un desarrollo importante de la oxidación lipídica (formación de peróxidos y compuestos de interacción durante el periodo de conservación, siendo mayor en el caso de TL; asimismo, el producto TL experimentó un importante desarrollo de hidrólisis lipídica. Sin embargo, ambos alimentos experimentaron un desarrollo bajo en microorganismos mesófilos y aminas volátiles; por otra parte, no maniferstaron presencia de microorganismos patógenos a lo largo del periodo de conservación, a pesar de sobrepasar el tiempo de caducidad. De acuerdo con la creciente demanda de nuevas preparaciones de alimentos refrigerados de calidad alta, se recomienda el estudio de las alteraciones lipídicas en elaboraciones basadas en alimentos de origen marino debido a su fuerte relación con la pérdida de calidades sensorial y nutricional.

Pourashouri, P.

2013-03-01

 
 
 
 
321

ASSESSMENT METHODS OF CORMORANT (Phalacrocorax carbo DIET  

Directory of Open Access Journals (Sweden)

Full Text Available Various cormorant diet assessment methods are used to assess their daily meal in order to evaluate, using these and other data, the damage to commercial fish farms as well as the damage on open waters caused by cormorants. All of the parameters used for evaluating the damage to fish stock (number of birds, density and fish structure, daily meal, fish price, degree of protection and preservation etc. are specific for an individual fishpond or other body of water and can only be used for that locality and not elsewhere. The results on the lowest and highest values of fish mass that cormorants eat daily vary extensively. By examining the available literature, the following values for individual adults have been determined: pellets — 347 g, pellets of captive cormorants — 371 g, stomach content — 359.5 g, regurgitations — 260 to 539 g, energy requirements — 751 g, stomach temperature — 336±98 g.

Krešimir Terzi?

2008-10-01

322

Reduced growth in hybrid tilapia ( Oreochromis mossambicus ×O. Niloticus) at intermediate stocking density  

Science.gov (United States)

Hybrid tilapia were reared at densities of 1, 5 or 10 fish per tank for four weeks. Mortality was 0 at 1 and 10 fish per tank, but was 25% at 5 fish per tank. Specific growth rate was highest at 1 fish per tank, and lowest at 5 fish per tank. The lower growth rate at the intermediate stocking density was associated with reduced feed efficiency, but there was no reduction in feed intake or digestibility. The results suggested increased metabolic cost caused by aggressive behaviour at intermediate stocking density, which can be suppressed by a further increase in density.

Wang, Yan; Cui, Yi-Bo; Yang, Yun-Xia; Cai, Fa-Sheng

2002-12-01

323

Estimation of the regional stock of residential buildings as a basis for a comparative risk assessment in Germany  

Directory of Open Access Journals (Sweden)

Full Text Available One important prerequisite for a comparable quantitative risk assessment for different types of hazards (e.g., earthquakes, windstorms and floods is the use of a common database about and financial appraisal of the assets at risk. For damage assessments it is necessary to represent the values at risk on a regional disaggregated scale and to intersect them with hazard scenarios. This paper presents a methodology and results of a financial appraisal of residential buildings for all communities in Germany. The calculated values are defined as replacement values for the reference year 2000. The resulting average replacement costs for residential buildings per inhabitant amount to EUR 46 600, with considerable differences between communities. The inventory can be used for the calculations of direct losses from various natural disasters within the project 'Risk Map Germany''.

L. Kleist

2006-01-01

324

Health risk assessment of hexachlorobenzene and hexachlorobutadiene residues in fish collected from a hazardous waste contaminated wetland in Louisiana, USA  

Energy Technology Data Exchange (ETDEWEB)

Improper disposal of hazardous materials has often led to significant adverse effects on environmental quality and human health. This investigation was undertaken to compare the concentration levels of hexachlorobenzene (HCB) and hexachlorobutadiene (HCBD) in various fish collected from a local hazardous waste contaminated wetland to those of a control site, and to assess the potential health risk that may be associated with consuming such fish. A total of 201 samples including 146 fish from the study site and 55 fish from a control site were examined. Statistical analyses revealed a highly significant difference i concentrations between the 2 sites. Mean levels of contaminants in edible tissues were 23.52 {+-} 53.54 ng/g (HCB) and 226.33 {+-} 778.40 ng/g (HCBD) in the study site, and 2.00 {+-} 5.62 ng/g (HCB) and 6.84 {+-} 10.41 ng/g (HCBD) in the control site. For the study site, a combined hazard index of 0.65 was computed for a 10-kg child eating 6.5 g of fish per day, while 70-kg adults with daily intakes of 6.5 g toxicant (general population), 30 g (sport fishermen) and 140 g (subsistence fishermen) yielded hazard indices of 0.11, 0.50 and 2.32, respectively, indicating that subsistence fishermen had a higher risk for systemic effects, with an exposure in excess of the EPA-Reference Dose. Cancer risks varied from 3.52 {times} 10{sup {minus}6} for HCB, and from 1.64 {times} 10{sup {minus}6} to 35.33 {times} 10{sup {minus}6} for HCBD, indicating an exposure in excess of the widely accepted risk level of 1 {times} 10{sup {minus}6}. For the control site, a significantly lower level of exposure was estimated for both HCB and HCBD.

Tchounwou, P.B. [Jackson State Univ., MS (United States). School of Science and Technology; Abdelghani, A.A.; Heyer, L.R. [Tulane Univ., New Orleans, LA (United States); Pramar, Y.V. [Xavier Univ. of Louisiana, New Orleans, LA (United States)

1998-12-31

325

Contributions to the assessment of Astacus leptodactylus Eschscholtz, 1823 stocks from the Razim-Sinoie lagoonary area (Danube Delta Biosphere Reserve, Romania  

Directory of Open Access Journals (Sweden)

Full Text Available In August 24th- August 30th, 2012 period there was performed a pilot study to assess the Slender clawded or Turkish crayfish (Astacus leptodactylus Eschscholtz, 1823 populations from Golovi?a Lake and the southern part of the Razim Lake (both of them located in the Danube Delta Biosphere Reserve - DDBR. There were used 10 sets of traps (each set with 10 traps and after 147 – 149 hours of functioning there were captured 45 specimens of A. leptodactylus, the total biomass of the crayfish being 1,768 g, which is a very low if compared with the official crayfish-quotas issued for various other regions of the DDBR. The scarcity in Astacus leptodactylus of the Razim- Sinoie lagoonary area is probably due to the habitat-requirement of this species (although other stressing factors – as plagues affecting the crayfish– could also be considered to explain the phenomenon. In order to harvest the minimum quantity (100 kg of crayfish issued as official quota in case of various other regions of the DDBR, the method involving 10 sets with 10 traps should be continuously used for about 370 days – the costs of activities for such long period (combined with the fact that in case of the exploited crayfish quantities there have to be paid various taxes for the environmental protection authorities makes economically unprofitable the crayfish stock-harvesting (based on the method used in the present study in the Razim and Golovi?a lakes .

TÖRÖK Zsolt Csaba

2013-12-01

326

A screening-level assessment of lead, cadmium, and zinc in fish and crayfish from Northeastern Oklahoma, USA  

Science.gov (United States)

The objective of this study was to evaluate potential human and ecological risks associated with metals in fish and crayfish from mining in the Tri-States Mining District (TSMD). Crayfish (Orconectes spp.) and fish of six frequently consumed species (common carp, Cyprinus carpio; channel catfish, Ictalurus punctatus; flathead catfish, Pylodictis olivaris; largemouth bass, Micropterus salmoides; spotted bass, M. punctulatus; and white crappie, Pomoxis annularis) were collected in 2001-2002 from the Oklahoma waters of the Spring River (SR) and Neosho River (NR), which drain the TSMD. Samples from a mining-contaminated site in eastern Missouri and from reference sites were also analyzed. Individual fish were prepared for human consumption in the manner used locally by Native Americans (headed, eviscerated, and scaled) and analyzed for lead, cadmium, and zinc. Whole crayfish were analyzed as composite samples of 5-60 animals. Metals concentrations were typically higher in samples from sites most heavily affected by mining and lowest in reference samples. Within the TSMD, most metals concentrations were higher at sites on the SR than on the NR and were typically highest in common carp and crayfish than in other taxa. Higher concentrations and greater risk were associated with fish and crayfish from heavily contaminated SR tributaries than the SR or NR mainstems. Based on the results of this and previous studies, the human consumption of carp and crayfish could be restricted based on current criteria for lead, cadmium, and zinc, and the consumption of channel catfish could be restricted due to lead. Metals concentrations were uniformly low in Micropterus spp. and crappie and would not warrant restriction, however. Some risk to carnivorous avian wildlife from lead and zinc in TSMD fish and invertebrates was also indicated, as was risk to the fish themselves. Overall, the wildlife assessment is consistent with previously reported biological effects attributed to metals from the TSMD. The results demonstrate the potential for adverse effects in fish, wildlife, and humans and indicate that further investigation of human health and ecological risks, to include additional exposure pathways and endpoints, is warranted. ?? Springer Science+Business Media B.V. 2006.

Schmitt, C. J.; Brumbaugh, W. G.; Linder, G. L.; Hinck, J. E.

2006-01-01

327

Assessment of risk of PCDD/Fs and dioxin-like PCBs in marine and freshwater fish in Pearl River Delta, China.  

Science.gov (United States)

Fish consumption is known to be beneficial to human health. However since the age of industrialization, the released/disposed chemical pollutants into water systems make fish a source of various environmental toxicants to humans. In oceanic cities with heavy industrial activities, fish products contribute the greatest proportion of exposure to pollutants. In this study, risks and potential effects of dioxins to health of coastal populations in the Pearl River Delta were assessed. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in common fish species purchased at local markets. Concentrations of total dioxins in fish ranged from 0.481 to 9.05 pg TEQ/g wet weight were similar to the lesser concentrations reported for fish from other countries. The greatest concentrations of dioxins were measured in mandarin fish, a carnivorous freshwater fish. Exposure of murine primary leydig and ovarian cells to 2,3,7,8-tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) reduced the synthesis of progesterone, testosterone and/or estrogen. The reductions were probably via inhibitory effects on the expression of the steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage enzyme (P450scc). Based on these reproductive parameters, the concentrations of dioxins and dioxin-like residues represent a moderate health risk due to consumption of fish. PMID:21392810

Wei, X; Leung, K S; Wong, M H; Giesy, J; Cai, Z W; Wong, Chris K C

2011-01-01

328

Assessment and exploitation of the pomfret fishery by the industrial fishing fleets in Bangladesh  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, pomfret fishery data were collected from the 93 commercial fishing trawlers from July 2008 to June 2009 in Bangladesh. Total fish production of these fishing trawlers was 30191.071 MetricTons (MT. Among them, the estimated catch of pomfret was 305.466 MT of which caught within total 18651961.05 hours and an average catch per hour of pomfret was 0.016 kilogram (kg. Three species of pomfret were recorded under the family stromateidae and carangidae. The average tow duration of per trawler per day was 16.25 hours. The percentage contribution by weight showed that, the highest catchof percentage was 1.88 and the lowest was 0.38; and the average catch percentage of pomfret was 1.01 of the total fish production in the trawl fishing. The highest landing of pomfret was recorded 65.460 MTin the month of November, 2008 and lowest was 1.146 MT in July, 2008 at the same study period.

Roy Bikram Jit

2013-08-01

329

Combating Illegal Fishing  

Directory of Open Access Journals (Sweden)

Full Text Available Illegal, unreported and unregulated (IUU fishing is a worldwide phenomenon. Its extent and its environmental,economic and social consequences are such that it has become a priority issue at international level. IUU fishingcontributes to the depletion of fish stocks and jeopardises protection and recovery measures put in place to ensure theviability of resources. It represents unfair competition for those who exploit fish resources legally. The Commissionhave been involved in the fight against IUU fishing for over a decade and in 2002 the Commission adopted an ActionPlan against IUU fishing inspired by the FAOs International Plan of Action to prevent, deter and eliminate IUUfishing of 2001. However, despite regional and international efforts to stop IUU fishing the phenomenon is still agrowing problem and as a result, the European Community intensified its action towards IUU fishing by launching aconsultation process in 2007. A Proposal to prevent, deter and eliminate IUU fishing was adopted in October 2007and a Regulation to prevent, deter and eliminate illegal, unreported and unregulated (IUU fishing was adopted on 29September 2008, after a unanimous political agreement.

Sorin Stanciu

2010-10-01

330

Fish Egg & Larval Surveys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The waters around Ireland contain some the most important spawning areas for north-east Atlantic fish stocks. Egg and Larval Surveys are a vital part of mapping these spawning areas and contribute to fisheries management decisions. Egg surveys can also give scientists an indication of the state of the spawning stock within a particular area by using what is called the Annual Egg Production (AEP) method. This method uses information on the number of eggs sampled in an area, and relates it to t...

Institute, Marine

2006-01-01

331

A review of image-based tools for automatic fish ageing from otolith features  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most of European fish stocks are assessed using age-based models, and otolith interpretation for age estimations costs several million euros annually. In this context, automated ageing systems would provide a mean to 1) standardize ageing, 2) control ageing consistency within and between ageing laboratories 3) build interpreted image data bases ensuring the information conservation and sharing and 4) improve growth studies while reducing the cost of the acquisition of age data. This paper pre...

2008-01-01

332

Use of fish farms to assess river contamination: combining biomarker responses, active biomonitoring, and chemical analysis.  

Science.gov (United States)

Here we addressed the possible effects of trace levels of contaminants on fish by means of a combination of biomarker responses, active biomonitoring (ABM), and chemical analysis. In environmental studies, cytochromes P4501A (Cyp1A) and Cyp3A and related enzyme activities (7-ethoxyresorufin-O-deethylase, EROD, and benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase, BFCOD, respectively) are commonly used as biomarkers for evidencing exposure to a variety of contaminants. In a rainbow trout (Oncorhynchus mykiss) fish farm that is routinely sampled to obtain references regarding normal levels of such enzyme activities in freshwater fish, we observed a strong and punctual increase in these activities at the end of 2011. In order to shed light on the causes of this induction, we transferred some fish to a fish farm with controlled conditions and examined them using an active biomonitoring (ABM) approach. EROD activity showed a decrease of 80% from the original values after 7 days in the control farm, while BFCOD activity was also reduced after 15 days. Although not significant, a decrease in cyp1A and cyp3A mRNA levels was also observed. To determine the presence of pollutants, water and sediment samples from the river feeding the fish farm were analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS). The screening study reflected a weak inflow of pollutants in the monitored area, which is located far from any industrial activity or densely populated cities. Trace levels of polyaromatic hydrocarbons (PAHs) and personal care products (the polycyclic musk fragrance HHCB, and triclosan) were detected in sediments, at concentrations ranging from 0.01 to 38 ng/g dry weight, and in water from 4 to 441 ng/L. The approach followed in this study proved useful as a biomonitoring technique for the early detection of trace contaminants. PMID:23928255

Quesada-García, Alba; Valdehita, Ana; Torrent, Fernando; Villarroel, Morris; Hernando, M Dolores; Navas, José M

2013-09-15

333

Information flow between composite stock index and individual stocks  

Science.gov (United States)

We investigate the strength and the direction of information transfer in the US stock market between the composite stock price index of stock market and prices of individual stocks using the transfer entropy. Through the directionality of the information transfer, we find that individual stocks are influenced by the index of the market.

Kwon, Okyu; Yang, Jae-Suk

2008-05-01

334

Risk assessment for fish passage through small, low-head turbines  

International Nuclear Information System (INIS)

This report summarises the findings of a study to improve the accuracy of prediction methods for fish fatalities for small-head Francis and Kaplan propeller turbine designs and gives details of computational fluid dynamic modelling to estimate pressure fluxes and shear stresses. Biological data is reviewed, and the STRIKER Excel spreadsheet model is used to predict death caused by pressure flux, shear turbulence, and blade strike. Field validation is discussed, and drawings of the Francis 1 and Kaplan 1 turbines, results of the fish passage trials, and STRIKER instructions and sample runs are presented in the appendices

2000-01-01

335

Genetic enetic characterization of curimba (“Prochilodus lineatus”) stocks used in stock enhancement programs Caracterização genética de estoques de curimba ("Prochilodus lineatus") utilizados em programas de repovoamento  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim with this study was to determine the genetic diversity of P. lineatus stocks, destined to stocking programs, with the RAPD molecular marker (Random Amplified Polymorphic DNA). Fifty two broodstocks of two fish farmings located at Salto Grande - SP (A) and Palotina - PR (B) counties and 32 juvenile progenies of Palotina stock (C) were analyzed. The six primers produced 63 fragments (96.83% polymorphism). The genetic variability values determined by the polymorphic fragments percentage ...

Taís da Silva Lopes; Ricardo Pereira Ribeiro; Nelson Mauricio Lopera Barrero; Rodolfo Nardez Sirol; Jayme Aparecido Povh; Patrícia Cristina Gomes; Lauro Vargas

2008-01-01

336

Assessment of general condition of fish inhabiting a moderately contaminated aquatic environment.  

Science.gov (United States)

The assessment of general condition of fish in the moderately contaminated aquatic environment was performed on the European chub (Squalius cephalus) caught in September 2009 in the Sutla River in Croatia. Although increases of the contaminants in this river (trace and macro elements, bacteria), as well as physico-chemical changes (decreased oxygen saturation, increased conductivity), were still within the environmentally acceptable limits, their concurrent presence in the river water possibly could have induced stress in aquatic organisms. Several biometric parameters, metallothionein (MT), and total cytosolic protein concentrations in chub liver and gills were determined as indicators of chub condition. Microbiological and parasitological analyses were performed with the aim to evaluate chub predisposition for bacterial bioconcentration and parasitic infections. At upstream river sections with decreased oxygen saturation (~50%), decreased Fulton condition indices were observed (FCI: 0.94 g?cm(-3)), whereas gonadosomatic (GSI: 2.4%), hepatosomatic (HSI: 1.31%), and gill indices (1.3%) were increased compared to oxygen rich downstream river sections (dissolved oxygen ~90%; FCI: 1.02 g?cm(-3); GSI: 0.6%; HIS: ~1.08%; gill index: 1.0%). Slight increase of MT concentrations in both organs at upstream (gills: 1.67 mg?g(-1); liver: 1.63 mg?g(-1)) compared to downstream sites (gills: 1.56 mg?g(-1); liver: 1.23 mg?g(-1)), could not be explained by induction caused by increased metal levels in the river water, but presumably by physiological changes caused by general stress due to low oxygen saturation. In addition, at the sampling site characterized by inorganic and fecal contamination, increased incidence of bacterial bioconcentration in internal organs (liver, spleen, kidney) was observed, as well as decrease of intestinal parasitic infections, which is a common finding for metal-contaminated waters. Based on our results, it could be concluded that even moderate contamination of river water by multiple contaminants could result in unfavourable living conditions and cause detectable stress for aquatic organisms. PMID:23322414

Dragun, Zrinka; Filipovi? Mariji?, Vlatka; Kapetanovi?, Damir; Vali?, Damir; Vardi? Smrzli?, Irena; Krasni?i, Nesrete; Strižak, Željka; Kurtovi?, Božidar; Teskeredži?, Emin; Raspor, Biserka

2013-07-01

337

Baseline studies of fish blood  

Energy Technology Data Exchange (ETDEWEB)

Recent literature of baseline studies on fish blood chemistry, physiology, blood cell abundance, and morphology are reviewed. Studies on possible sources of interspecific and intraspecific variation in baseline values of fish blood are discussed. A selected and annotated bibliography of baseline and temperature studies on fish blood is included in this report. Hematological methodologies for fish were developed and implemented in a study to determine the effects of stocking density on blood chemistry and cell morphology. The effects of culture composition on the hematology of adult bluegill were examined to determine the validity of using monocultures to characterize potential environmental perturbations. Results indicated that monoculture data were valid to use as controls.

Murray, S.A.

1983-03-01

338

Robust stock option plans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main purpose of this paper is to address the issue of robustness of stock option plans, which is essential for reliable accounting valuations. The introduction of the accounting standards SFAS 123R and IFRS 2 for executive stock options has led to an important change. As companies are now forced to value their stock options at grant date for accounting purposes, the robustness of prices against the choice of certain valuation models and input parameters has become a very important issue. ...

Korn, Olaf; Paschke, Clemens; Uhrig-homburg, Marliese

2011-01-01

339

Evaluating Market Risk Assessment through VAR Approach before and after Financial Crisis in Tehran Stock Exchange Market (TSEM  

Directory of Open Access Journals (Sweden)

Full Text Available the goal of the present research is to evaluate the performance of 4 models of assessing value at risk, namely Simple VaR, Risk Metric VaR, GARCH (1,1, and GJR-GARCH in the way to introduce the most reliable one to be used under special circumstances of financial crisis. The method used in order to do so has been the volatilities of the all share index and those of the industrial index in TSEM between 2003 and 2013 were employed. In order to elicit points of crisis in the aforementioned span of time, partial regression was employed. The findings indicated 3 points of crisis; the two more recent ones, the ones in 2009 and 2012, were chosen. For each period of crisis, the data on the period between this target crisis and the one beforehand was used so to estimate models. In addition, the data between the target crisis and the one afterwards was employed so to validate the models. Validation tests for the models were carried out at three confidence levels of 95%, 97.5%, and 99%, using Cupic, Christopherson, and Lopez tests. The findings indicated that the models employed for the study have a desirable level of ability at predicting market risk in the periods of crisis. In addition, the findings of testing minor hypotheses of the study showed that parallel to increasing level of confidence for the models, GARCH (1,1 has a better performance in comparison to VaR model. The present paper aimed at measuring market risk which has been one of the basic goals of TSEM. This supports the cause of carrying out this study. In addition to this, investors in the market, too, would support carrying this study as necessary. It is claimed in this article that simple VaR, Simple GARCH, and GJR-GARCH are useful to predict risk of the market under financial crisis circumstances.

Mirfeiz Fallah Shams

2014-05-01

340

Polycyclic aromatic hydrocarbons in fish. Exposure assessment for Kuwaiti consumers after the gulf oil spill of 1991  

International Nuclear Information System (INIS)

This investigation involves a preliminary assessment of public health hazards associated with exposure to PAHs in locally consumed fish from oil-impacted areas after the Gulf oil spill in 1991. Based on levels of 10 PAHs determined in edible parts of fish collected during the NOAA-Mt. Mitchell scientific cruise (April-May 1992), two exposure scenarios were hypothesized. The first scenario considers that the extent of exposure to PAHs is influenced by the frequency of occurrence and the mean concentration of individual PAH compounds. In the second scenario, the maximum detected PAH concentrations are considered as potential extremes in exposure based on the likely preference of consumption of highly contaminated fish. The mean concentration of the frequently occurring pyrene (75%) poses 3.8, 2.37, and 5.85 times the carcinogenic equivalency, carcinogenic potency, and mutagenic potency, respectively, posed by the mean B(a)P concentration. The maximum concentration of pyrene poses 5.81, 3.62, 8.94 times the carcinogenic equivalency, carcinogenic potency, and mutagenic potency, respectively, posed by the maximum B(a)P concentration. The mean concentration of anthracene (frequency of occurrence = 10%) poses 8.05 and 1.51 times the carcinogenic potency and mutagenic potency, respectively, posed by the mean B(a)P concentration. 16 refs., 1 fig., 6 tabs

1994-01-01

 
 
 
 
341

Polycyclic aromatic hydrocarbons in fish. Exposure assessment for Kuwaiti consumers after the gulf oil spill of 1991  

Energy Technology Data Exchange (ETDEWEB)

This investigation involves a preliminary assessment of public health hazards associated with exposure to PAHs in locally consumed fish from oil-impacted areas after the Gulf oil spill in 1991. Based on levels of 10 PAHs determined in edible parts of fish collected during the NOAA-Mt. Mitchell scientific cruise (April-May 1992), two exposure scenarios were hypothesized. The first scenario considers that the extent of exposure to PAHs is influenced by the frequency of occurrence and the mean concentration of individual PAH compounds. In the second scenario, the maximum detected PAH concentrations are considered as potential extremes in exposure based on the likely preference of consumption of highly contaminated fish. The mean concentration of the frequently occurring pyrene (75%) poses 3.8, 2.37, and 5.85 times the carcinogenic equivalency, carcinogenic potency, and mutagenic potency, respectively, posed by the mean B(a)P concentration. The maximum concentration of pyrene poses 5.81, 3.62, 8.94 times the carcinogenic equivalency, carcinogenic potency, and mutagenic potency, respectively, posed by the maximum B(a)P concentration. The mean concentration of anthracene (frequency of occurrence = 10%) poses 8.05 and 1.51 times the carcinogenic potency and mutagenic potency, respectively, posed by the mean B(a)P concentration. 16 refs., 1 fig., 6 tabs.

Al-Yakoob, S.N.; Saeed, T.; Al-Hashash, H. (Kuwait Inst. for Scientific Research, Safat (Kuwait))

1994-01-01

342

Time changes in fishing power in the Danish cod fisheries of the Baltic Sea  

DEFF Research Database (Denmark)

Using nominal fishing effort to control fishing mortality and using cpue data from commercial fisheries as abundance indices require ability to correct fishing power for temporal development. It is often assumed in ICES stock assessments that fishing power Is constant over time. However, experience has suggested that this assumption may be false. This study investigates the time dynamics of an Index of Fishing Power (IFP). This index is based on the fleets cpue. relative to the cpue of a subset of vessels from the same fleet. The primary characteristic of the reference vessels is that their fishing power has not varied much over time. IFP is calculated for some of the Danish cod fisheries in the Baltic Sea. IFP appeared to be independent of the vessel composition of the reference sub- fleet and for the fleets fishing in the Eastern Baltic Sea. but less so for the Western Baltic Sea fleets. Variations in IFP are analysed by a GLM (General Linear Model). Results suggest that fishing power has developed in the Eastern Baltic Sea cod fishery at an annual rate of 2% and 6% for trawlers and gillnetters respectively. Mechanisms of fishing power creeping may include increased technical efficiency and also changes in vessel composition of the fleets over the period of analysis. (C) 2001 International Council for the Exploration of the Sea.

Marchal, P.; Nielsen, J. Rasmus

2001-01-01

343

Assessing the feasibility of native fish reintroductions: a framework and example applied to bull trout in the Clackamas River, Oregon  

Science.gov (United States)

In a species conservation context, translocations can be an important tool, but they frequently fail to successfully establish new populations. We consider the case of reintroductions for bull trout (Salvelinus confluentus), a federally-listed threatened species with a widespread but declining distribution in western North America. Our specific objectives in this work were to: 1) develop a general framework for assessing the feasibility of reintroduction for bull trout, 2) provide a detailed example of implementing this framework to assess the feasibility of reintroducing bull trout in the Clackamas River, Oregon, and 3) discuss the implications of this effort in the more general context of fish reintroductions as a conservation tool. Review of several case histories and our assessment of the Clackamas River suggest that an attempt to reintroduce bull trout could be successful, assuming adequate resources are committed to the subsequent stages of implementation, monitoring, and evaluation.

Dunham, Jason; Gallo, Kirsten

2008-01-01

344

Absence of subtelomeric rearrangements in selected patients with mental retardation as assessed by multiprobe T FISH  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Mental retardation (MR is a heterogeneous condition that affects 2-3% of the general population and is a public health problem in developing countries. Chromosomal abnormalities are an important cause of MR and subtelomeric rearrangements (STR have been reported in 4-35% of individuals with idiopathic MR or an unexplained developmental delay, depending on the screening tests and patient selection criteria used. Clinical checklists such as that suggested by de Vries et al. have been used to improve the predictive value of subtelomeric screening. Findings Fifteen patients (1–20 years old; five females and ten males with moderate to severe MR from a genetics outpatient clinic of the Gaffrée and Guinle Teaching Hospital (HUGG of the Federal University of Rio de Janeiro State (UNIRIO were screened with Multiprobe T FISH after normal high resolution karyotyping. No subtelomeric rearrangements were detected even though the clinical score of the patients ranged from four to seven. Conclusion In developing countries, FISH-based techniques such as Multiprobe T FISH are still expensive. Although Multiprobe T FISH is a good tool for detecting STR, in this study it did not detect STR in patients with unexplained MR/developmental delay even though these patients had a marked chromosomal imbalance. Our findings also show that clinical scores are not reliable predictors of STR.

dos Santos Suely Rodrigues

2012-12-01

345

The Assessment of Natural Radionuclides in Sea Fish from Gresik Coastal Marines  

International Nuclear Information System (INIS)

Gresik coastal marines is the place used for the disposal of wastes from many industries such as phosphate fertilizer factory that is suspected to discharge natural radionuclide. This factory utilizes phosphate rock as raw material for producing phosphate acid and fertilizer, so that the product, by product and the waste could contained natural radionuclide. The discharge of waste to the marine will be potential pollutant to coastal environment and increased the contents of natural radionuclide in marine biota including fish. Therefore research on the quality and concentration of natural radionuclide in sea-fish from that area has been done. The result showed that there were 238U, 232Th and 226Ra also 40K in all types of sea-fish analyzed. In general, specific activities of 238U in the sea-fish sample was higher than those of 232Th and 226Ra, and the concentration were ranged 1.60 - 2.05 Bq/kg; 0.23 - 5.48 Bq/kg and 0.48 - 3.34 Bq/kg respectively. There were the tendency that bottom feeding species, such as Penaeldae, Portunus pelagicus and Plotosus anguilaris contained higher natural radionuclide compared to the other species. (author)

2003-03-01

346

Assessment of pond water quality of Thakurgaon sadar upazila for fish production  

Directory of Open Access Journals (Sweden)

Full Text Available During dry season, physico-chemical properties of waters from 30 ponds of Thakugaon Sadar Upazila, Thakurgaon, Bangladesh were analyzed for its quality and suitability for aquaculture. The variation in the physico-chemical parameters of the aquaculture ponds above or below standard values has potential effects on the health and productivity of aquaculture. Overall, we found that the pond water were acidic to neutral in nature (pH varied from 6.0 to 7.2 and could be suitable for aquaculture. The dissolved oxygen (DO concentration was suitable for fish production but more DO level should be present for all aquatic life especially for fish production. Chemical oxygen demands (COD of all pond waters were within the permissible limits for fish production. The temperature values were remained within the standard values in all the aquaculture ponds. Pond water samples contained Ca2+, Mg2+ and Na+ as the dominant cations and HCO3- and Cl- were the dominant anions. All samples were within ‘soft’ class regarding hardness. Based on Zn2+, Mn2+, Fe3+, SO42-, NO3- and Cl- all pond water samples were within the ‘safe’ limit for fish production during dry period.

M.J. Islam

2013-06-01

347

Assessment of a commercial kit collection for diagnosis of the fish viruses: IHNV, IPNV, SVCV and VHSV.  

DEFF Research Database (Denmark)

A commercial kit collection for the detection of the fish pathogenic viruses, VHSV, IHNV, IPNV, and SVCV, was assessed for its ability to detect isolates in selected panels of the respective viruses. The kit collection, which was based on fluorescence staining of infected cell cultures in tissue culture plates, fulfilled the promised requirements for the IHN kit only. The IPN, the SVC and especially the VHS kit were lacking in either specificity or sensitivity. The findings stress the need for commercial companies to carry out proper validation before market release.

Ariel, Ellen; Olesen, Niels Jørgen

2001-01-01

348

Quantity, quality, and support for research in the U.S. Fish and Wildlife Service: an organizational assessment  

Science.gov (United States)

To develop a clearer picture of the nature, extent and quality of management support available for conducting research within the FWS, we completed investigations to identify organizational units within the U.S. Fish and Wildlife Service (FWS) that conduct research as a significant portion of their mission; identify positions in the FWS that include, in whole or in part, a component of scientific research; and assess the attitudes of employees and managers about the obstacles and opportunities for scientific research existing within the FWS.

Ratz, Joan M.; Ponds, Phaedra D.; Neilson, Jennifer R.; Liverca, Joyce; Lamb, Berton Lee

2005-01-01

349

Study design considerations for assessing the health of fish populations impacted by agriculture in developing countries: a Sri Lankan case study.  

Science.gov (United States)

Studies on the use of indigenous or endemic fish species for the assessment of agricultural impacts on fish populations are lacking in tropical South and Southeast Asia. This paper describes the steps involved in developing an agricultural impacts assessment program focused on river health, using recent studies on wild fish in Sri Lanka. The assessment methodology includes the selection of fish species for monitoring, and development of a strategy for sample timing, sample size requirements, and selection of appropriate reference site(s). Preliminary fish sampling data from several tributaries of the Uma-oya and the Amban-ganga (Knuckles streams) from the Mahaweli River basin were evaluated and temporal patterns of gonadal recruitment were investigated for three common species: Garra ceylonensis, Devario malabaricus, and Rasbora daniconius. The data on reproductive development were statistically incorporated to evaluate appropriate sample timing and sample size requirements. For this study, we proposed a cluster gradient design with a range of assessment endpoints and suitable statistical methods; an alternate assessment in different agricultural catchments would facilitate verification. The review and preliminary data support provide a template for study design considerations for agricultural impact assessments in South and SE Asian countries. PMID:21769414

Sumith, Jayakody A; Munkittrick, Kelly R

2011-08-01

350

Assessment of chromosomal abnormalities in sperm of infertile men using sperm karyotyping and multicolour fluorescence in situ hybridization (FISH)  

Energy Technology Data Exchange (ETDEWEB)

Individuals with male factor infertility resulting from idiopathic oligo-, astheno- or teratozoospermia are frequently offered IVF in an attempt to increase their chances of having a child. A concern remains whether these infertile males have an elevated risk of transmitting chromosomal abnormalities to their offspring. Sperm chromosomal complements from these men were assayed using the human sperm/hamster oocyte fusion system and fluorescence in situ hybridization (FISH) on sperm nuclei. For each of 5 infertile patients, 100 sperm karyotypes were analyzed and multicolour FISH analysis was performed on a minimum of 10,000 sperm nuclei for each chromosome-specific DNA probe for chromosomes 1 (pUC1.77), 12 (D12Z3), X (XC) and Y (DYZ3). As a group, the infertile patients showed increased frequencies of both numerical ({chi}{sup 2}=17.26, {proportional_to} <0.001) and total abnormalities ({chi}{sup 2}=7.78, {proportional_to} <0.01) relative to control donors when assessed by sperm karyotypes. Analysis of sperm nuclei by FISH indicated a significant increase in the frequency of disomy for chromosome 1 in three of the five patients as compared to control donors ({chi}{sup 2}>8.35, {proportional_to} <0.005). In addition, the frequency of XY disomy was significantly higher in four of the five patients studied by FISH ({chi}{sup 2}>10.58, {proportional_to}<0.005), suggesting that mis-segregation caused by the failure of the XY bivalent to pair may play a role in idiopathic male infertility.

Moosani, N.; Martin, R.H. [Alberta Children`s Hospital and Univ. of Calgary (Canada)

1994-09-01

351

Using ordination and clustering techniques to assess multimetric fish health response following a coal ash spill.  

Science.gov (United States)

The effect of coal ash exposure on fish health in freshwater communities is largely unknown. Given the large number of possible pathways of effects (e.g., toxicological effect of exposure to multiple metals, physical effects from ash exposure, and food web effects), measurement of only a few health metrics is not likely to give a complete picture. The authors measured a suite of 20 health metrics from 1100+ fish collected from 5 sites (3 affected and 2 reference) near a coal ash spill in east Tennessee over a 4.5-yr period. The metrics represented a wide range of physiological and energetic responses and were evaluated simultaneously using 2 multivariate techniques. Results from both hierarchical clustering and canonical discriminant analyses suggested that for most species?×?season combinations, the suite of fish health indicators varied more among years than between spill and reference sites within a year. In a few cases, spill sites from early years in the investigation stood alone or clustered together separate from reference sites and later year spill sites. Outlier groups of fish with relatively unique health profiles were most often from spill sites, suggesting that some response to the ash exposure may have occurred. Results from the 2 multivariate methods suggest that any change in the health status of fish at the spill sites was small and appears to have diminished since the first 2 to 3 yr after the spill. Environ Toxicol Chem 2014;33:1903-1913. Published 2014 Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America. PMID:24764206

Bevelhimer, Mark S; Adams, S Marshall; Fortner, Allison M; Greeley, Mark S; Brandt, Craig C

2014-08-01

352

Asymmetric Effects in Emerging Stock Markets - The Case of Iran Stock Market  

Directory of Open Access Journals (Sweden)

Full Text Available In view of the mixed empirical results in the literature, this paper assesses the extent of asymmetric volatility effects in the Iranian stock market as an emerging stock market, using a variety of nonlinear autoregressive conditional heteroskedasticity specifications. Tests based on standardized residuals from a fitted GARCH model suggest a lack of asymmetric effects in the dynamic volatility of the Iranian stock market. Empirical analyses with asymmetric GARCH models also reject the hypothesis of asymmetric volatility, in contrast to most developed and emerging markets. Hence, good and bad news of the same magnitude have similar impacts on the volatility level in the Iranian stock market. The leverage effect modified by inflation advantage and price limit may be the main reasons for lack of asymmetric effect in emerging stock markets.

Seyyed Ali Paytakhti Oskooe

2011-10-01

353

Quantitative and qualitative aspects of fish crop in relation to environmental quality  

Energy Technology Data Exchange (ETDEWEB)

The effects of environmental quality on the quantitative and qualitative aspects of fish crop are reviewed with reference to fisheries in rivers, lakes, reservoirs, and coastal waters ranging from the temperate zone to subtropical areas in mainland China. The mechanism of these effects is discussed, and the insidiousness of long-term exposure to low-concentration pollutants to fish stock is stressed. Regarding the assessment of the effect of pollution on fish, most of our information has been derived from laboratory studies, in which the antagonistic or synergistic action between multiple pollutants was scarcely taken into consideration. One has to be cautious when the results of laboratory experiments are extrapolated to the realistic natural environment. It is advocated that surveys and tests concerning the relation between environmental quality and fish life be made on natural waters in addition to laboratory studies, and the effects be elucidated at the individual level, population level, and the ecosystem level.

Liu, J.K.; He, X.Q.

1987-02-01

354

Solow Residuals Without Capital Stocks  

DEFF Research Database (Denmark)

We use synthetic data generated by a prototypical stochastic growth model to assess the accuracy of the Solow residual (Solow, 1957) as a measure of total factor productivity (TFP) growth when the capital stock in use is measured with error. We propose two alternative measurements based on current investment expenditures: one eliminates the capital stock by direct substitution, while the other employs generalized differences of detrended data and the Malmquist index. In short samples, these measures can exhibit consistently lower root mean squared errors than the Solowâ??Törnqvist counterpart. Capital measurement problems are particularly severe for economies still far from their steady state. This drawback of the Solow residual is thus most acute in applications in which its accuracy is most highly valued. As an application, we compute and compare TFP growth measures for developing countries in the Hestonâ??Summers dataset.

Burda, Michael C.; Severgnini, Battista

2014-01-01

355

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 in the number of species compared to other Brazilian reef sites. Trophic structure and biogeographical affinities are discussed. The absence of some reef fish species, mainly top predators, suggests severe environmental impact in this area and exhorts the Brazilian authorities to create a marine protected area. Results obtained in this study will serve to future environmental studies in Cagarras.A extensa costa brasileira abriga uma grande diversidade de peixes recifais. Este trabalho é um estudo pioneiro no que diz respeito à composição de espécies de peixes recifais do Arquipélago das Cagarras. Este sistema recifal é formado por um grupo de ilhas costeiras, distantes 5 km ao sul da Praia de Ipanema no estado do Rio de Janeiro, Brasil. Uma comunidade relativamente diversa e impactada, com 99 espécies pertencentes a 39 famílias de peixes recifais, foi encontrada. A utilização de duas técnicas de censo visual mostrou uma grande diferença nos dados obtidos, quando comparados a outras regiões recifais brasileiras. São discutidos dados da estrutura trófica e a distribuição biogeográfica da ictiofauna da região. A ausência de algumas espécies, principalmente grandes predadores, sugere que a região está sofrendo grande impacto ambiental, e torna urgente a criação de uma área de proteção marinha pelas autoridades Brasileiras. Os resultados obtidos poderão servir como base para futuros estudos ambientais nas Cagarras.

Carlos A. Rangel

2007-03-01

356

Assessment of Water Quality in Asa River (Nigeria) and Its Indigenous Clarias gariepinus Fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water is a valued natural resource for the existence of all living organisms. Management of the quality of this precious resource is, therefore, of special importance. In this study river water samples were collected and analysed for physicochemical and bacteriological evaluation of pollution in the Unity Road stream segment of Asa River in Ilorin, Nigeria. Juvenile samples of Clarias gariepinus fish were also collected from the experimental Asa River and from the control Asa Dam water and we...

Kolawole, Olatunji M.; Ajayi, Kolawole T.; Olayemi, Albert B.; Okoh, Anthony I.

2011-01-01

357

The Occurrence and Risk Assessment of the Pesticide Toxaphene in Fish from Irish Waters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The European Union project “Investigation into the monitoring, analysis and toxicity of toxaphene” (MATT), involving participants from The Netherlands, Ireland, Norway and Germany, began in 1997. Analytical methodology, concentration information and statistical interpretation of results for three indicator congeners, CHB’s 26, 50 and 62, are presented. Data from 55 samples, covering 18 different fish species, from Irish waters are documented. Concentrations were lowest in shellfish and ...

Mchugh, B.; Glynn, D.; Nixon, E.; Mcgovern, E.

2003-01-01

358

Mercury and selenium accumulation assessment in fish most consumed by Cubatao Community, Sao Paulo, Brazil  

Energy Technology Data Exchange (ETDEWEB)

High correlation between mercury (Hg) and selenium (Se) concentrations in fish organs is well known. In the present study, 58 fish samples of five fish species most commonly consumed by the Cubatao city population, Sao Paulo State, Brazil were analyzed. The Cubatao Estuary, located in southeastern Sao Paulo State, is an economically important area suffering severe environmental water quality problems due to industrial wastes, domestic sewage and solid residues. The waters of the bay suffer the impact of the immense industrial complex of Cubatao. In this study, Hg concentration in muscle, liver and kidney tissues and Se concentration in liver tissue from three predatory fish species: Macrodon ancylodon (Pescada), Menticirrhus americanus (Perna de Moca) and Micropogonias furnieri (Corvina) and two planctivorous species: Mugil liza (Tainha) and Sardella braziliensis (Sardinha) were determined. Mercury determination was performed using Cold Vapour Atomic Absorption Spectrometry (CV AAS) and selenium by Instrumental Neutron Activation Analysis (INAA). The muscle-Hg concentration variation (wet weight) was: (8 to 40 mug kg{sup -1}) - Sardinha; (12 to 62 mug kg{sup -1}) - Pescada; (3 to 23 mug kg{sup -1}) - Tainha; (43 to 184 mug kg{sup -1}) - Perna de Moca and (41 to 348 mug kg{sup -1}) - Corvina. The general concentration ranges of the analyzed elements in all species studied were (dry weight): muscle-Hg (13 to 1512 mug kg{sup -1}); liver-Hg (21 to 1804 mug kg{sup -1}); kidney-Hg 47 to 9912 mug kg{sup -1}) and liver-Se (2.10 to 43.00 mg kg{sup -1}). Se concentrations were higher than those of Hg in the liver. (author)

Farias, Luciana A.; Favaro, Deborah I.T.; Curcho, Michel R.S.M.; Fonseca, Barbara C.; Nascimento, Soraia M., E-mail: lufarias2@yahoo.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil). Lab. de Analise por Ativacao de Neutrons; Kunioshi, Leonardo; Braga, Elisabete S., E-mail: edsbraga@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos (LABNUT)

2009-07-01

359

Assessment of pollution in the west black sea coast of turkey using biomarker responses in fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Aim of this study was to determine the extent of pollution in the West Black Sea Coast of Turkey by measuring CYP1A associated EROD activity, phase II enzyme, glutathione S-transferase and antioxidant enzymes, catalase and glutathione reductase activities and immunochemical detection of CYP1A protein level in the liver of mullet. The fish samples were caught from six locations having a varying degree of pollution in the West Black Sea Region of Turkey in August 2005, 2006 ...

2009-01-01

360

Mercury and selenium accumulation assessment in fish most consumed by Cubatao Community, Sao Paulo, Brazil  

International Nuclear Information System (INIS)

High correlation between mercury (Hg) and selenium (Se) concentrations in fish organs is well known. In the present study, 58 fish samples of five fish species most commonly consumed by the Cubatao city population, Sao Paulo State, Brazil were analyzed. The Cubatao Estuary, located in southeastern Sao Paulo State, is an economically important area suffering severe environmental water quality problems due to industrial wastes, domestic sewage and solid residues. The waters of the bay suffer the impact of the immense industrial complex of Cubatao. In this study, Hg concentration in muscle, liver and kidney tissues and Se concentration in liver tissue from three predatory fish species: Macrodon ancylodon (Pescada), Menticirrhus americanus (Perna de Moca) and Micropogonias furnieri (Corvina) and two planctivorous species: Mugil liza (Tainha) and Sardella braziliensis (Sardinha) were determined. Mercury determination was performed using Cold Vapour Atomic Absorption Spectrometry (CV AAS) and selenium by Instrumental Neutron Activation Analysis (INAA). The muscle-Hg concentration variation (wet weight) was: (8 to 40 ?g kg-1) - Sardinha; (12 to 62 ?g kg-1) - Pescada; (3 to 23 ?g kg-1) - Tainha; (43 to 184 ?g kg-1) - Perna de Moca and (41 to 348 ?g kg-1) - Corvina. The general concentration ranges of the analyzed elements in all species studied were (dry weight): muscle-Hg (13 to 1512 ?g kg-1); liver-Hg (21 to 1804 ?g kg-1); kidney-Hg 47 to 9912 ?g kg-1) and liver-Se (2.10 to 43.00 mg kg-1). Se concentrations were higher than those of Hg in the liver. (author)

2009-10-02

 
 
 
 
361

Population structure and stock assessment of Hoplias malabaricus (Characiformes: Erythrinidae) caught by artisanal fishermen in river-reservoir transition area in Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: English Abstract in spanish Hoplias malabaricus representa una alternativa económica viable para los pescadores artesanales que viven a la orilla de ríos que actualmente cuentan con represas en Brasil. El objeto del presente estudio fue evaluar la dinámica de la reproducción, alimentación, crecimiento y nivel de explotación de [...] la especie nativa Hoplias malabaricus, capturada por pescadores artesanales en la zona de transición entre el río Paranapanema y el Embalse de Jurumirim. En 2005, los especimenes de H. malabaricus se obtuvieron utilizando redes agalleras de forma mensual y se registraron las siguientes características y datos biológicos de cada uno: longitud estándar, peso corporal, sexo, estadio reproductivo, peso de las gónadas y contenido estomacal. Estos datos fueron utilizados para estimar la proporción sexual, el período reproductivo y los hábitos alimenticios. Para evaluar los parámetros de crecimiento y el grado de explotación, los datos de frecuencia de la longitud estándar fueron analizados utilizando el software FISAT a través de la rutina ELEFAN I. Según los resultados obtenidos, la proporción sexual fue de 0.8:1 (macho:hembra); la reproducción fue observada durante todo el año, pero sobre todo en la primavera y el verano. El hábito alimentario fue piscívoro. Los parámetros de crecimiento y mortalidad fueron estimados en: L?=35.18cm, k=0.32/año; longevidad= 9.3, Z=1.25/año, M=0.63/año y F=0.62/año. La relación longitud-peso fue: Wt=-3.1663+2.7456lnLp. El análisis de rendimiento por recluta estimó los siguientes valores: E=0.496, Emax=0.916, E0.1=0.701 y E0.5=0.378. Puede concluirse que la población de H. malabaricus en la región estudiada todavía no está siendo altamente explotada. Abstract in english Hoplias malabaricus is a viable economic alternative for artisanal fishermen who used to live on the banks of rivers that now are dammed in Brazil. In order to preserve the species’ natural stock, the main objectives of this study were to obtain bio-ecological information on this species reproductio [...] n, feeding dynamics and the description of the extent of its exploitation in river-reservoir transition area in Brazil. This way, from January to December 2005, different fishery catches were made with gill nets by artisanal fishermen, and a total of 426 individual H. malabaricus were obtained and sampled. From each specimen, the following biometric and biological data were analyzed: standard length, total weight, stomach contents, reproductive data such as sex, weight and gonadal maturation stage; with these data we estimated sex ratio, reproduction period and feeding habits. To assess growth parameters and infer on the degree of exploitation, the standard length frequency data were analysed using the FISAT (ELEFAN I) computer program. Data revealed a sex ratio of 0.8:1 (M:F), that reproduction occurs all year around, being more intense during spring and summer; it also showed that H. malabaricus is piscivorous. The growth parameters and mortality were estimated at: L?=35.18cm, k=0.32 year, longevity=9.3 years, Z=1.25 years, M=0.63 year and F=0.62 year. The weight-length relationship was: ln Wt=-3.1663+2.7456 ln Lp. The yield-per-recruit analysis produced the following values: E=0.496, Emax=0.916, E0.1=0.701 and E0.5=0.378. Overall, our data suggest that the stock of H. malabaricus is not yet overfished in the studied area. Rev. Biol. Trop. 59 (1): 71-83. Epub 2011 March 01.

José Luís, Costa Novaes; Edmir Daniel, Carvalho.

362

Assessing fish assemblages similarity above and below a dam in a neotropical reservoir with partial blockage.  

Science.gov (United States)

Damming rivers disrupts the water flow and changes the ichthyofauna organisation. We investigated an impoundment with permanent connection and homogeneous environmental conditions between the zones above and below the dam. Temperature was comparatively higher during wet season irrespective of zone, and both zones had higher dissolved oxygen, conductivity and transparency in the dry season. A total of 1687 individuals comprising 27 species were collected in the downriver zone, while the reservoir had 879 individuals and 23 species. Each zone had different fish assemblage composition and structure, but assemblages were not explained by the examined environmental variables (r2 = 0.08; p = 0.307). Migratory species such as Pimelodus maculatus, Pimelodus fur, Leporinus copelandii and Prochilodus lineatus were the most affected, and probably are prevented to perform upriver migrations. On the other hand, lentic adapted species such as G. brasiliensis, Hoplias malabaricus and Hoplosternum littorale successfully colonised the reservoir. Therefore we conclude that the presence of the lateral hydrological connectivity alone does not guarantee the ecological connectivity since fish assemblage similarity differed between the two zones. Fish passage facilities should be monitored and managed to evaluate and improve their functionality. PMID:24789387

Araújo, F G; Santos, A B I; Albieri, R J

2013-11-01