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Sample records for fish stock assessment

  1. Statistical aspects of fish stock assessment

    Berg, Casper Willestofte

    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...

  2. InterCatch - a tool for fish stock assessment, status and methods

    Kjems-Nielsen, Henrik; Larsen, Lena Inger; Zarecki, Maria; Jansen, Teunis; Cowan, Brian James; Sandbeck, Peter; Dueholm, Mads; Skov, Ole

    InterCatch is a web-based system for handling fish stock assessment data focusing on documenting characteristics of the catches. These national fish stock data are uploaded to InterCatch by national data submitters. After all data are uploaded the stock coordinators (working for the fish stock...... assessment group) can then check and set up allocation schemes for unsampled catches. After applying the best allocation scheme to the unsampled catches, the catch data are aggregated as required and exported for analysis, e.g. XSA or ICA....

  3. Fish Health and Fisheries, Implications for Stock Assessment and Management: The Mediterranean Example

    Lloret, J; FALIEX E.; SHULMAN G.e.; RAGA J.-A.; Sasal, P.; Muñoz, M; Casadevall, M; AHUIR-BARAJA A. E.; Montero, F. E.; REPULLÉS-ALBELDA A.; Cardinale, Massimiliano; RAETZ Hans-Joachim; S. Vila; FERRER D.

    2012-01-01

    Although fish health may influence key population-level processes, particularly those dealing with natural mortality, reproduction and growth, which in turn affect stock productivity, there has been little emphasis on the links between fish health and management of marine fisheries. This paper addresses this gap and illustrates how knowledge of fish health provides insight to marine fisheries biologists, stock assessment modellers and managers. The study demonstrates ways in which the conside...

  4. River Lune juvenile fish stock assessment 2002 (annotated draft copy, Site Reports only)

    2003-01-01

    This draft copy of the River Lune juvenile fish stock assessment from 2000 provides "Site Reports" from different water bodies in the Lune catchment. These Site Reports provide brief information on habitat features, fishery classification and comments on species caught and stocking. This document provides no summary or interpretation of the given data.

  5. Multicriteria assessment in restoring migratory fish stocks in the river Iijoki; Monitavoitearviointi Iijoen vaelluskalakantojen palauttamisen tukena

    Karjalainen, T.P.; Rytkoenen, A.-M.; Marttunen, M.; Maeki-Petaeys, A.; Autti, O.

    2011-05-15

    The Iijoki is one of Finland's most important former salmon rivers. Construction of multiple main stem dams on the river in the 1960s effectively blocked the migration corridors of migratory fish. Suitable spawning and nursery habitats above the dams span an estimated 600-800 hectares. With riverside residents are very much in favour of the return of migratory fish, watershed planning for this has been set as a target. Such measures are rendered urgent by the fact that there is still a possibility of replenishing the Iijoki's own salmon stock, thereby restoring the fishes' natural lifecycle and natural selection. This report has been completed as part of the project 'The return of migratory fish to the River Iijoki (2008-2010)', where the main object was reconciling the target of enhancing the natural life cycle of migratory fish with the continued generation of hydropower. Under a multicriteria assessment, various alternatives and measures for improving migratory fish stocks were clarified and their desirability, costs and benefits systematically and transparently evaluated. Furthermore, interest groups' views of the three options and their effects (as distinct from the expert evaluation) were clarified with the help of computer aided interviews. The alternatives were transferring salmon above the main stem dams and two fish-ladder options. The multicriteria assessment viewed the construction of fish ladders, alongside other large-scale support measures, as the best option. Based on all of the criteria applied in a cost-benefit analysis, the stock transfer alternative was the most economically viable, because its net product value was positive in all cases. The fish ladder options were the most expensive due to the construction costs involved, but they also provided the greatest benefits. Above all, fish ladder construction is supported by the fact that it would return migratory fish to their natural lifecycle and attain the EU

  6. River Lune juvenile fish stock assessment 1997 with particular reference to salmonids

    Shields, B; Clifton-Dey , D.

    2000-01-01

    This report presents data from the juvenile salmonid fish stock assessment which is part of the routine Environment Agency riverine monitoring programme. A total of 110 sites was electrofished throughout the Lune catchment between 15th July 1997 and 14th October 1997. These sites included 84 that had been previously sampled in the last comprehensive survey of the catchment, in 1991. The aim of this survey was to assess the distribution and abundance of juvenile salmon and trout in the Riv...

  7. Statistical modelling of fish stocks

    Kvist, Trine

    1999-01-01

    for modelling the dynamics of a fish population is suggested. A new approach is introduced to analyse the sources of variation in age composition data, which is one of the most important sources of information in the cohort based models for estimation of stock abundancies and mortalities. The approach combines...... and it is argued that an approach utilising stochastic differential equations might be advantagous in fish stoch assessments....

  8. Fish stock assessment under data limitations developing a new method based on a size-structured theoretical ecology framework

    Kokkalis, Alexandros

    Fish stock assessment is an integral part of every fisheries management system. Modern assessment methods require data about the fishery and the stock, such as catches, survey estimates, aging information and life history parameters, all of which is difficult and expensive to gather. However...... stocks. The model parameters correspond to Beverton-Holt life history invariants, which reduces the number of parameters and allows data-limited assessments to borrow information from data-rich stocks. The mathematical formulation of the single species population dynamics is used in a maximum......, the majority of global fish catches comes from species that lack an official assessment due to lack of data. That is true especially for small scale fisheries and fisheries in developing countries. New methods are in need that require little amount of easily attainable data and provide scientific advice...

  9. Assessing effects of stocked trout on nongame fish assemblages in southern Appalachian Mountain streams

    Weaver, D.; Kwak, Thomas J.

    2013-01-01

    Fisheries managers are faced with the challenge of balancing the management of recreational fisheries with that of conserving native species and preserving ecological integrity. The negative effects that nonnative trout species exert on native trout are well documented and include alteration of competitive interactions, habitat use, and production. However, the effects that nonnative trout may exert on nongame fish assemblages are poorly understood. Our objectives were to quantify the effects of trout stocking on native nongame fish assemblages intensively on one newly stocked river, the North Toe River, North Carolina, and extensively on other southern Appalachian Mountain streams that are annually stocked with trout. In the intensive study, we adopted a before-after, control-impact (BACI) experimental design to detect short-term effects on the nongame fish assemblage and found no significant differences in fish density, species richness, species diversity, or fish microhabitat use associated with trout stocking. We observed differences in fish microhabitat use between years, however, which suggests there is a response to environmental changes, such as the flow regime, which influence available habitat. In the extensive study, we sampled paired stocked and unstocked stream reaches to detect long-term effects from trout stocking; however, we detected no differences in nongame fish density, species richness, species diversity, or population size structure between paired sites. Our results revealed high inherent system variation caused by natural and anthropogenic factors that appear to overwhelm any acute or chronic effect of stocked trout. Furthermore, hatchery-reared trout may be poor competitors in a natural setting and exert a minimal or undetectable impact on native fish assemblages in these streams. These findings provide quantitative results necessary to assist agencies in strategic planning and decision making associated with trout fisheries, stream

  10. Fishing impact and environmental status in European seas: A diagnosis from stock assessments and ecosystem indicators

    Gascuel, Didier; Coll, Marta; Fox, Clive;

    2016-01-01

    the status and trends in fish stocks were consolidated at the ecosystem level; and (iii) trends in ecosystem indicators based on landings and surveys were analysed. We show that yields began to decrease everywhere (except in the Baltic) from the mid-1970s, as a result of the over-exploitation of some...

  11. SIS - Fish Assessment

    National Oceanic and Atmospheric Administration, Department of Commerce — The Fish Assessment data set within the Species Information System (SIS) constraints information related to fishery stock assessments, including assessment...

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

    Möllmann, Christian; Lindegren, Martin; Blenckner, Thorsten; Bergström, Lena; Casini, Michele; Diekmann, Rabea; Flinkman, Juha; Müller-Karulis, Bärbel; Neuenfeldt, Stefan; Schmidt, Jörn O.; Tomczak, Maciej; Voss, Rüdiger; Gårdmark, Anna

    2014-01-01

    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......-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...

  13. The United Nations Fish Stocks Agreement

    Juda, L.

    2002-01-01

    It is generally conceded that world marine fisheries are facing difficult times. Quantitatively world fish catch has levelled off, and qualitatively the portion of total fish catch representing high-quality, high-priced, and high-demand fish stocks is declining. A recent study indicates that fishing effort is proceeding farther down the food chain as the desired species at the top of that chain are becoming less abundant.1 While there is some discussion as to whether a...

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

    Vinther, Morten; Eero, Margit

    2013-01-01

    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 effort information and predicted stock distribution. Cod in the Kattegat is used as an example. We use...... GAM analyses to predict local cod densities and combine this with spatio-temporal data of fishing effort based on VMS (Vessel Monitoring System). To quantify local fishing impact on the stock, retention probability of the gears is taken into account. The results indicate a substantial decline in the...

  15. The true picture of a lake or reservoir fish stock: a review of needs and progress

    Kubečka, Jan; Hohausová, Eva; Matěna, Josef; Peterka, Jiří; Amarasinghe, U. S.; Bonar, S. A.; Hateley, J.; Hickley, P.; Suuronen, P.; Tereschenko, V.; Welcomme, R.; Winfield, I. J.

    2009-01-01

    Roč. 96, č. 1 (2009), s. 1-5. ISSN 0165-7836. [Fish Stock Assessment Methods for Lakes and Reservoirs: Towards the true picture of fish stock. České Budějovice, 11.09.2007-15.09.2007] Institutional research plan: CEZ:AV0Z60170517 Keywords : fish stock asessment * intercalibration * standardization * accuracy * ground truthing * interpretation * catch statistics Subject RIV: GL - Fishing Impact factor: 1.531, year: 2009

  16. Conceptual and practical advances in fish stock delineation

    Pita, Alfonso; CASEY JOHN; Stephen J Hawkins; VILLARREAL Manuel Ruiz; GUTIÉRREZ María-José; CABRAL Henrique; Carocci, Fabio; Abaunza, Pablo; Pascual, Santiago; PRESA Pablo

    2015-01-01

    The fish stock delineation concept has now evolved informed by knowledge affordable from a variety of new genetic and geochemical life cycle tracers in addition to traditional morphometric, parasitological and life history trait approaches. These can be coupled with better definition of oceanographic processes enhanced by GIS-related modelling tools. Population structure and stock delineation are central considerations for scientific assessment and strategic management in Fishery Sciences and...

  17. Stock Assessment Supplementary Information (SASINF)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the interest of efficiency, clarity and standardization of stock assessment materials, the stock assessment reports for the 2015 Groundfish update have been...

  18. Fish stocking density impacts tank hydrodynamics

    Rasmussen, Michael R.; Lunger, Angela; Laursen, Jesper;

    2006-01-01

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

  19. Influence of fish behaviour on fish stock abundance estimations

    Fréon, Pierre; Gerlotto, François

    1988-01-01

    A new methodolgy is proposed for studying fish school behaviour, allowing to quantify its influence on stock abundance estimations. Observations are collected in open sea or inside a large net set in shallow waters. Preliminary results concerning fish reactions show a modification of the school structure under a research vessel using acoustic devices for abundance measurements. The school structure, even when the fish is not disturbed, shows an irregular density distribution in opposition to ...

  20. Changing recruitment capacity in global fish stocks.

    Britten, Gregory L; Dowd, Michael; Worm, Boris

    2016-01-01

    Marine fish and invertebrates are shifting their regional and global distributions in response to climate change, but it is unclear whether their productivity is being affected as well. Here we tested for time-varying trends in biological productivity parameters across 262 fish stocks of 127 species in 39 large marine ecosystems and high-seas areas (hereafter LMEs). This global meta-analysis revealed widespread changes in the relationship between spawning stock size and the production of juvenile offspring (recruitment), suggesting fundamental biological change in fish stock productivity at early life stages. Across regions, we estimate that average recruitment capacity has declined at a rate approximately equal to 3% of the historical maximum per decade. However, we observed large variability among stocks and regions; for example, highly negative trends in the North Atlantic contrast with more neutral patterns in the North Pacific. The extent of biological change in each LME was significantly related to observed changes in phytoplankton chlorophyll concentration and the intensity of historical overfishing in that ecosystem. We conclude that both environmental changes and chronic overfishing have already affected the productive capacity of many stocks at the recruitment stage of the life cycle. These results provide a baseline for ecosystem-based fisheries management and may help adjust expectations for future food production from the oceans. PMID:26668368

  1. PIXE analysis of fish otoliths. Application to fish stock discrimination

    PIXE was adopted to analyze trace elements in otoliths of Japanese flounder to discriminate among several local fish stocks. The otoliths were removed from samples caught at five different sea areas along with the coast of the Sea of Japan: Akita, Ishikawa, Kyoto (2 stations), and Fukuoka. Besides calcium as main component, strontium, manganese, and zinc were detected. Especially Sr concentrations were different among 4 areas except between 2 stations in Kyoto. It suggested that the fish in the 2 stations in Kyoto were the same stock differed to the others. (author)

  2. PIXE analysis of fish otoliths. Application to fish stock discrimination

    Arai, Nobuaki; Sakamoto, Wataru [Kyoto Univ., Kyoto (Japan). Lab. of Fisheries and Environmental Oceanography; Tateno, Koji; Yoshida, Koji

    1996-12-31

    PIXE was adopted to analyze trace elements in otoliths of Japanese flounder to discriminate among several local fish stocks. The otoliths were removed from samples caught at five different sea areas along with the coast of the Sea of Japan: Akita, Ishikawa, Kyoto (2 stations), and Fukuoka. Besides calcium as main component, strontium, manganese, and zinc were detected. Especially Sr concentrations were different among 4 areas except between 2 stations in Kyoto. It suggested that the fish in the 2 stations in Kyoto were the same stock differed to the others. (author)

  3. Aeromonas salmonicida infection levels in pre- and post-stocked cleaner fish assessed by culture and an amended qPCR assay.

    Gulla, S; Duodu, S; Nilsen, A; Fossen, I; Colquhoun, D J

    2016-07-01

    Due to increasing resistance to chemical therapeutants, the use of 'cleaner fish' (primarily wrasse, Labridae, species) has become popular in European salmon farming for biocontrol of the salmon louse, Lepeophtheirus salmonis (Krøyer). While being efficient de-licers, cleaner fish mortality levels in salmon cages are commonly high, and systemic bacterial infections constitute a major problem. Atypical furunculosis, caused by Aeromonas salmonicida A-layer types V and VI, is among the most common diagnoses reached in clinical investigations. A previously described real-time PCR (qPCR), targeting the A. salmonicida A-layer gene (vapA), was modified and validated for specific and sensitive detection of all presently recognized A-layer types of this bacterium. Before stocking and during episodes of increased mortality in salmon cages, cleaner fish (primarily wild-caught wrasse) were sampled and screened for A. salmonicida by qPCR and culture. Culture indicated that systemic bacterial infections are mainly contracted after salmon farm stocking, and qPCR revealed A. salmonicida prevalences of approximately 4% and 68% in pre- and post-stocked cleaner fish, respectively. This underpins A. salmonicida's relevance as a contributing factor to cleaner fish mortality and emphasizes the need for implementation of preventive measures (e.g. vaccination) if current levels of cleaner fish use are to be continued or expanded. PMID:26514414

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

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

    2015-01-01

    The World Conference on Stock Assessment Methods (July 2013) included a workshop on testing assessment methods through simulations. The exercise was made up of two steps applied to datasets from 14 representative fish stocks from around the world. Step 1 involved applying stock assessments to dat...

  5. Fish otoliths analysis by PIXE: application to stock discrimination

    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)

  6. Fish otoliths analysis by PIXE: application to stock discrimination

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

    1996-12-31

    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)

  7. Biological reference points for fish stocks in a multispecies context

    Collie, J.S.; Gislason, Henrik

    2001-01-01

    variation. For a prey species like sprat, fishing mortality reference levels should be conditioned on the level of predation 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...

  8. The future prospects of the fish stocks of Lake Victoria, Uganda

    Okaronon, J.O.

    1990-01-01

    Experimental trawling during the period 1981/86 and analysis of past commercial catch landings, mainly in the northern portion of Lake Victoria have indicated that the standing stocks and therefore, the estimates of sustainable yields of the most important fish species have unquestionably changed since the 1969/71 comprehensive lake-wide stock assessment survey. Lake Victoria which was originally a multi-species fishery now relies on two introduced species (Lates niloticus and Ore...

  9. Assessment and management of flatfish stocks

    Cadrin, S.X.; Clark, W.G.; Ricard, Daniel

    2. Wiley Blackwell, 2015 - (Gibson, R.; Nash, R.; Geffen, A.; VanDerVeer, H.), s. 461-490 ISBN 978-111850115-3;978-111850119-1 Institutional support: RVO:60077344 Keywords : flatfish * stock assessment * fishery management * population dynamics * stock-recruitment relationships * stock status Subject RIV: EH - Ecology, Behaviour

  10. Intelligent Fish Freshness Assessment

    Deena Benjamin

    2008-04-01

    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%.

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

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

    2012-01-01

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

  12. Comparing proactive and reactive management: Managing a transboundary fish stock under changing environment

    Liu, X.; Heino, M.

    2012-01-01

    Environmental change in general, and climate change in particular, can lead to changes in distribution of fish stocks. When such changes involve transboundary fish stocks, the countries sharing the stock need to reconsider their harvesting policies. We investigate the effects of changing stock distribution on the optimal fishing policies in a two players' non-cooperative game. We compare reactive management, under which the manager ignores future distributional shifts (knowingly or unknowingl...

  13. Topmouth gudgeon Pseudorasbora parva: a side effect of fish stocking

    Michał Nowak

    2009-12-01

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

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

    Dodson, Guy; Pero, Vincent

    2002-01-01

    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).

  15. Limits to the reliability of size-based fishing status estimation for data-poor stocks

    Kokkalis, Alexandros; Thygesen, Uffe Høgsbro; Nielsen, Anders;

    2015-01-01

    For stocks which are considered “data-poor” no knowledge exist about growth, mortality or recruitment. The only available information is from catches. Here we examine the ability to assess the level of exploitation of a data-poor stock based only on information of the size of individuals in catches....... The model is a formulation of the classic Beverton–Holt theory in terms of size where stock parameters describing growth, natural mortality, recruitment, etc. are determined from life-history invariants. A simulation study was used to compare the reliability of assessments performed under different...... information availability scenarios, from data-limited, where none of the parameters are known beforehand, to different degrees of information availability cases where one or more parameters are known. If no parameters are known it is possible to correctly assess whether the fishing mortality is below Fmsy...

  16. Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

    He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

    2015-01-01

    We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

  17. Eastern Baltic cod in distress: biological changes and challenges for stock assessment

    Eero, Margit; Hjelm, Joakim; Behrens, Jane;

    2015-01-01

    The eastern Baltic (EB) cod (Gadus morhua) stock was depleted and overexploited for decades until the mid-2000s, when fishing mortality rapidly declined and biomass started to increase, as shown by stock assessments. These positive developments were partly assigned to effective management measures...

  18. An Applied Framework for Incorporating Multiple Sources of Uncertainty in Fisheries Stock Assessments

    Scott, Finlay; Jardim, Ernesto; Millar, Colin P.; Cerviño, Santiago

    2016-01-01

    Estimating fish stock status is very challenging given the many sources and high levels of uncertainty surrounding the biological processes (e.g. natural variability in the demographic rates), model selection (e.g. choosing growth or stock assessment models) and parameter estimation. Incorporating multiple sources of uncertainty in a stock assessment allows advice to better account for the risks associated with proposed management options, promoting decisions that are more robust to such uncertainty. However, a typical assessment only reports the model fit and variance of estimated parameters, thereby underreporting the overall uncertainty. Additionally, although multiple candidate models may be considered, only one is selected as the ‘best’ result, effectively rejecting the plausible assumptions behind the other models. We present an applied framework to integrate multiple sources of uncertainty in the stock assessment process. The first step is the generation and conditioning of a suite of stock assessment models that contain different assumptions about the stock and the fishery. The second step is the estimation of parameters, including fitting of the stock assessment models. The final step integrates across all of the results to reconcile the multi-model outcome. The framework is flexible enough to be tailored to particular stocks and fisheries and can draw on information from multiple sources to implement a broad variety of assumptions, making it applicable to stocks with varying levels of data availability The Iberian hake stock in International Council for the Exploration of the Sea (ICES) Divisions VIIIc and IXa is used to demonstrate the framework, starting from length-based stock and indices data. Process and model uncertainty are considered through the growth, natural mortality, fishing mortality, survey catchability and stock-recruitment relationship. Estimation uncertainty is included as part of the fitting process. Simple model averaging is used

  19. AFSC/REFM: Alaska Stock Assessment Results Archive (SARA)

    National Oceanic and Atmospheric Administration, Department of Commerce — Each year over 50 Alaskan groundfish stock assessments report the condition of Alaskan fisheries resources in the U.S. Exclusive Economic Zone. Stock assessment...

  20. Can accidental introductions of non-native species be prevented by fish stocking audits ?

    Davies, G. D.; Gozlan, Rodolphe; Britton, J R

    2013-01-01

    Accidental introductions of non-native species into aquatic environments often result in invasive populations that cause substantial conservation concerns. They account for 8% of all fish introductions and often occur when fish consignments are intentionally released into the wild (stocked') but are unknowingly contaminated with a hitch-hiking' species that is also released.This study tested the efficacy of a fish stocking audit procedure in preventing the introduction of a model hitch-hiking...

  1. A note on the development of a new software package, the FAO-ICLARM stock assessment tools (FiSAT)

    Pauly, D.; Sparre, P.

    1991-01-01

    A brief narrative is given of the background of a new FAO-ICLARM software for (mainly length-based) fish stock assessment, the FAO-ICLARM Stock Assessment Tools or "FiSAT" package, integrating the ICLARM's Compleat ELEFAN, FAO's LFSA and various other routines, and which is to be released in mid-1992.

  2. 77 FR 47043 - Draft 2012 Marine Mammal Stock Assessment Reports

    2012-08-07

    ... National Oceanic and Atmospheric Administration RIN 0648-XC062 Draft 2012 Marine Mammal Stock Assessment..., and Pacific regional marine mammal stock assessment reports (SARs) in accordance with the Marine..., Silver Spring, MD 20910-3226, Attn: Stock Assessments. Instructions: All comments received are a part...

  3. Swimming Performance Assessment in Fishes

    Keith B Tierney

    2011-01-01

    Swimming performance tests of fish have been integral to studies of muscle energetics, swimming mechanics, gas exchange, cardiac physiology, disease, pollution, hypoxia and temperature. This paper describes a flexible protocol to assess fish swimming performance using equipment in which water velocity can be controlled. The protocol involves one to several stepped increases in flow speed that are intended to cause fish to fatigue. Step speeds and their duration can be set to capture swimming ...

  4. Sushi or fish fingers? Seafood diversity, collapsing fish stocks, and multi-species fishery management

    Quaas, Martin F.; Requate, Till

    2012-01-01

    We present a model of a multi-species fishery and show that (i) consumer preferences for seafood diversity may trigger a sequential collapse of fish stocks under open-access fishery, (ii) the stronger the preferences are for diversity the higher is the need for coordinated multi-species regulation, (iii) second-best optimal management of only one (or a few) species is less strict than socially optimal management of the same species. Finally, (iv) myopic regulation of one species, ignoring spi...

  5. Changes in the fish community and water quality during seven years of stocking piscivorous fish in a shallow lake

    Skov, Christian; Perrow, M.R.; Berg, Søren; Skovgaard, H.

    2002-01-01

    zooplanktivorous and benthivorous fish, with resultant effects on lower trophic levels and ultimately water quality. 2. The fish community and water quality parameters (Secchi depth, concentrations of total phosphorus, chlorophyll a and suspended solids) were monitored between 1996 and 2000 and relationships were...... evaluated between predatory fish and potential prey and between zooplanktivorous or benthivorous fish and water quality parameters. In addition, potential consumption of piscivorous fishes was calculated. 3. The density of fish feeding on larger zooplankton or benthos (roach >15 cm, crucian carp >15 cm......) declined distinctly during the study period. This effect was attributed to predation by large (>50 cm) pike. Based on scale readings, we cautiously suggest that the stocking of 0+ pike boosted the adult pike population to produce an unexpected impact in later years. Conversely, no direct impact of stocked...

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

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

    2003-09-01

    In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area

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

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

    2003-01-01

    In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power Planning Council (NPPC). The NPPC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPPC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area and the Columbia Basin Blocked Area Management Plan

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

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

    2006-02-01

    In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial and native fish assemblages in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area. The

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

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

    2005-11-01

    In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation of hydroelectric dams in the Columbia River Basin. In developing the FWP, Congress specifically directed NPCC to solicit recommendations for measures to be included in the Program from the region's fish and wildlife agencies and Indian tribes. All measures adopted by the Council were also required to be consistent with the management objectives of the agencies and tribes [Section 4.(h)(6)(A)], the legal rights of Indian tribes in the region [Section 4.(h)(6)(D)] and be based upon and supported by the best available scientific knowledge [Section 4.(h)(6)(B)]. The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, also known as the Joint Stock Assessment Project (JSAP) specifically addresses NPPC Council measure 10.8B.26 of the 1994 program. The Joint Stock Assessment Project is a management tool using ecosystem principles to manage artificial and native fish assemblages in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (Blocked Area). A three-phase approach of this project will enhance the fisheries resources of the Blocked Area by identifying data gaps, filling data gaps with research, and implementing management recommendations based on research results. The Blocked Area fisheries information is housed in a central location, allowing managers to view the entire system while making decisions, rather than basing management decisions on isolated portions of the system. The JSAP is designed and guided jointly by fisheries managers in the Blocked Area. The

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

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

    2001-01-01

    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 f...

  11. 78 FR 66681 - Draft 2013 Marine Mammal Stock Assessment Reports

    2013-11-06

    ... seals and ringed seals as ``threatened'' under the Endangered Species Act (77 FR 76740). Because of the... National Oceanic and Atmospheric Administration RIN 0648-XC853 Draft 2013 Marine Mammal Stock Assessment... Pacific regional marine mammal stock assessment reports (SARs) in accordance with the Marine...

  12. Brown trout habitat assessment on the River Bela catchment (as recommended by the strategic fisheries stock assessment task group 1995)

    Watson, E.P.K.; McCubbing, D.J.F.

    1997-01-01

    This is the Brown trout habitat assessment on the River Bela catchment produced by the Environment Agency North West in 1997. The Environment Agency (EA) and its predecessor the National Rivers Authority undertook strategic fish stock assessments in 1992 and 1995 on the River Bela catchment. These surveys found low numbers of brown trout {Salmo trutta) at some sites. Following this, habitat evaluation assessments were undertaken on the eleven poorest sites Factors probably responsible for dec...

  13. 77 FR 29969 - Marine Mammal Stock Assessment Reports

    2012-05-21

    ... stock assessment guidelines. Response: NMFS has previously responded to this comment (see 76 FR 34054... comment for 90 days (76 FR 52940, August 24, 2011). NMFS received comments on the draft SARs and has... rates for every stock. Response: NMFS has previously responded to this comment (see 76 FR 34054, June...

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

    Ross, Stine Dalmann; Hüssy, Karin

    2013-01-01

    Accurate age estimation is important for stock assessment and management. The importance of reliable ageing is emphasized by the impending analytical assessment of whiting (Merlangius merlangus) in the Baltic Sea. Whiting is a top predator in the western Baltic Sea, where it is fished commercially...... the subsequent winter rings. Microstructure analysis was used to confirm the 1st winter ring. Additionally, otolith growth trajectories were obtained, confirming the allometric growth as seen in many fish species. The method for ageing of whole otoliths presented in this study can be directly...

  15. Current status of the fish stocks of Lake Victoria (Uganda)

    Okaronon, J.O.; Muhoozi, L.; Bassa, S.

    1999-01-01

    A total of 457 hauls were taken during experimental bottom trawl surveys in the Uganda sector of Lake Victoria between November 1997 and June 1999 to estimate composition, distribution and abundance of the major fish species in waters 4-60 m deep. Fifteen fish groups were caught with Nile perch, Lates niloticus (L.), constituting 94% by weight. Haplochromines and L. niloticus occurred in all areas sampled, while Nile tilapia, Oreochromis niloticus (L.) and other tilapiines were restricted to ...

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

    Holmlund, Cecilia M; Hammer, Monica

    2004-06-01

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

  17. (Flat)fish stocks in an ecosystem and evolutionary perspective

    Volckaert, Filip

    2013-01-01

    The delineation of natural populations has many faces. While a stock relates to a management unit of organisms, the biological concept of a population may relate to a demographic/ecological perspective on interacting organisms or an evolving group of organisms. In addition, it has become increasingly clear that the time and spatial scales of the ecological and evolutionary population have much in common. Evolutionary population models, which are the focus of this paper, harbor independent inf...

  18. The assessment and exploitation of eel (ANGUILLA ANGUILLA. L) stocks in the River Thames and its catchment.

    1986-01-01

    This is the assessment and exploitation of eel (Anguilla anguilla. L) stocks in the River Thames and its catchment performed by the Polytechnic of Central London and The Thames Water Authority Research Project between April 1985 and April 1986. The report makes an examination of the pre-pollution history of the Thames eel fishing industry to permit an assessment of the recovery of the eel stock following the cleaning up of the Tideway. Archive material shows that the 19th Century stock was la...

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

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar; Mensberg, Karen-Lise Dons

    2001-01-01

    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...... 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...

  20. Spatially-Resolved Influence of Temperature and Salinity on Stock and Recruitment Variability of Commercially Important Fishes in the North Sea.

    Akimova, Anna; Núñez-Riboni, Ismael; Kempf, Alexander; Taylor, Marc H

    2016-01-01

    Understanding of the processes affecting recruitment of commercially important fish species is one of the major challenges in fisheries science. Towards this aim, we investigated the relation between North Sea hydrography (temperature and salinity) and fish stock variables (recruitment, spawning stock biomass and pre-recruitment survival index) for 9 commercially important fishes using spatially-resolved cross-correlation analysis. We used high-resolution (0.2° × 0.2°) hydrographic data fields matching the maximal temporal extent of the fish population assessments (1948-2013). Our approach allowed for the identification of regions in the North Sea where environmental variables seem to be more influential on the fish stocks, as well as the regions of a lesser or nil influence. Our results confirmed previously demonstrated negative correlations between temperature and recruitment of cod and plaice and identified regions of the strongest correlations (German Bight for plaice and north-western North Sea for cod). We also revealed a positive correlation between herring spawning stock biomass and temperature in the Orkney-Shetland area, as well as a negative correlation between sole pre-recruitment survival index and temperature in the German Bight. A strong positive correlation between sprat stock variables and salinity in the central North Sea was also found. To our knowledge the results concerning correlations between North Sea hydrography and stocks' dynamics of herring, sole and sprat are novel. The new information about spatial distribution of the correlation provides an additional help to identify mechanisms underlying these correlations. As an illustration of the utility of these results for fishery management, an example is provided that incorporates the identified environmental covariates in stock-recruitment models. PMID:27584155

  1. Assessment of potential oil pollution damages on fish resources. Some examples from the area outside mid-Norway

    Føyn, Lars; Bjørke, Herman

    1987-01-01

    Detailed mapping of fish eggs and larvae both in space and time is essential knowledge when realistic assessments of oil pollution damages to the fish resources are established. The text explain with some examples our attempts to determine how and if pollution from oil fields outside mid-Norway may affect fish stocks.

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

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

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

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

    2001-01-01

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

  4. Stock assessment of fishery target species in Lake Koka, Ethiopia.

    Tesfaye, Gashaw; Wolff, Matthias

    2015-09-01

    Effective management is essential for small-scale fisheries to continue providing food and livelihoods for households, particularly in developing countries where other options are often limited. Studies on the population dynamics and stock assessment on fishery target species are thus imperative to sustain their fisheries and the benefits for the society. In Lake Koka (Ethiopia), very little is known about the vital population parameters and exploitation status of the fishery target species: tilapia Oreochromis niloticus, common carp Cyprinus carpio and catfish Clarias gariepinus. Our study, therefore, aimed at determining the vital population parameters and assessing the status of these target species in Lake Koka using length frequency data collected quarterly from commercial catches from 2007-2012. A total of 20,097 fish specimens (distributed as 7,933 tilapia, 6,025 catfish and 6,139 common carp) were measured for the analysis. Von Bertalarffy growth parameters and their confidence intervals were determined from modal progression analysis using ELEFAN I and applying the jackknife technique. Mortality parameters were determined from length-converted catch curves and empirical models. The exploitation status of these target species were then assessed by computing exploitation rates (E) from mortality parameters as well as from size indicators i.e., assessing the size distribution of fish catches relative to the size at maturity (Lm), the size that provides maximum cohort biomass (Lopt) and the abundance of mega-spawners. The mean value of growth parameters L∞, K and the growth performance index ø' were 44.5 cm, 0.41/year and 2.90 for O. niloticus, 74.1 cm, 0.28/year and 3.19 for C. carpio and 121.9 cm, 0.16/year and 3.36 for C. gariepinus, respectively. The 95 % confidence intervals of the estimates were also computed. Total mortality (Z) estimates were 1.47, 0.83 and 0.72/year for O. niloticus, C. carpio and C. gariepinus, respectively. Our study suggest that

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

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

    2009-05-11

    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

  6. A High-Speed Fish Evisceration System (FES) for Bycatch and Underutilized Fish Stocks

    Nicklason, Peter M.; Barnett, Harold; Babbitt, Jerry K.

    2012-01-01

    Development of a high-speed and high-yield water-powered fish evisceration system (FES) to efficiently preprocess small fish and bycatch for producing minced fish meat is described. The concept of the system is propelling fish in a stream of water through an arrangement of cutting blades and brushes. Eviscerated fish are separated from the viscera and water stream in a dual screen rotary sieve. The FES processed head off fish, weighing 170–500 g, at the rate of 300 fish/min when used with an ...

  7. Resilience and Critical Stock Size in a Stochastic Recruitment Model

    Grasman, J.; Huiskes, M.J.

    2001-01-01

    A stochastic model for fish recruitment is fitted to data after performing an age-structured stock assessment. The main aim is to investigate the relation between safe levels of spawning stock size and fish stock resilience. Resilience indicators, such as stock recovery time and the frequency that a

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

    Bartolino, V.; Margonski, P.; Lindegren, Martin;

    2014-01-01

    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...

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

    Hansen, Michael Møller; Eg Nielsen, Einar; Bekkevold, Dorte;

    2001-01-01

    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...

  10. Assessments to determine the effect of current and alternate ladder operations on brood stock collection and behavior of hatchery fall Chinook Salmon at Little White Salmon National Fish Hatchery during 2004-05

    US Fish and Wildlife Service, Department of the Interior — Production of upriver bright fall Chinook salmon at Little White Salmon National Fish Hatchery was introduced as part of the John Day Dam mitigation program in the...

  11. Assessments to determine the effect of current and alternate ladder operations on brood stock collection and behavior of hatchery fall Chinook Salmon at Spring Creek National Fish Hatchery during 2003-2005

    US Fish and Wildlife Service, Department of the Interior — Spring Creek National Fish Hatchery traditionally operates an adult ladder, without closure, from the start of the tule fall Chinook salmon run in late August until...

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

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

    2009-05-11

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

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

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

    2009-02-20

    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

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

    Jacobsen, A. Lif Lund

    2005-01-01

    In 1985, T.W. Gallant published an influential essay on the potential productivity of fishing in the ancient world. He concluded that: ”the role of fishing in the diet and economy would have been, on the whole, subordinate and supplementary…” His methodological approach was original in using modern...

  15. 75 FR 6058 - Federal Sport Fish Restoration; California Department of Fish and Game Fish Hatchery and Stocking...

    2010-02-05

    ... the Federal Register on August 5, 2008 (73 FR 45470). The notice of availability for the draft EIR/EIS and 45-day comment period published in the Federal Register on October 8, 2009 (74 FR 51872). The... Fish and Wildlife Service Federal Sport Fish Restoration; California Department of Fish and Game...

  16. The response of stock prices to dividend news on the Ghana stock market: An empirical assessment

    Gideon Boako

    2015-01-01

    An important assumption of the signaling hypothesis is that dividend change announcements are positively correlated with share price reactions and future changes in earnings. However, Miller and Modigliani (1961)sustains that, dividend policy is irrelevant in arriving at a firm value, if the capital market is perfect. The purpose of this paper is to assess the potency of the dividend irrelevance theory on the Ghana stock market by using the Johansen-Juselius cointegration methodology on daily...

  17. Portfolio theory as a management tool to guide conservation and restoration of multi-stock fish populations

    DuFour, Mark R.; May, Cassandra J.; Roseman, Edward F.; Ludsin, Stuart A.; Vandergoot, Christopher S.; Pritt, Jeremy J.; Fraker, Michael E.; Davis, Jeremiah J.; Tyson, Jeffery T.; Miner, Jeffery G.; Marschall, Elizabeth A.; Mayer, Christine M.

    2015-01-01

    Habitat degradation and harvest have upset the natural buffering mechanism (i.e., portfolio effects) of many large-scale multi-stock fisheries by reducing spawning stock diversity that is vital for generating population stability and resilience. The application of portfolio theory offers a means to guide management activities by quantifying the importance of multi-stock dynamics and suggesting conservation and restoration strategies to improve naturally occurring portfolio effects. Our application of portfolio theory to Lake Erie Sander vitreus (walleye), a large population that is supported by riverine and open-lake reef spawning stocks, has shown that portfolio effects generated by annual inter-stock larval fish production are currently suboptimal when compared to potential buffering capacity. Reduced production from riverine stocks has resulted in a single open-lake reef stock dominating larval production, and in turn, high inter-annual recruitment variability during recent years. Our analyses have shown (1) a weak average correlation between annual river and reef larval production (ρ̄ = 0.24), suggesting that a natural buffering capacity exists in the population, and (2) expanded annual production of larvae (potential recruits) from riverine stocks could stabilize the fishery by dampening inter-annual recruitment variation. Ultimately, our results demonstrate how portfolio theory can be used to quantify the importance of spawning stock diversity and guide management on ecologically relevant scales (i.e., spawning stocks) leading to greater stability and resilience of multi-stock populations and fisheries.

  18. Assessing changes in amphibian population dynamics following experimental manipulations of introduced fish.

    Pope, Karen L

    2008-12-01

    Sport-fish introductions are now recognized as an important cause of amphibian decline, but few researchers have quantified the demographic responses of amphibians to current options in fisheries management designed to minimize effects on sensitive amphibians. Demographic analyses with mark-recapture data allow researchers to assess the relative importance of survival, local recruitment, and migration to changes in population densities. I conducted a 4-year, replicated whole-lake experiment in the Klamath Mountains of northern California (U.S.A.) to quantify changes in population density, survival, population growth rate, and recruitment of the Cascades frog (Rana cascadae) in response to manipulations of non-native fish populations. I compared responses of the frogs in lakes where fish were removed, in lakes in their naturally fish-free state, and in lakes where fish remained that were either stocked annually or no longer being stocked. Within 3 years of fish removals from 3 lakes, frog densities increased by a factor of 13.6. The survival of young adult frogs increased from 59% to 94%, and realized population growth and recruitment rates at the fish-removal lakes were more than twice as high as the rates for fish-free reference lakes and lakes that contained fish. Population growth in the fish-removal lakes was likely due to better on-site recruitment of frogs to later life stages rather than increased immigration. The effects on R. cascadae of suspending stocking were ambiguous and suggested no direct benefit to amphibians. With amphibians declining worldwide, these results show that active restoration can slow or reverse the decline of species affected by fish stocking within a short time frame. PMID:18680499

  19. Micro-PIXE analysis of fish otoliths. Methodology and evaluation of first results for stock discrimination

    Micro-PIXE has been used to measure the trace element distribution in otoliths from several species of ocean fish, in order to investigate its possible use in stock discrimination. Trace elements detected include Sr, Fe, Mn, Ni, Zn, Cu, Se, Cd, Br, Hg and Pb. Trace elements Na, K, Cl, S and Cl were detected with the electron microprobe. The high sensitivity of PIXE demands a meticulous sample preparation procedure to avoid contamination problems. Practical problems associated with the application of the technique were investigated in detail. Preliminary results indicate that most trace elements except Sr, are present at close to the limits of detection at few ppm, but biologically significant data can be obtained for stock discrimination applications. (author)

  20. Micro-PIXE analysis of fish otoliths. Methodology and evaluation of first results for stock discrimination

    Sie, S.H. [Commonwealth Scientific and Industrial Research Organization, North Ryde, NSW (Australia). Div. of Exploration Geoscience; Thresher, R.E.

    1992-12-31

    Micro-PIXE has been used to measure the trace element distribution in otoliths from several species of ocean fish, in order to investigate its possible use in stock discrimination. Trace elements detected include Sr, Fe, Mn, Ni, Zn, Cu, Se, Cd, Br, Hg and Pb. Trace elements Na, K, Cl, S and Cl were detected with the electron microprobe. The high sensitivity of PIXE demands a meticulous sample preparation procedure to avoid contamination problems. Practical problems associated with the application of the technique were investigated in detail. Preliminary results indicate that most trace elements except Sr, are present at close to the limits of detection at few ppm, but biologically significant data can be obtained for stock discrimination applications. (author).

  1. Unintentional selection, unanticipated insights: introductions, stocking and the evolutionary ecology of fishes.

    Hutchings, J A

    2014-12-01

    Natural environmental change has produced countless opportunities for species to disperse into and persist in habitats where they previously did not exist. Introduction and stocking programmes have facilitated similar sorts of colonization opportunities across considerably greater geographical scales and often in much shorter periods of time. Even though the mechanism of colonization differs, the result can be the same: evolutionary change in the colonizing population in response to novel selection pressures. As a consequence, some human-mediated fish transfers have unintentionally yielded novel research opportunities to study how phenotypes and genes interact with their environment and affect ecological and evolutionary change. The primary purpose here is to explore how work, directly or indirectly involved with human-mediated transfers, has unintentionally yielded novel research and research opportunities in fish ecology and evolution. Insights have produced new knowledge or altered previously held perceptions on topics such as local adaptation, rate of evolutionary change, phenotypic plasticity, alternative reproductive strategies, population structure and colonization probability. Well-documented stocking programmes, especially in terms of history, numbers and original population sources, can provide highly fertile ground for generating further insights on the ecology and evolution of fishes and of the factors likely to influence the success of conservation-based, restoration programmes. PMID:25469951

  2. AFSC: Various fish maturity studies

    National Oceanic and Atmospheric Administration, Department of Commerce — Knowledge of the reproductive biology of fish and crab stocks is critical to stock assessment estimates of the reproductive potential (typically measured as...

  3. The response of stock prices to dividend news on the Ghana stock market: An empirical assessment

    Gideon Boako

    2015-04-01

    Full Text Available An important assumption of the signaling hypothesis is that dividend change announcements are positively correlated with share price reactions and future changes in earnings. However, Miller and Modigliani (1961sustains that, dividend policy is irrelevant in arriving at a firm value, if the capital market is perfect. The purpose of this paper is to assess the potency of the dividend irrelevance theory on the Ghana stock market by using the Johansen-Juselius cointegration methodology on daily data of dividends, earnings and stock prices from January 2011 to December 2013. The results establish that equity prices in Ghana are not in sync with dividend announcements. However, the incorporation of earnings in the cointegration model provides varying result. The findings indicate that equity price change movements in Ghana are not responsive to dividend news.

  4. Analyzing fish stocks dynamics using CPUE and PRCF:a new approach for the fishery management

    G Vzquez-Prada

    2014-01-01

    Catch per unit effort has been used in many fisheries researches worldwide like an abundance or density index. Parallel to this issue, partial ratio correlation function is a technique used to identify the density dependent structure underlying ecological time series. Although partial ratio correlation function is widely used in ecological fields, it has not been much used in fisheries and aquatic sciences. In this synthesis, a new combination of statistical techniques is proposed to diagnose the order of the population dynamic of fish stocks, as the first knowledge of the type of factors that may be regulating them, included human predation as an exogenous factor.

  5. Characterizing the trophic niches of stocked and resident cyprinid fishes: consistency in partitioning over time, space and body sizes.

    Bašić, Tea; Britton, J Robert

    2016-07-01

    Hatchery-reared fish are commonly stocked into freshwaters to enhance recreational angling. As these fishes are often of high trophic position and attain relatively large sizes, they potentially interact with functionally similar resident fishes and modify food-web structure. Hatchery-reared barbel Barbus barbus are frequently stocked to enhance riverine cyprinid fish communities in Europe; these fish can survive for over 20 years and exceed 8 kg. Here, their trophic consequences for resident fish communities were tested using cohabitation studies, mainly involving chub Squalius cephalus, a similarly large-bodied, omnivorous and long-lived species. These studies were completed over three spatial scales: pond mesocosms, two streams and three lowland rivers, and used stable isotope analysis. Experiments in mesocosms over 100 days revealed rapid formation of dietary specializations and discrete trophic niches in juvenile B. barbus and S. cephalus. This niche partitioning between the species was also apparent in the streams over 2 years. In the lowland rivers, where fish were mature individuals within established populations, this pattern was also generally apparent in fishes of much larger body sizes. Thus, the stocking of these hatchery-reared fish only incurred minor consequences for the trophic ecology of resident fish, with strong patterns of trophic niche partitioning and diet specialization. Application of these results to decision-making frameworks should enable managers to make objective decisions on whether cyprinid fish should be stocked into lowland rivers according to ecological risk. PMID:27547336

  6. 17 CFR 230.136 - Definition of certain terms in relation to assessable stock.

    2010-04-01

    ... relation to assessable stock. 230.136 Section 230.136 Commodity and Securities Exchanges SECURITIES AND... certain terms in relation to assessable stock. (a) An offer, offer to sell, or offer for sale of... shall not be deemed to include the offering or sale of assessable stock, at public auction or...

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

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

    2003-03-01

    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.

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

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

    2011-06-01

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

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

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

    2004-02-01

    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

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

    Lewis, Mark; Mallette, Christine; Murray, William

    2002-03-01

    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.

  11. Status and trends of the major roundfish, flatfish, and pelagic fish stocks in the North Sea : Thirty-year overview

    Serchuk, F.M.; Kirkegaard, Eskild; Daan, N.

    1996-01-01

    Changes in the status of the major roundfish, flatfish, and pelagic stocks in the North Sea over the past 30 years are reviewed. Synopses are presented on trends in catches, fishing mortality, spawning-stock biomass, and recruitment for eight stocks (cod, haddock, whiting, saithe, plaice, sole......, herring, and mackerel), together with an evaluation of the current state of these resources and the most resent management advice provided by the ICES Advisory, Committee on Fishery Management. (C) 1996 International Council for the Exploration of the Sea...

  12. Stocking of Offsite Waters for Hungry Horse Dam Mitigation Creston National Fish Hatchery, FY 2006 Annual Report.

    Hooley, Sharon

    2009-03-20

    A total of 350,000, M012 strain, westslope cutthroat trout (WCT) eggs were received from Montana Fish Wildlife & Parks (MFWP), Washoe Park State Fish Hatchery in June of 2005 to accomplish this fishery management objective. These eggs were incubated, hatched and reared entirely inside the hatchery nursery building using a protected well water supply. Fish grew according to schedule and survival was excellent. The hatchery achieved a 0.78 feed fed to pounds gained conversion ratio for this group of WCT. Not all of the progenies from this fish lot were used for Hungry Horse Dam Fishery Mitigation Implementation. Some were used for other regional fishery management projects. Westslope cutthroat trout were reared using approved fish culture techniques as recommended in the USFWS Fish Hatchery Management Handbook and also utilizing a regimen adapted for hatchery specific site conditions. The fish health for these WCT was very good. Survival from first feeding fry stage to stocking was 79%. The hatchery had an annual fish health inspection performed by the USFWS Bozeman Fish Health Center in mid March of 2006. This inspection found all fish lots at Creston to be disease free. The Montana State Fish Health Board has placed the hatchery under a limited quarantine since May of 2005 due to an epizootic of Furunculosis. This classification has allowed the Creston NFH to stock disease free fish in locations approved by regional fish managers. The hatchery has been working with the State Fish Pathologist to remove the limited quarantine classification from the facility. Although fish health for all station fish lots remains disease free, MFWP has asserted it will not remove the limited quarantine until the new influent water treatment system, including the ultraviolet disinfection unit, is running full time, year round. The USFWS is working to secure the additional funding necessary to operate the treatment building year round. Distribution of the WCT took place from March

  13. Implications of fisheries during the spawning season for the sustainable management and recovery of depleted fish stocks: a conceptual framework

    Rijnsdorp, A. D.

    2009-01-01

    Fishing during the spawning season may negatively affects the reproductive potential and reproductive dynamics of exploited fish stocks due to a variety of mechanisms such as the disturbance of the natural spawning behaviour, effects on the age, size and sex composition of the spawning population and effects on the population genetics. The effect may differ between species in relation to the spawning strategy and population dynamic characteristics. Based on first principles of reproductive bi...

  14. Spawner-recruit relationships and fish stock carrying capacity in aquatic ecosystems

    MacKenzie, Brian; Myers, R.A.; Bowen, K.G.

    2003-01-01

    Few marine ecologists have addressed important questions about the relative productivity and carrying capacity of different ecosystems required to support fish populations. Whereas many researchers have investigated interannual variability in recruitment within a stock, we asked whether...... the spawner-recruit relationship is examined among populations of the same species. The slopes of these relationships are close to 1 (i.e. proportional). However, mean recruitment per spawner varies greatly among species (range 3 to 10). Some ecosystems allowed cod Gadus morhua, haddock Melanogrammus...... aeglefinus and herring Clupea harengus populations to produce an average of ca. 8-fold more recruits per spawner than other ecosystems. Also, the abundance of at least 1 species (cod) is strongly related to habitat size. Reasons for the differences in recruit production per spawner between ecosystems are...

  15. Rebuilding EU fish stocks could generate substantial financial resources for the European economy

    Villasante, Sebastian; Sumaila, Rashid

    2013-01-01

    On 6 February, the European Parliament voted in favour of proposals to reform the EU’s Common Fisheries Policy. Sebastian Villasante and Rashid Sumaila assess the problem posed by overfishing in Europe’s waters and outline some of the key areas which need to be addressed if the Common Fisheries Policy is to achieve its aim of ensuring sustainable fishing.

  16. Greenland Halibut in Upernavik: a preliminary study of the importance of the stock for the fishing populace

    Delaney, Alyne E.; Becker Jakobsen, Rikke; Hendriksen, Kåre

    for residents. Consequently, it is important to understand the adaptability and vulnerability of the community in order to successfully anticipate impacts. Greenland halibut is the most important commercial fish stock for Upernavik residents. In 2010 there were more than 385 fishermen with official...... Greenland is currently in the midst of proposing changes to the Halibut management structure, the report focuses specifically on potential social impacts of the fishery management plan to coastal fishers. The degree and consequence of any impact is a function of the characteristics of the fishing community...... licenses for Greenland halibut in Upernavik. There are up to an additional 75 who also fish, however, without paying the license fee. This means that almost half of working age men fish for halibut in the Upernavik district. Fishing is extremely important in Upernavik for its role in the local, mixed...

  17. Life history inhomogeneity in Baltic Sea whitefish populations revealed by otolith strontium signatures – identification of stocked fish

    Henry Hägerstrand

    2015-11-01

    The strontium concentrations in the otolith cores of whitefish from River Tornionjoki were higher than that of the four otoliths with low core strontium from fishes caught at sea (Table 1. Supposing that this latter group represent stocked fish raised in freshwater ponds, the vast majority of River Tornionjoki whitefish is naturally reproduced fish. This is plausible because in River Tornionjoki, the major whitefish spawning river in Finland, no larger stocking have been made since 1990s (Jokikokko and Huhmarniemi 2014. In conclusion, the concentration of otolith core strontium differs in whitefish hatched in fresh-water and in whitefish hatched in river water or in brackish Baltic Sea water. This difference can be used to reveal stocked whitefish. Barium concentration may be an even better indicator in this respect than strontium, as previous results indicate (Hägerstrand et al., 2015. Stocked river spawning whitefish appear in large amount at the southern feeding grounds around the Åland Islands, as already indicated by e.g. Leskelä et al. (2009.

  18. A continuous time delay-difference type model (CTDDM) applied to stock assessment of the southern Atlantic albacore Thunnus alalunga

    Liao, Baochao; Liu, Qun; Zhang, Kui; Baset, Abdul; Memon, Aamir Mahmood; Memon, Khadim Hussain; Han, Yanan

    2016-09-01

    A continuous time delay-diff erence model (CTDDM) has been established that considers continuous time delays of biological processes. The southern Atlantic albacore ( Thunnus alalunga) stock is the one of the commercially important tuna population in the marine world. The age structured production model (ASPM) and the surplus production model (SPM) have already been used to assess the albacore stock. However, the ASPM requires detailed biological information and the SPM lacks the biological realism. In this study, we focus on applying a CTDDM to the southern Atlantic albacore ( T. alalunga) species, which provides an alternative method to assess this fishery. It is the first time that CTDDM has been provided for assessing the Atlantic albacore ( T. alalunga) fishery. CTDDM obtained the 80% confidence interval of MSY (maximum sustainable yield) of (21 510 t, 23 118t). The catch in 2011 (24 100 t) is higher than the MSY values and the relative fishing mortality ratio ( F 2011/ F MSY) is higher than 1.0. The results of CTDDM were analyzed to verify the proposed methodology and provide reference information for the sustainable management of the southern Atlantic albacore stock. The CTDDM treats the recruitment, the growth, and the mortality rates as all varying continuously over time and fills gaps between ASPM and SPM in this stock assessment.

  19. A continuous time delay-difference type model (CTDDM) applied to stock assessment of the southern Atlantic albacore Thunnus alalunga

    Liao, Baochao; Liu, Qun; Zhang, Kui; Baset, Abdul; Memon, Aamir Mahmood; Memon, Khadim Hussain; Han, Yanan

    2016-01-01

    A continuous time delay-diff erence model (CTDDM) has been established that considers continuous time delays of biological processes. The southern Atlantic albacore (Thunnus alalunga) stock is the one of the commercially important tuna population in the marine world. The age structured production model (ASPM) and the surplus production model (SPM) have already been used to assess the albacore stock. However, the ASPM requires detailed biological information and the SPM lacks the biological realism. In this study, we focus on applying a CTDDM to the southern Atlantic albacore (T. alalunga) species, which provides an alternative method to assess this fishery. It is the first time that CTDDM has been provided for assessing the Atlantic albacore (T. alalunga) fishery. CTDDM obtained the 80% confidence interval of MSY (maximum sustainable yield) of (21 510 t, 23 118t). The catch in 2011 (24 100 t) is higher than the MSY values and the relative fishing mortality ratio (F 2011/F MSY) is higher than 1.0. The results of CTDDM were analyzed to verify the proposed methodology and provide reference information for the sustainable management of the southern Atlantic albacore stock. The CTDDM treats the recruitment, the growth, and the mortality rates as all varying continuously over time and fills gaps between ASPM and SPM in this stock assessment.

  20. Changes in the fish community and water quality during seven years of stocking piscivorous fish in a shallow lake

    Skov, Christian; Perrow, M.R.; Berg, Søren;

    2002-01-01

    1. Piscivores (annual stocking of 1000 individuals ha(-1) of 0+ pike and a single stocking of 30 kg ha(-1) of large 20-30 cm perch) were stocked in seven consecutive years in a shallow eutrophic lake in Denmark. The stocking programme aimed at changing food-web structure by reducing zooplanktivor......1. Piscivores (annual stocking of 1000 individuals ha(-1) of 0+ pike and a single stocking of 30 kg ha(-1) of large 20-30 cm perch) were stocked in seven consecutive years in a shallow eutrophic lake in Denmark. The stocking programme aimed at changing food-web structure by reducing......) declined distinctly during the study period. This effect was attributed to predation by large (>50 cm) pike. Based on scale readings, we cautiously suggest that the stocking of 0+ pike boosted the adult pike population to produce an unexpected impact in later years. Conversely, no direct impact of stocked...... 0+ pike was detected on 0+ roach. 4. A major decline in the recruitment strength of 0+ roach was observed in 2000. A combination of (i) the indirect effect of large pike preying on adult roach, with negative effect on roach reproduction and (ii) the direct predation effect of 0+ pike and or 1+ and 2...

  1. Age dependent sensitivity of oil on fish larvae, used in assessment of potential oil pollution damages on fish resources

    Føyn, Lars; Serigstad, Bjørn

    1987-01-01

    Oil exploration in Norwegian waters will probably be extended further north into the Barents Sea. The Barents Sea is the nursery ground for important fish stocks spawning outside the norwegian coast, north of 62°N. Fish eggs and larvae are transported with the current systems northwards ending up as 0-group fish no longer dependent of the transportation provided by the currents. Some place between the egg/larval stage and mature fish, the fish is not longer vulnerable ...

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

    Lewis, Mark; Mallette, Christine; Murray, William

    2003-03-01

    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.

  3. 77 FR 27246 - Marine Mammal Protection Act; Stock Assessment Report

    2012-05-09

    ... estimated average human-caused Stock Nmin Rmax Fr PBR mortality and Stock status serious injury (5- year...-1849. Riedman, M.L., and J.A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and... maximum theoretical or estimated net productivity rate of the stock at a small population size (R...

  4. The influence of environment on stock assessment : an approach with surplus production models

    Fréon, Pierre

    1995-01-01

    Conventional global production models are not suitable for some stocks because fishing effort variations only explain only a small part of the total variability of annual catches. Often the residual variability originates from the influence of environmental phenomena, which affects either the abundance or the catchability of a stock from one year to the next. Therefore an additional environmental variable has been inserted into conventional models in order to improve their accuracy. These var...

  5. AFSC/REFM: Isolation by distance (IBD) Alaskan fish stock structure modeling

    National Oceanic and Atmospheric Administration, Department of Commerce — There is no established management protocol for stocks subject to isolation-by-distance (IBD) stock structure. This study examines several management strategies for...

  6. Microsatellite assessment of walrus (Odobenus rosmarus rosmarus stocks in Canada

    Aaron BA Shafer

    2013-08-01

    Full Text Available Walruses in Canada are currently subdivided into seven stocks based on summering areas; Western Jones Sound (WJS, Baffin Bay (BB, Penny Strait-Lancaster Sound (PS-LS, North Foxe Basin (N-FB, Central Foxe Basin (C-FB, Hudson Bay Davis Strait (HB-DS and Southern and Eastern Hudson Bay (SE-HB. In this study, walrus were sampled from six of the seven stocks (SE-HB samples were not available and genotyped at 10 microsatellite loci. All stocks were genetically diverse (average heterozygosity of 0.58 with no evidence of inbreeding (average FIS of 0.03. We detected significant genetic differentiation among the stocks and a pattern of genetic spatial autocorrelation that suggests a moderate effect of geographic distance on gene flow among stocks. Bayesian clustering suggested the six recognized stocks were elements of two larger genetic clusters - a northern Arctic population (containing BB, WJS, and PS-LS stocks and a central Arctic population (containing C-FB, N-FB, and HB-DS stocks. These populations are moderately differentiated (FST = 0.07, but based on evidence of contemporary movement from assignment tests, are not completely isolated. There was support for maintaining the WJS stock and a combined BB+PS-LS stock, although the latter conclusion is based on a small sample size. Similarly, there was some evidence suggesting separation of the Foxe Basin stocks from the HB-DS but not the N-FB from the C-FB stock. However, given that there are morphological and chemical differences between N-FB and C-FB stocks, there is currently insufficient evidence to support a revision of the current stock designations.

  7. Avoidance within a changing assessment paradigm for Mediterranean Hake stocks

    S. RAGONESE

    2012-12-01

    Full Text Available The Mediterranean hake Merluccius merluccius L., 1758, is the emblem of the so-called Mediterranean demersal fisheries paradox, showing a persistent, although stable, status of growth overexploitation and an impressive gap between current and any biological reference point. Almost full avoidance capability of large size females to bottom trawls, higher overall growth rates than previously believed and higher natural mortality in juveniles than adult, were considered among the most plausible explanation factors of such persistence. In the present note, arguments are illustrated to raise some concern about avoidance and highlight the important role of the other factors in improving assessments and launching a short term recovery plan for Mediterranean Hake stocks which is more acceptable to fishermen.

  8. Length-based assessment of coral reef fish populations in the main and northwestern Hawaiian islands.

    Nadon, Marc O; Ault, Jerald S; Williams, Ivor D; Smith, Steven G; DiNardo, Gerard T

    2015-01-01

    The coral reef fish community of Hawaii is composed of hundreds of species, supports a multimillion dollar fishing and tourism industry, and is of great cultural importance to the local population. However, a major stock assessment of Hawaiian coral reef fish populations has not yet been conducted. Here we used the robust indicator variable "average length in the exploited phase of the population ([Formula: see text])", estimated from size composition data from commercial fisheries trip reports and fishery-independent diver surveys, to evaluate exploitation rates for 19 Hawaiian reef fishes. By and large, the average lengths obtained from diver surveys agreed well with those from commercial data. We used the estimated exploitation rates coupled with life history parameters synthesized from the literature to parameterize a numerical population model and generate stock sustainability metrics such as spawning potential ratios (SPR). We found good agreement between predicted average lengths in an unfished population (from our population model) and those observed from diver surveys in the largely unexploited Northwestern Hawaiian Islands. Of 19 exploited reef fish species assessed in the main Hawaiian Islands, 9 had SPRs close to or below the 30% overfishing threshold. In general, longer-lived species such as surgeonfishes, the redlip parrotfish (Scarus rubroviolaceus), and the gray snapper (Aprion virescens) had the lowest SPRs, while short-lived species such as goatfishes and jacks, as well as two invasive species (Lutjanus kasmira and Cephalopholis argus), had SPRs above the 30% threshold. PMID:26267473

  9. Pike ( Esox lucius L.) stocking as a biomanipulation tool .1. Effects on the fish population in Lake Lyng, Denmark

    Berg, Søren; Jeppesen, E.; Søndergaard, M.

    1997-01-01

    From 1990-1993 juvenile pike (Esox lucius) were stocked each spring in the eutrophic Lake Lyng (9.9 ha, max. depth 7.6 m, mean depth 2.4 m) in densities between 515 and 3616 pike ha(- 1). In 1989-90 the fish population consisted mainly of roach (Rutilus rutilus), rudd (Scardinius erythrophthalmus......), perch (Perca fluviatilis) and ruffe (Gymnocephalus cernuus), and total fish biomass was estimated at 477 kg ha(-1). Prior to stocking pike was not present in the lake. Following the first year of stocking, the density of roach, rudd and ruffe fry expressed as catch per unit effort decreased...... significantly by 64 to 97%. In 1991 ruffe disappeared completely. The pike stocking did not affect the density of perch significantly. The growth of pike was high and also the growth of perch increased significantly from 1990 to 1991 (p <0.001) and from 1991 to 1994 (p <0.001). We found a linear negative...

  10. The tower of Babel: Different perceptions and controversies on change and status of North Sea fish stocks in multi-stakeholder settings

    Verweij, M.C.; Densen, van W.L.T.; Mol, A.P.J.

    2010-01-01

    Fishermen, scientists, national policy makers, and staff of environmental NGOs (ENGOs) hold different perceptions about temporal patterns in fish stocks. Perception differences are problematic in multi-stakeholder settings, because they elicit controversies and unbalanced disputes. These hinder effe

  11. 78 FR 19002 - Marine Mammal Protection Act; Draft Revised Stock Assessment Reports for Two Stocks of West...

    2013-03-28

    ... Antillean manatees (Trichechus manatus manatus) and the Florida manatee stock (Trichechus manatus... Indian manatee stocks Nmin Rmax Fr PBR human-caused Stock status mortality (5- year average)...

  12. Environmental Assessment of Sport Fishing : Meredosia National Wildlife Refuge

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment considers the biological, environmental, and socioeconomic effects of establishing a sport fishing program at Meredosia National...

  13. Environmental Assessment : Marais Des Cygnes NWR fishing plan

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is for the implemetation of a fishing program on Marais Des Cygnes National Wildlife Refuge. The Findning of No Significant Impact...

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

    Sebastián Vergara

    2007-03-01

    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.

  15. AFSC/REFM: North Pacific Groundfish Stock Assessment Chapters, 1998-present

    National Oceanic and Atmospheric Administration, Department of Commerce — Members of the Alaska Fisheries Science Center's (AFSC) Stock Assessment and Multispecies Assessments Program are responsible for determining the condition of...

  16. Active Fish Tracking Sonar (AFTS) for Assessing Fish Behavior

    Hedgepeth, J (Tenera Environmental, LLC); Johnson, Gary E.(BATTELLE (PACIFIC NW LAB)); Skalski, John R.; Burczynski, J (BioSonics Inc.)

    2002-11-01

    Active fish tracking sonars (AFTS) were used in 2001 to study fish movement in response to intake occlusion plates at The Dalles Dam on the Columbia River. AFTS provides three-dimensional fish tracks by aligning the axis of a split-beam transducer with a fish target. High-speed stepper motors move the transducer so that a tracked target remains on-axis. Occlusion plates with lateral extensions covered the top half of the turbine intakes to produce a fish friendly near-dam environment. Two AFTS were positioned at the center of Main Unit 1, one each for monitoring installed and removed plate conditions. A regression analysis showed that occlusion plates had pronounced effects on fish movement along the dam. The plates appeared to inhibit movement toward the spillway, movement toward the dam (especially in front of the turbine intake), and movement downward toward the turbines. Fish fate (as opposed to movement directions from regression slopes) into particular areas was determined using Markov-chain analysis. The sluiceway (a safer passage route above the turbine intake) zone of influence was larger with the occlusion plates installed, contrary to the regression results. In addition, the probability of passage out the near turbine and bottom sides of the sample volume was about 50% lower with occlusion plates installed.

  17. 78 FR 3399 - Draft 2012 Marine Mammal Stock Assessment Reports

    2013-01-16

    ..., 2012 (77 FR 47043); the 90-day public comment period closed on November 5, 2012. Subsequent to.... The 2011 abundance estimate for fin whale, western North Atlantic stock, in the draft 2012 SAR (77 FR... and PBR. The abundance estimate for sei whale, Nova Scotia stock, in the draft 2012 SAR (77 FR...

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

    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

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

    György Á.I.

    2012-06-01

    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.

  20. Insights into fisheries management practices: using the theory of planned behavior to explain fish stocking among a sample of Swiss anglers.

    Eike von Lindern

    Full Text Available Using inadequate management tools often threatens the natural environment. This study focuses on the example of Swiss recreational fishermen (hereafter called "anglers" as recreational fisheries management stakeholders. In recreational fisheries, fish stocking conducted by anglers has been identified as one important factor associated with declining fish catches. We therefore aimed to a gain insights into why anglers want to maintain fish stocking and b identify entry points for interventions to promote more pro-ecological management practices. Results (N = 349 showed that the majority of anglers think very uncritically about stocking and that they frequently engage in it. We conclude that outcome expectancies and beliefs about risks, in combination with a lack of stocking success controls are the main reasons that anglers retain stocking measures. We suggest that providing anglers with direct experience and feedback about stocking success is suitable to change their intentions regarding stocking and their actual stocking behavior, and thus, to promote more pro-ecological management methods. From a more general perspective, the results of this study are likely to help improve pro-ecological ecosystem management in other domains where problems similar to those in recreational fisheries management might exist.

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

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar;

    2001-01-01

    , 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...

  2. Temporal Assessment of Growing Stock, Biomass and Carbon Stock of Indian Forests

    Manhas, R.K.; Negi, J.D.S.; Chauhan, P.S. [Forest Ecology and Environment Division, Forest Research Institute, Dehradun, 248 006, Uttaranchal (India); Kumar, R. [Forest Survey of India, Dehradun, 248 001, Uttaranchal (India)

    2006-01-15

    The dynamics of terrestrial ecosystems depends on interactions between carbon, nutrient and hydrological cycles. Terrestrial ecosystems retain carbon in live biomass (aboveground and belowground), decomposing organic matter, and soil. Carbon is exchanged naturally between these systems and the atmosphere through photosynthesis, respiration, decomposition, and combustion. Human activities change carbon stock in these pools and exchanges between them and the atmosphere through land-use, land-use change, and forestry. In the present study we estimated the wood (stem) biomass, growing stock (GS) and carbon stock of Indian forests for 1984 and 1994. The forest area, wood biomass, GS, and carbon stock were 63.86 Mha, 4327.99 Mm{sup 3}, 2398.19 Mt and 1085.06 Mt respectively in 1984 and with the reduction in forest area, 63.34 Mha, in 1994, wood biomass (2395.12 Mt) and carbon stock (1083.69 Mt) also reduced subsequently. The Conifers, of temperate region, stocked maximum carbon in their woods, 28.88 to 65.21 t C/ha, followed by Mangrove forests, 28.24 t C/ha, Dipterocarp forests, 28.00 t C/ha, and Shorea robusta forests, 24.07 t C/ha. Boswellia serrata, with 0.22 Mha forest area, stocked only 3.91 t C/ha. To have an idea of rate of carbon loss the negative changes (loss of forest area) in forest area occurred during 1984-1994 (10yrs) and 1991-1994 (4yrs) were also estimated. In India, land-use changes and fuelwood requirements are the main cause of negative change. Total 24.75 Mt C was lost during 1984-1994 and 21.35 Mt C during 1991-94 at a rate of 2.48 Mt C/yr and 5.35 Mt C/yr respectively. While in other parts of India negative change is due to multiple reasons like fuelwood, extraction of non-wood forest products (NWFPs), illicit felling etc., but in the northeastern region of the country shifting cultivation is the only reason for deforestation. Decrease in forest area due to shifting cultivation accounts for 23.0% of the total deforestation in India, with an annual

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

    Neira, Sergio; Arancibia, Hugo

    2013-10-01

    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.

  4. The use of Depletion Methods to assess Mediterranean cephalopod stocks under the current EU Data Collection Framework

    S. KELLER

    2015-11-01

    Full Text Available Fuelled by the raising importance of cephalopod fisheries in Europe, there have been demands from scientists and stakeholders for their assessment and management. However, little has been done to improve the data collection in order to analyse cephalopod populations under the EU Data Collection Framework (DCF. While the DCF allows member states to design flexible national sampling programmes, it establishes the minimum data requirements (MDR each state is obliged to fulfil. In this study, it was investigated whether such MDR currently set by the DCF allow the application of depletion models (DMs to assess European cephalopod stocks. Squid and cuttlefish fisheries from the western Mediterranean were used as a case study. This exercise sheds doubt on the suitability of the MDR to properly assess and manage cephalopod stocks by means of DMs. Owing to the high plasticity of life-history traits in cephalopod populations, biological parameters should be estimated during the actual depletion period of the fished stocks, in contrast with the triennial sampling established by the DCF. In order to accurately track the depletion event, the rapid growth rates of cephalopods implies that their populations should be monitored at shorter time scales (ideally weekly or biweekly instead of quarterly as required by the DCF. These measures would not demand additional resources of the ongoing DCF, but a redistribution of sampling efforts during the depletion period. Such changes in the sampling scheme could be designed and undertaken by the member states or directly integrated as requirements.

  5. Annual stock assessment – CWT (USFWS): Annual report 2003

    US Fish and Wildlife Service, Department of the Interior — In 1989 the Bonneville Power Administration (BPA) began funding the evaluation of production groups of juvenile anadromous fish not being coded-wire tagged for...

  6. Stock assessment model outputs for ICCAT (International) managed species

    National Oceanic and Atmospheric Administration, Department of Commerce — Includes outputs from the various models run in the evaluation of stock status for species managed by the International Commission for the Conservation of Atlantic...

  7. Principles of fish welfare assessment in farm rearing conditions

    Relić Renata R.

    2010-01-01

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

  8. Assessment of Fish Biodiversity in Oni River, Ogun State, Nigeria

    Obe Bernardine Wuraola

    2011-09-01

    Full Text Available For the purpose of sustainable exploitation of the fishery resourcesof Oni River, Ogun State, Nigeria, the fish biodiversity assessment was carried out. This was conducted by enumerating and identifying fish species composition, measuring the fish length, fish weight, assessing the fish abundance and biomass, determining the length-weight relationships and the length-frequency of the fishes. Altogether, 592 fishes were sampled comprising twenty-eight (28 species belonging to sixteen (16 families. The families identified included: Cichlidae, Mormyridae, Clariidae, Channidae, Malapteruridae, Gymnarchidae, Bagridae, Mochokidae, Polypteridae, Pantodontidae,Schilbeidae, Anabantidae, Osteoglossidae, Characidae, Notopteridaeand Distichodontidae. The family Mormyridae was the most abundant with 163 members followed by Cichlidae with 161 members. The least represented family was Schilbeidae with only two (2 members. On the species level, Tilapia zillii had the greatest number of representation with seventy (70 members, followed by Oreochromis niloticus with fifty-eight (58 members.

  9. Assessment of Intellectual Capital in Joint-Stock Companies

    Rima Tamošiūnienė

    2015-12-01

    Full Text Available The evaluation of intellectual capital factors is an essential part for the management of joint-stock companies. Many authors indicate that successful intellectual capital management increases value added in joint-stock companies. Nevertheless, intellectual capital is a complex and challenging concept as there is still no clear guidance, what the intellectual capital features and its structural parts are. Theoretical research revealed that scientists accentuate various intellectual capital parts depending basically on the type of their research, on the level of the research (micro, mezzo, macro, variables they selected to investigate and similar. This research paper gives an insight what drivers can be increasing value added in joint-stock companies.

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

    Laugen, Ane T.; Engelhard, Georg H.; Whitlock, Rebecca;

    2014-01-01

    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...... 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...

  11. 78 FR 32377 - Draft 2012 Marine Mammal Stock Assessment Reports

    2013-05-30

    .... NMFS solicited public comments on the draft 2012 SARs on August 7, 2012 (77 FR 47043); the 90-day... revised draft 2012 SARs for these ten stocks (78 FR 3399, January 16, 2013). The public comment period on..., mass-stranding, etc. ] The authors mention that the most frequently found disease processes...

  12. 76 FR 52940 - Draft 2011 Marine Mammal Stock Assessment Reports

    2011-08-24

    ... false killer whale (75 FR 2853, 19 January 2010). Details on the Take Reduction Plan and its proposed implementation were published in 2011 (76 FR 42082, 18 July 2011). New information on a population viability... National Oceanic and Atmospheric Administration RIN 0648-XA595 Draft 2011 Marine Mammal Stock...

  13. 78 FR 19446 - Marine Mammal Stock Assessment Reports

    2013-04-01

    ... public review and comment for 90 days (77 FR 47043, August 7, 2012). NMFS received comments on the draft... stocks (78 FR 3399, January 16, 2013). The public comment period on the revised reports closes on April... calculate PBR (Nmin*0.5Rmax*Fr) results in a number that is not consistent with the narrative definition...

  14. 76 FR 34054 - Marine Mammal Stock Assessment Reports

    2011-06-10

    ... public review and comment (75 FR 46912, August 4, 2010). The MMPA also specifies that the comment period... stocks of harbor seals. Response: As noted in previous responses to comments (see 72 FR 12774, March 15, 2007, comment 16; 73 FR 21111, April 18, 2008, comment 23; 74 FR 19530, April 29, 2009, comment 21;...

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

    Jacobsen, Lene

    2005-01-01

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

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

    Enton Spaho

    2012-06-01

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

  17. Fish sampling with active methods

    Kubečka, Jan; Godo, O. R.; Hickley, P.; Prchalová, Marie; Říha, Milan; Rudstam, L.; Welcomme, R.

    2012-01-01

    Roč. 123, July (2012), s. 1-3. ISSN 0165-7836 Institutional support: RVO:60077344 Keywords : fish stock assessment * active and passive gear * intercalibration Subject RIV: EH - Ecology, Behaviour Impact factor: 1.695, year: 2012

  18. Towards sustainable fisheries of the Öresund cod (Gadus morhua) through sub-stock-specific assessment and management recommendations

    Lindegren, Martin; Waldo, Staffan; Nilsson, P. Anders; Svedäng, Henrik; Persson, Anders

    2013-01-01

    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......-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....

  19. Assessment of South Pacific albacore stock ( Thunnus alalunga) by improved Schaefer model

    Wang, Chien-Hsiung; Wang, Shyh-Bin

    2006-04-01

    Based on catch and effort data of tuna longline fishery operating in the South Pacific Ocean, the South Pacific albacore stock was assessed by an improved Schaefer model. The results revealed that the intrinsic growth rate was about 1.283 74 and carrying capacities vareied in the range from 73 734 to 266 732 metric tons. The growth ability of this species is remarkable. Stock dynamics mainly depends on environmental conditions. The stock is still in good condition. However, the continuous decreasing of biomass in recent years should be noticed.

  20. Hypertrophy in fishponds results in weaker top-down effect of fish stock nad less efficient fish productivity

    Potužák, J.; Hůda, J.; Pechar, Libor

    Olsztyn: European aquaculture society, 2008 - (Kamler, E.; Dabrowski, K.). s. 537-538 ISBN 978-83-60111-30-7 R&D Projects: GA MŠk(CZ) 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : Top-down Effect * plankton * fish production Subject RIV: DA - Hydrology ; Limnology

  1. 1982 Aleutian Islands salmon stock assessment study: Legislative report

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a comprehensive research study of the Aleutian Islands salmon resources in 1982. The study encompassed the area west of Unimak Pass to Attu...

  2. A Framework for Assessing Global Change Risks to Forest Carbon Stocks in the United States

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

    2013-01-01

    Among terrestrial environments, forests are not only the largest long-term sink of atmospheric carbon (C), but are also susceptible to global change themselves, with potential consequences including alterations of C cycles and potential C emission. To inform global change risk assessment of forest C across large spatial/temporal scales, this study constructed and evaluated a basic risk framework which combined the magnitude of C stocks and their associated probability of stock change in the c...

  3. African Stock Market Performance Dynamics: A Multidimensional Convergence Assessment

    Simplice A, Asongu

    2012-01-01

    This paper dissects with great acuteness, the issues of convergence in financial performance dynamics in the African continent through the lenses of stock market capitalization, value traded, turnover and number of listed companies. The empirical evidence is premised on 11 homogenous panels based on regions (sub-Saharan and North Africa), income-levels (Low, Middle, Lower-middle and Upper-middle), legal-origins (English common-law and French civil-law) and religious dominations (Christianity ...

  4. Assessment of the eel stock in Sweden, spring 2015

    Dekker, Willem

    2015-01-01

    The population of the European eel Anguilla anguilla (L.) is in severe decline. In 2007, the European Union decided on a Regulation establishing measures for the recovery of the stock, which obliged Member States to implement a national Eel Management Plan by 2009. Sweden submitted its plan in 2008. According to the Regulation, Member States will report to the Commission every third year, on the implementation of their Eel Management Plans and the progress achieved in protection and restorati...

  5. AFSC/REFM: Isolation by distance (IBD) Alaskan fish stock structure modeling (NCEI Accession 0130929)

    National Oceanic and Atmospheric Administration, Department of Commerce — This model study examines several management strategies for two marine fish species subject to isolation-by-distance (IBD): Pacific cod in the Aleutian Islands (AI)...

  6. Improving capacity of stock assessment for sea turtles: using ocean circulation modeling to inform genetic mixed stock analysis

    National Oceanic and Atmospheric Administration, Department of Commerce — Genetic approaches have been useful for assigning stock ID to sea turtles caught as bycatch in fisheries, or determining stock composition at foraging grounds. In...

  7. Data collected from underwater visual surveys of fish stocks at twenty-three sites in West Hawaii, 1999 - 2005 (NODC Accession 0002767)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data are from underwater visual surveys of fish stocks at 23 sites in West Hawaii. Survey sites are 8 to 14 m deep and are all located on reef shelfs with moderate...

  8. Defining, assessing and promoting the welfare of farmed fish.

    Huntingford, F A; Kadri, S

    2014-04-01

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

  9. SURROGATE SPECIES IN ASSESSING CONTAMINANT RISK FOR ENDANGERED FISHES

    Rainbow trout, fathead minnows, and sheepshead minnows were tested as surrogate species to assess contaminant risk for 17 endangered fishes and one toad species. Acute toxicity tests were conducted with carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin in accord...

  10. South Florida Seagrass Fish and Invertebrate Assessment Network (FIAN)

    U.S. Geological Survey, Department of the Interior — The South Florida Fish and Invertebrate Assessment Network (FIAN) is a monitoring project within the Comprehensive Everglades Restoration Plan (CERP). It is an...

  11. Suitable stocking density of tilapia in an aquaponic system

    Rahmatullah, R.; Das, M; Rahmatullah, S.M.

    2010-01-01

    An aquaponic system was studied through the integrated culture of mono-sex GIFT and two types of vegetables viz. morning glory, Ipomoea reptans and taro, Colocasia esculenta in a recirculating system for 15 weeks. Tilapia fry of uniform size of 0.76 g were released in three treatments (stocking densities): 106 fish/m³ (T1), 142 fish/m³ (T2) and 177 fish/m³ (T3) to assess the effect of stocking density on the growth performance of fish. Fish were fed with a commercial feed containing 25% prote...

  12. The relationship between stocking eggs in boreal spawning rivers and the abundance of brown trout parr

    Syrjänen, Jukka; Ruokonen, Timo; Ketola, Tarmo; Valkeajärvi, Pentti

    2015-01-01

    Stocking with eggs has been widely used as a management measure to support degraded salmonid stocks. In Finland, Atlantic salmon and both sea-migrating and lake-migrating brown trout are stocked as eggs, alevins, fry, parr, and smolt, whereas trout are also stocked as mature fish. The aim of this stocking is to improve catches and to support collapsed spawning stocks. We assessed the success of stocking with brown trout eggs in a study of 17 Finnish boreal forest rivers, of which 9 were subje...

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

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

    2008-01-01

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

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

    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)

  15. The effects of periphyton substrate and fish stocking density on water quality

    Azim, M.E.; Verdegem, M.C.J.; Singh, M.; Dam, van A.A.; Beveridge, M.C.M.

    2003-01-01

    The objectives of this study were to determine how periphyton and phytoplankton biomass vary with grazing pressure by tilapia Oreochromis niloticus, to evaluate the growth performance of fish when substrate is introduced and to calculate the efficiency of nitrogen utilization in substrate and non-su

  16. Climate change and credibility of fish stock agreements : the case of the north-east arctic cod

    Ekerhovd, Nils-Arne

    2010-01-01

    We simulate how an increase in the productivity of the North-East Arctic cod stock would affect the Russian-Norwegian cooperation on the management of the stock. The productivity increase is linked to environmental conditions in the sea and to climate change through a temperature-dependent stock-recruitment relationship, where the numbers of recruits is positively related to the sea temperature given the spawning stock biomass. Increased recruitment and productivity of the stock improved the...

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

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

  18. Mercury toxicology as assessed through fish scales.

    Dua, A; Gupta, N

    2005-06-01

    Increasing pollution in water bodies is directly or indirectly related to increasing urbanization and indiscriminate disposal of agrochemical & industrial effluents. Heavy metals are one of the important categories of such pollutants and are causing serious hazards to non target species (Mwachiro and Druve1997). Their salts constitute a serious type of pollution in fresh water and being stable compounds; they are not readily removed by oxidation, precipitation or other processes and affect the activity in recipient animal (Jagadeesan and Vijayalakshmi 1998). Increase in the concentration of heavy metals has been reported in water of Vasai Creek, Maharastra and surface as well as groundwater of Delhi (Lokhande and Kelker 1999; Dixit et al. 2003). Recently, Food and Drug Adminstration (USFDA) and Environmental Protection Agency (USEPA) (2004) in their combined report recommended that pregnant women and lactating mothers should not eat shark, sword fish and king Mackerel as these fishes contain high levels of mercury. PMID:16158848

  19. Hydroacoustic estimates of fish stocks in temperate reservoirs: day or night surveys?

    Draštík, Vladislav; Kubečka, Jan; Čech, Martin; Frouzová, Jaroslava; Říha, Milan; Jůza, Tomáš; Tušer, Michal; Jarolím, Oldřich; Prchalová, Marie; Peterka, Jiří; Vašek, Mojmír; Kratochvíl, Michal; Matěna, Josef; Mrkvička, Tomáš

    2009-01-01

    Roč. 22, č. 1 (2009), s. 69-77. ISSN 0990-7440 R&D Projects: GA ČR(CZ) GA206/06/1371; GA ČR(CZ) GA206/07/1392; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517 Keywords : hydroacoustics * fish biomass * diel migration * man-made lake Subject RIV: EH - Ecology, Behaviour Impact factor: 1.227, year: 2009

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

    Jakobsen, Tore

    1981-01-01

    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 NorthEa...

  1. A large-scale field assessment of carbon stocks in human-modified tropical forests.

    Berenguer, Erika; Ferreira, Joice; Gardner, Toby Alan; Aragão, Luiz Eduardo Oliveira Cruz; De Camargo, Plínio Barbosa; Cerri, Carlos Eduardo; Durigan, Mariana; Cosme De Oliveira Junior, Raimundo; Vieira, Ima Célia Guimarães; Barlow, Jos

    2014-12-01

    Tropical rainforests store enormous amounts of carbon, the protection of which represents a vital component of efforts to mitigate global climate change. Currently, tropical forest conservation, science, policies, and climate mitigation actions focus predominantly on reducing carbon emissions from deforestation alone. However, every year vast areas of the humid tropics are disturbed by selective logging, understory fires, and habitat fragmentation. There is an urgent need to understand the effect of such disturbances on carbon stocks, and how stocks in disturbed forests compare to those found in undisturbed primary forests as well as in regenerating secondary forests. Here, we present the results of the largest field study to date on the impacts of human disturbances on above and belowground carbon stocks in tropical forests. Live vegetation, the largest carbon pool, was extremely sensitive to disturbance: forests that experienced both selective logging and understory fires stored, on average, 40% less aboveground carbon than undisturbed forests and were structurally similar to secondary forests. Edge effects also played an important role in explaining variability in aboveground carbon stocks of disturbed forests. Results indicate a potential rapid recovery of the dead wood and litter carbon pools, while soil stocks (0-30 cm) appeared to be resistant to the effects of logging and fire. Carbon loss and subsequent emissions due to human disturbances remain largely unaccounted for in greenhouse gas inventories, but by comparing our estimates of depleted carbon stocks in disturbed forests with Brazilian government assessments of the total forest area annually disturbed in the Amazon, we show that these emissions could represent up to 40% of the carbon loss from deforestation in the region. We conclude that conservation programs aiming to ensure the long-term permanence of forest carbon stocks, such as REDD+, will remain limited in their success unless they effectively

  2. The effect of hydropower on fish stocks: comparison between cascade and non-cascade reservoirs

    Draštík, Vladislav; Kubečka, Jan; Tušer, Michal; Čech, Martin; Frouzová, Jaroslava; Jarolím, Oldřich; Prchalová, Marie

    2008-01-01

    Roč. 609, č. 1 (2008), s. 25-36. ISSN 0018-8158. [EIFAC Symposium on hydropower , flood control and water abstraction: implications for fish and fisheries. Mondsee, 14.06.2006-17.06.2006] R&D Projects: GA ČR(CZ) GA206/06/1371; GA ČR(CZ) GA206/02/0520; GA ČR(CZ) GA206/07/1392; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517 Keywords : abundance * biomass * longitudinal gradient * vertical and horizontal distribution * cascade Subject RIV: EH - Ecology, Behaviour Impact factor: 1.449, year: 2008

  3. Annual dynamics of the fish stock in a backwater of the River Dyje

    Lusk, Stanislav; Halačka, Karel; Lusková, Věra; Horák, Václav

    2001-01-01

    Roč. 17, 4-5 (2001), s. 571-581. ISSN 0886-9375. [International Symposium on Regulated Streams /8./. Toulouse, 17.07.2000-21.07.2000] R&D Projects: GA ČR GA206/99/1519; GA ČR GA206/00/0668; GA AV ČR IBS6093007; GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6093917 Keywords : backwater * fish communities * River Dyje Subject RIV: EF - Botanics Impact factor: 1.169, year: 2001

  4. Brood stock formation of the hermaphrodite finfish species Pagellus erythrinus (common Pandora from fish reared in captivity

    S.D. KLAOUDATOS

    2012-12-01

    Full Text Available Formation of brood stock is considered to be one of the most important operations in order to acquire eggs and fry from any promising candidate finfish species for aquaculture production. The sex reversal observed in hermaphrodite species adds to confusion and creates additional complications in forming a brood stock. The present study describes the efforts and the results of the brood stock formation of the hermaphrodite finfish species Pagellus erythrinus (common Pandora from individuals aged between 4 and 5 years (TL>300mm reared in floating cages. Six groups were formed (50 fish/group in all of which females were present comprising 20 to 40% of the population. The presence of females was in contrast to the literature, which reported that sex reversal of the common Pandora is complete in naturally occurring populations with the absence of females in sizes of a total length greater than 220mm, indicating that in captivity sex reversal is not complete for this species. Four of the groups formed spawned under natural environmental conditions without hormonal treatment and the other two groups were administered a different dosage (250 and 500 IU/kg of Human Chorionic Gonadotropin (HCG to induce spawning. The reproductive period started in the middle of May and ended at the beginning of July and spontaneous spawning occurred in all groups. Egg release lasted for a mean period of one month for the groups that spawned without hormonal treatment with no significant difference in the number of viable eggs between groups. The groups that spawned under hormonal treatment released eggs for a period of six and seven days, for the group that spawned under the high and low hormonal treatment, respectively, with no significant difference in the number of viable eggs between them. The hormonal induced spawning resulted in egg release within a short period of time ideal for a hatchery. However, the number of viable eggs produced was significantly lower

  5. Kootenai River Resident Fish Assessment, FY2008 KTOI Progress Report.

    Holderman, Charles

    2009-06-26

    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.

  6. California Fish Passage Assessment Database [ds69

    California Department of Resources — The Passage Assessment Database shapefile contains locations of known and potential barriers to salmonid migration in California streams with additional information...

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

    Maribel Recharte

    2008-10-01

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

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

    Luis Fernando da Silva Rodrigues-Filho

    2009-01-01

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

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

    Christopher W Woodall

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

  10. Division of Aquatic Resources (DAR), Division of Lands and Natural Resources (DLNR) of the State of Hawaii Fish Stock Surveys from 41 sites on Oahu and Island of Hawaii from 1952-2000 (NODC Accession 0002754)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data are from underwater visual surveys of fish stocks from 41 survey sites on the islands of Oahu and Hawaii, conducted by biologists and technicians of Hawaii's...

  11. Production and quality assessment of fish pickles from mola (Amblypharyngodon mola) fish

    Pervin, K.; Nayeem, M.A.; Newaz, A.W.; Kamal, M.; Yeasmine, S.; Nurullah, M.

    2010-01-01

    Fish pickles (with olive and tamarind) were prepared from mola fish (Amblypharyngodon mola) and their nutritional and food quality were assessed. The quality of the pickle prepared with olive was excellent and the pickle prepared with tamarind was found good. Moisture content of the two pickle products were 43.85% (with tamarind) and 50.89% (with olive). The protein and lipid contents of tamarind added pickle were 19.13 and 35.64% respectively; pickle with olive contained less protein (13.16%...

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

    Bastardie, Francois; Nielsen, J. Rasmus; Miethe, Tanja

    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 proportional to 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...

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

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

    2014-05-01

    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

  14. The impact of bias in length frequency data on an age structured fisheries stock assessment model

    Heery, Eliza Crenshaw

    2007-01-01

    Statistical age-structured models are widely used in fisheries stock assessment. These models have been become increasingly complex over recent decades, allowing them to incorporate a larger variety of fisheries data. These typically include information regarding annual fishery yields, indices of abundance and catch composition data, which reflect the distribution of ages in the harvested population each year. In some fisheries, age composition can be determined annually through the examin...

  15. Reef Fish Survey Techniques: Assessing the Potential for Standardizing Methodologies.

    Zachary R Caldwell

    Full Text Available Dramatic changes in populations of fishes living on coral reefs have been documented globally and, in response, the research community has initiated efforts to assess and monitor reef fish assemblages. A variety of visual census techniques are employed, however results are often incomparable due to differential methodological performance. Although comparability of data may promote improved assessment of fish populations, and thus management of often critically important nearshore fisheries, to date no standardized and agreed-upon survey method has emerged. This study describes the use of methods across the research community and identifies potential drivers of method selection. An online survey was distributed to researchers from academic, governmental, and non-governmental organizations internationally. Although many methods were identified, 89% of survey-based projects employed one of three methods-belt transect, stationary point count, and some variation of the timed swim method. The selection of survey method was independent of the research design (i.e., assessment goal and region of study, but was related to the researcher's home institution. While some researchers expressed willingness to modify their current survey protocols to more standardized protocols (76%, their willingness decreased when methodologies were tied to long-term datasets spanning five or more years. Willingness to modify current methodologies was also less common among academic researchers than resource managers. By understanding both the current application of methods and the reported motivations for method selection, we hope to focus discussions towards increasing the comparability of quantitative reef fish survey data.

  16. Reef Fish Survey Techniques: Assessing the Potential for Standardizing Methodologies

    Caldwell, Zachary R.; Zgliczynski, Brian J.; Williams, Gareth J.; Sandin, Stuart A.

    2016-01-01

    Dramatic changes in populations of fishes living on coral reefs have been documented globally and, in response, the research community has initiated efforts to assess and monitor reef fish assemblages. A variety of visual census techniques are employed, however results are often incomparable due to differential methodological performance. Although comparability of data may promote improved assessment of fish populations, and thus management of often critically important nearshore fisheries, to date no standardized and agreed-upon survey method has emerged. This study describes the use of methods across the research community and identifies potential drivers of method selection. An online survey was distributed to researchers from academic, governmental, and non-governmental organizations internationally. Although many methods were identified, 89% of survey-based projects employed one of three methods–belt transect, stationary point count, and some variation of the timed swim method. The selection of survey method was independent of the research design (i.e., assessment goal) and region of study, but was related to the researcher’s home institution. While some researchers expressed willingness to modify their current survey protocols to more standardized protocols (76%), their willingness decreased when methodologies were tied to long-term datasets spanning five or more years. Willingness to modify current methodologies was also less common among academic researchers than resource managers. By understanding both the current application of methods and the reported motivations for method selection, we hope to focus discussions towards increasing the comparability of quantitative reef fish survey data. PMID:27111085

  17. Developing Cost-Effective Field Assessments of Carbon Stocks in Human-Modified Tropical Forests.

    Erika Berenguer

    Full Text Available Across the tropics, there is a growing financial investment in activities that aim to reduce emissions from deforestation and forest degradation, such as REDD+. However, most tropical countries lack on-the-ground capacity to conduct reliable and replicable assessments of forest carbon stocks, undermining their ability to secure long-term carbon finance for forest conservation programs. Clear guidance on how to reduce the monetary and time costs of field assessments of forest carbon can help tropical countries to overcome this capacity gap. Here we provide such guidance for cost-effective one-off field assessments of forest carbon stocks. We sampled a total of eight components from four different carbon pools (i.e. aboveground, dead wood, litter and soil in 224 study plots distributed across two regions of eastern Amazon. For each component we estimated survey costs, contribution to total forest carbon stocks and sensitivity to disturbance. Sampling costs varied thirty-one-fold between the most expensive component, soil, and the least, leaf litter. Large live stems (≥10 cm DBH, which represented only 15% of the overall sampling costs, was by far the most important component to be assessed, as it stores the largest amount of carbon and is highly sensitive to disturbance. If large stems are not taxonomically identified, costs can be reduced by a further 51%, while incurring an error in aboveground carbon estimates of only 5% in primary forests, but 31% in secondary forests. For rapid assessments, necessary to help prioritize locations for carbon- conservation activities, sampling of stems ≥20cm DBH without taxonomic identification can predict with confidence (R2 = 0.85 whether an area is relatively carbon-rich or carbon-poor-an approach that is 74% cheaper than sampling and identifying all the stems ≥10cm DBH. We use these results to evaluate the reliability of forest carbon stock estimates provided by the IPCC and FAO when applied to human

  18. Developing Cost-Effective Field Assessments of Carbon Stocks in Human-Modified Tropical Forests.

    Berenguer, Erika; Gardner, Toby A; Ferreira, Joice; Aragão, Luiz E O C; Camargo, Plínio B; Cerri, Carlos E; Durigan, Mariana; Oliveira Junior, Raimundo C; Vieira, Ima C G; Barlow, Jos

    2015-01-01

    Across the tropics, there is a growing financial investment in activities that aim to reduce emissions from deforestation and forest degradation, such as REDD+. However, most tropical countries lack on-the-ground capacity to conduct reliable and replicable assessments of forest carbon stocks, undermining their ability to secure long-term carbon finance for forest conservation programs. Clear guidance on how to reduce the monetary and time costs of field assessments of forest carbon can help tropical countries to overcome this capacity gap. Here we provide such guidance for cost-effective one-off field assessments of forest carbon stocks. We sampled a total of eight components from four different carbon pools (i.e. aboveground, dead wood, litter and soil) in 224 study plots distributed across two regions of eastern Amazon. For each component we estimated survey costs, contribution to total forest carbon stocks and sensitivity to disturbance. Sampling costs varied thirty-one-fold between the most expensive component, soil, and the least, leaf litter. Large live stems (≥10 cm DBH), which represented only 15% of the overall sampling costs, was by far the most important component to be assessed, as it stores the largest amount of carbon and is highly sensitive to disturbance. If large stems are not taxonomically identified, costs can be reduced by a further 51%, while incurring an error in aboveground carbon estimates of only 5% in primary forests, but 31% in secondary forests. For rapid assessments, necessary to help prioritize locations for carbon- conservation activities, sampling of stems ≥20cm DBH without taxonomic identification can predict with confidence (R2 = 0.85) whether an area is relatively carbon-rich or carbon-poor-an approach that is 74% cheaper than sampling and identifying all the stems ≥10cm DBH. We use these results to evaluate the reliability of forest carbon stock estimates provided by the IPCC and FAO when applied to human-modified forests

  19. Developing Cost-Effective Field Assessments of Carbon Stocks in Human-Modified Tropical Forests

    Berenguer, Erika; Gardner, Toby A.; Ferreira, Joice; Aragão, Luiz E. O. C.; Camargo, Plínio B.; Cerri, Carlos E.; Durigan, Mariana; Oliveira Junior, Raimundo C.; Vieira, Ima C. G.; Barlow, Jos

    2015-01-01

    Across the tropics, there is a growing financial investment in activities that aim to reduce emissions from deforestation and forest degradation, such as REDD+. However, most tropical countries lack on-the-ground capacity to conduct reliable and replicable assessments of forest carbon stocks, undermining their ability to secure long-term carbon finance for forest conservation programs. Clear guidance on how to reduce the monetary and time costs of field assessments of forest carbon can help tropical countries to overcome this capacity gap. Here we provide such guidance for cost-effective one-off field assessments of forest carbon stocks. We sampled a total of eight components from four different carbon pools (i.e. aboveground, dead wood, litter and soil) in 224 study plots distributed across two regions of eastern Amazon. For each component we estimated survey costs, contribution to total forest carbon stocks and sensitivity to disturbance. Sampling costs varied thirty-one-fold between the most expensive component, soil, and the least, leaf litter. Large live stems (≥10 cm DBH), which represented only 15% of the overall sampling costs, was by far the most important component to be assessed, as it stores the largest amount of carbon and is highly sensitive to disturbance. If large stems are not taxonomically identified, costs can be reduced by a further 51%, while incurring an error in aboveground carbon estimates of only 5% in primary forests, but 31% in secondary forests. For rapid assessments, necessary to help prioritize locations for carbon- conservation activities, sampling of stems ≥20cm DBH without taxonomic identification can predict with confidence (R2 = 0.85) whether an area is relatively carbon-rich or carbon-poor—an approach that is 74% cheaper than sampling and identifying all the stems ≥10cm DBH. We use these results to evaluate the reliability of forest carbon stock estimates provided by the IPCC and FAO when applied to human-modified forests

  20. Assessment of soil organic carbon stocks under future climate and land cover changes in Europe.

    Yigini, Yusuf; Panagos, Panos

    2016-07-01

    Soil organic carbon plays an important role in the carbon cycling of terrestrial ecosystems, variations in soil organic carbon stocks are very important for the ecosystem. In this study, a geostatistical model was used for predicting current and future soil organic carbon (SOC) stocks in Europe. The first phase of the study predicts current soil organic carbon content by using stepwise multiple linear regression and ordinary kriging and the second phase of the study projects the soil organic carbon to the near future (2050) by using a set of environmental predictors. We demonstrate here an approach to predict present and future soil organic carbon stocks by using climate, land cover, terrain and soil data and their projections. The covariates were selected for their role in the carbon cycle and their availability for the future model. The regression-kriging as a base model is predicting current SOC stocks in Europe by using a set of covariates and dense SOC measurements coming from LUCAS Soil Database. The base model delivers coefficients for each of the covariates to the future model. The overall model produced soil organic carbon maps which reflect the present and the future predictions (2050) based on climate and land cover projections. The data of the present climate conditions (long-term average (1950-2000)) and the future projections for 2050 were obtained from WorldClim data portal. The future climate projections are the recent climate projections mentioned in the Fifth Assessment IPCC report. These projections were extracted from the global climate models (GCMs) for four representative concentration pathways (RCPs). The results suggest an overall increase in SOC stocks by 2050 in Europe (EU26) under all climate and land cover scenarios, but the extent of the increase varies between the climate model and emissions scenarios. PMID:27082446

  1. Revisiting Psychoacoustic Methods for the Assessment of Fish Hearing.

    Bhandiwad, Ashwin A; Sisneros, Joseph A

    2016-01-01

    Behavioral methods have been critical in the study of auditory perception and discrimination in fishes. In this chapter, we review some of the common methods used in fish psychoacoustics. We discuss associative methods, such as operant, avoidance, and classical conditioning, and their use in constructing audiograms, measuring frequency selectivity, and auditory stream segregation. We also discuss the measurement of innate behavioral responses, such as the acoustic startle response (ASR), prepulse inhibition (PPI), and phonotaxis, and their use in the assessment of fish hearing to determine auditory thresholds and in the testing of mechanisms for sound source localization. For each psychoacoustic method, we provide examples of their use and discuss the parameters and situations where such methods can be best utilized. In the case of the ASR, we show how this method can be used to construct and compare audiograms between two species of larval fishes, the three-spined stickleback (Gasterosteus aculeatus) and the zebrafish (Danio rerio). We also discuss considerations for experimental design with respect to stimulus presentation and threshold criteria and how these techniques can be used in future studies to investigate auditory perception in fishes. PMID:26515314

  2. Fishing amplifies forage fish population collapses

    Essington, Timothy E.; Moriarty, Pamela E.; Froehlich, Halley E.; Hodgson, Emma E.; Koehn, Laura E.; Oken, Kiva L.; Siple, Margaret C.; Stawitz, Christine C.

    2015-01-01

    Forage fish provide substantial benefits to both humans and ocean food webs, but these benefits may be in conflict unless there are effective policies governing human activities, such as fishing. Collapses of forage fish induce widespread ecological effects on dependent predators, but attributing collapses to fishing has been difficult because of natural fluctuations of these stocks. We implicate fishing in forage fish stock collapses by showing that high fishing rates are maintained when sto...

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

    Argyle, Ray L.

    1992-01-01

    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.

  4. Fish welfare and quality assessment by conventional and innovative methods.

    Anna Concollato

    2015-01-01

    The overall aim of my research was on one side, to investigate the possibility of using rapid and nondestructive methods for the determination of fish fillets quality and their classification, on the other side, to find out the stunning/slaughtering method able to guarantee a minimal or to completely avoid stress condition at the moment immediately prior of the slaughtering process, by assessing the effects on fillets quality by conventional and innovative methods, from two ...

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

    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)

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

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

    2009-03-01

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

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

    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.

  8. Incorporating covariates into fisheries stock assessment models with application to Pacific herring.

    Deriso, Richard B; Maunder, Mark N; Pearson, Walter H

    2008-07-01

    We present a framework for evaluating the cause of fishery declines by integrating covariates into a fisheries stock assessment model. This allows the evaluation of fisheries' effects vs. natural and other human impacts. The analyses presented are based on integrating ecological science and statistics and form the basis for environmental decision-making advice. Hypothesis tests are described to rank hypotheses and determine the size of a multiple covariate model. We extend recent developments in integrated analysis and use novel methods to produce effect size estimates that are relevant to policy makers and include estimates of uncertainty. Results can be directly applied to evaluate trade-offs among alternative management decisions. The methods and results are also broadly applicable outside fisheries stock assessment. We show that multiple factors influence populations and that analysis of factors in isolation can be misleading. We illustrate the framework by applying it to Pacific herring of Prince William Sound, Alaska (USA). The Pacific herring stock that spawns in Prince William Sound is a stock that has collapsed, but there are several competing or alternative hypotheses to account for the initial collapse and subsequent lack of recovery. Factors failing the initial screening tests for statistical significance included indicators of the 1989 Exxon Valdez oil spill, coho salmon predation, sea lion predation, Pacific Decadal Oscillation, Northern Oscillation Index, and effects of containment in the herring egg-on-kelp pound fishery. The overall results indicate that the most statistically significant factors related to the lack of recovery of the herring stock involve competition or predation by juvenile hatchery pink salmon on herring juveniles. Secondary factors identified in the analysis were poor nutrition in the winter, ocean (Gulf of Alaska) temperature in the winter, the viral hemorrhagic septicemia virus, and the pathogen Ichthyophonus hoferi. The

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

    Phutchard Vicharnakorn

    2014-06-01

    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.

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

    Deceliere-Vergès C.

    2009-01-01

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

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

    C. Deceliere-Vergès

    2008-01-01

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

  12. Editorial note on reproductive biology of fishes

    A. C. TSIKLIRAS; K. I. STERGIOU; Froese, Rainer

    2013-01-01

    Fish reproductive biology (onset and duration of spawning, sex ratio, maturity stages, length and age at maturity, and fecundity) is important in fisheries research, stock assessment, and management. In this editorial note, we provide some criteria and recommendations on issues of fish reproductive biology, which may be useful in research planning, data analysis and presentation, as well as in manuscript preparation.

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

    M. W. Warren

    2012-06-01

    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%.

  14. Water Resource Inventory and Assessment (WRIA): Erwin National Fish Hatchery, Unicoi County, Tennessee

    US Fish and Wildlife Service, Department of the Interior — The Water Resource Inventory and Assessment (WRIA) for Erwin National Fish Hatchery (NFH) summarizes available and relevant information for hatchery water resources...

  15. Big Oaks National Wildlife Refuge : Environmental Action Statement, Environmental Assessment, Interim Hunting and Fishing Plan : 2004

    US Fish and Wildlife Service, Department of the Interior — This document contains the Environmental Action Statement, Environmental Assessment, and Interim Hunting and Fishing Plan for Big Oaks National Wildlife Refuge from...

  16. Probabilistic ecorisk assessment for fish, mammals, and birds at the Great Dismal Swamp National Wildlife Refuge

    US Fish and Wildlife Service, Department of the Interior — The primary objective of this study was to conduct a probabilistic ecological risk assessment for birds and evaluate risk to fish and mammals that may be exposed to...

  17. Environmental Assessment Pondicherry Division Silvio O. National Fish and Wildlife Refuge

    US Fish and Wildlife Service, Department of the Interior — In the September 2, 2003, Environmental Assessment, the U.S. Fish and Wildlife Service Service considered the environmental effects of acquiring 4,004 acres 1 in...

  18. The effect of stocking density on the transport of pink shrimp Farfantepenaeus brasiliensis (Crustacea: Decapoda, as live bait for sport fishing in Brazil

    Luciano Jensen

    2014-03-01

    Full Text Available The capture of juvenile shrimp as live bait for sport fishing has intensified, as has the trade of shrimp in different locations. The transport of shrimp to regions, other than those in which they are captured, is often poorly performed due to the lack of information regarding effective transport, resulting in high mortality of the transported animals. The aim of this study was to determine the optimum stocking density for the transport of juvenile Farfantepenaeus brasiliensis (weight: 5.53 ± 1.20 g and to evaluate the effect of the addition of hydrated lime in the transport water. Four stocking densities were tested for transport (1, 2, 3 and 4 ind L-1. Following the analysis of the results obtained in the density experiment, the addition of hydrated lime (0.15 g L-1 in the transport water was also tested. Water quality and the final survival were negatively correlated with increasing stocking density. The results of this study demonstrated that the highest density that can be used to avoid mortality is 3 ind L-1 for a maximum period of 10 h. The use of hydrated lime in the transport water attenuated the observed effects on water quality parameters.

  19. Fish habitat simulation models and integrated assessment tools

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

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

    Calcagnotto Daniela; Toledo-Filho Silvio de Almeida

    2000-01-01

    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 s...

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

    Ulrich, Clara; Boje, Jesper; Cardinale, Massimiliano; Gatti, Paul; le Bras, Quentin; Andersen, Michael; Hansen, Jakob Hemmer; Hintzen, Niels T.; Jacobsen, Jonathan B.; Jonsson, Patrik; Miller, David C.M.; Eg Nielsen, Einar; Rijnsdorp, Adriaan; Svedäng, Henrik; Wennhage, Håkan

    2012-01-01

    stock unit and is proposed to be assessed and managed as such. Pragmatic options are suggested for empirical harvest control rules accounting for the dynamic of local abundance, using a survey‐based biomass indicator. For the future, new scientific analyses should be developed to better inform the......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...

  2. Goodness of fit assessment for a fractal model of stock markets

    An assessment of the goodness of fit of a new stochastic model of stock dynamics is investigated. The model is the multifractional Brownian motion (mBm), introduced independently by Péltier and Lévy Véhel (1995) [2] and Benassi (1997) [3]. The analysis concerns the (un)conditional distributions of log-variations of the Dow Jones Industrial Average (DJIA). By comparing the performance of mBm with respect to a Garch (1,1), we argue that the former captures the distributional features as well as the pathwise empirical ones displayed by the U.S. Dow Jones index, while the Garch (1,1) works better in global terms

  3. Genetic assessment of ornamental fish species from North East India.

    Dhar, Bishal; Ghosh, Sankar Kumar

    2015-01-25

    Ornamental fishes are traded with multiple names from various parts around the world, including North East India. Most are collected from the wild, due to lack of species-specific culture or breeding, and therefore, such unmanaged collection of the wild and endemic species could lead to severe threats to biodiversity. Despite many regulatory policies, trade of threatened species, including the IUCN listed species have been largely uncontrolled, due to species identification problems arising from the utilization of multiple trade names. So, the development of species-specific DNA marker is indispensable where DNA Barcoding is proved to be helpful in species identification. Here, we investigated, through DNA Barcoding and morphological assessment, the identification of 128 ornamental fish specimens exported from NE India from different exporters. The generated sequences were subjected to similarity match in BOLD-IDS as well as BLASTN, and analysed using MEGA5.2 for species identification through Neighbour-Joining (NJ) clustering, and K2P distance based approach. The analysis revealed straightforward identification of 84 specimens into 35 species, while 44 specimens were difficult to distinguish based on CO1 barcode alone. However, these cases were resolved through morphology, NJ and distanced based method and found to be belonging to 16 species. Among the 51 identified species, 14 species represented multiple trade names; 17 species belonged to threatened category. Species-level identification through DNA Barcoding along with traditional morphotaxonomy reflects its efficacy in regulating ornamental fish trade and therefore, appeals for their conservation in nature. The use of trade names rather than the zoological name created the passage for trafficking of the threatened species and demands immediate attention for sustaining wildlife conservation. PMID:25447914

  4. Informing species conservation at multiple scales using data collected for marine mammal stock assessments.

    Alana Grech

    Full Text Available BACKGROUND: Conservation planning and the design of marine protected areas (MPAs requires spatially explicit information on the distribution of ecological features. Most species of marine mammals range over large areas and across multiple planning regions. The spatial distributions of marine mammals are difficult to predict using habitat modelling at ecological scales because of insufficient understanding of their habitat needs, however, relevant information may be available from surveys conducted to inform mandatory stock assessments. METHODOLOGY AND RESULTS: We use a 20-year time series of systematic aerial surveys of dugong (Dugong dugong abundance to create spatially-explicit models of dugong distribution and relative density at the scale of the coastal waters of northeast Australia (∼136,000 km(2. We interpolated the corrected data at the scale of 2 km * 2 km planning units using geostatistics. Planning units were classified as low, medium, high and very high dugong density on the basis of the relative density of dugongs estimated from the models and a frequency analysis. Torres Strait was identified as the most significant dugong habitat in northeast Australia and the most globally significant habitat known for any member of the Order Sirenia. The models are used by local, State and Federal agencies to inform management decisions related to the Indigenous harvest of dugongs, gill-net fisheries and Australia's National Representative System of Marine Protected Areas. CONCLUSION/SIGNIFICANCE: In this paper we demonstrate that spatially-explicit population models add value to data collected for stock assessments, provide a robust alternative to predictive habitat distribution models, and inform species conservation at multiple scales.

  5. Assessing potential health risks to fish and humans using mercury concentrations in inland fish from across western Canada and the United States

    Lepak, Jesse M; Hooten, Mevin B.; Eagles-Smith, Collin A.; Tate, Michael T.; Lutz, Michelle A.; Ackerman, Joshua T.; Willacker, James J.; Jackson, Allyson K.; Evers, David C.; Wiener, James G.; Pritz, Colleen Flanagan; Davis, Jay

    2016-01-01

    Fish represent high quality protein and nutrient sources, but Hg contamination is ubiquitous in aquatic ecosystems and can pose health risks to fish and their consumers. Potential health risks posed to fish and humans by Hg contamination in fish were assessed in western Canada and the United States. A large compilation of inland fish Hg concentrations was evaluated in terms of potential health risk to the fish themselves, health risk to predatory fish that consume Hg contaminated fish, and to humans that consume Hg contaminated fish. The probability that a fish collected from a given location would exceed a Hg concentration benchmark relevant to a health risk was calculated. These exceedance probabilities and their associated uncertainties were characterized for fish of multiple size classes at multiple health-relevant benchmarks. The approach was novel and allowed for the assessment of the potential for deleterious health effects in fish and humans associated with Hg contamination in fish across this broad study area. Exceedance probabilities were relatively common at low Hg concentration benchmarks, particularly for fish in larger size classes. Specifically, median exceedances for the largest size classes of fish evaluated at the lowest Hg concentration benchmarks were 0.73 (potential health risks to fish themselves), 0.90 (potential health risk to predatory fish that consume Hg contaminated fish), and 0.97 (potential for restricted fish consumption by humans), but diminished to essentially zero at the highest benchmarks and smallest fish size classes. Exceedances of benchmarks are likely to have deleterious health effects on fish and limit recommended amounts of fish humans consume in western Canada and the United States. Results presented here are not intended to subvert or replace local fish Hg data or consumption advice, but provide a basis for identifying areas of potential health risk and developing more focused future research and monitoring efforts.

  6. AVALIAÇÃO DA AQUISIÇÃO, ESTOCAGEM E VENDA DE PEIXES EM UM ESTABELECIMENTO DE PESCA ESPORTIVA EVALUATION OF ACQUISITION, STOCKING AND SALE OF FISH IN A SPORTIVE FISHING ENTERPRISE

    Eduardo Gomes Sanches

    2009-07-01

    Full Text Available Analisou-se a dinâmica de movimentação de peixes (aquisição, estocagem e venda em um empreendimento de pesca esportiva do tipo “pesque e solte”. No período compreendido entre outubro de 1999 e dezembro de 2003 foram realizadas visitas mensais a um empreendimento situado na Via Castelo Branco, no Estado de São Paulo, efetuando-se o levantamento dos dados a partir das “comandas de venda” e das notas fiscais de compra de peixes. Obtiveram-se, para cada espécie citada, as quantidades (em quilos adquiridas pelo pesqueiro (entrada de peixes e pelos clientes-pescadores (saída de peixes, cujo número também se registrou. Tais dados permitiram determinar a aquisição média de peixes por pescador por mês, conhecer as épocas de maior frequência de público, as espécies preferidas para aquisição, a biomassa estocada no viveiro etc. O acompanhamento mostrou que a dinâmica de movimentação de peixes praticada leva à imobilização de capital, põe em risco a segurança sanitária do plantel e torna a propriedade uma exportadora de poluição via água de despejo. Os parâmetros para a seleção das espécies, as técnicas de manejo, bem como os estímulos oferecidos à aquisição dos exemplares pescados são insuficientes, conspirando para a perda de rentabilidade do empreendimento. O povoamento com novos exemplares deve obedecer ao ritmo de saída (pesca/venda dos peixes, evitando-se ultrapassar a capacidade de suporte do viveiro. Portanto, não se deve ter na disponibilidade de exemplares por m3 o único fator para aumentar a captura por unidade de esforço de pesca, pois isso pode levar a um aumento descontrolado da população total do viveiro.
     
    PALAVRAS-CHAVES: Aquisição, estocagem, venda, pesca esportiva, pesque-pague. The dynamics of the movement of fish was analyzed (acquisition, stock and sale in a enterprise of sporting fishing or “fee fishing”. In the period understood between October of 1999 and

  7. Impacts of the local environment on recruitment: a comparative study of North Sea and Baltic Sea fish stocks

    Pécuchet, Lauréne; Nielsen, J. Rasmus; Christensen, Asbjørn

    2015-01-01

    local environmental variability on the recruitment strength. Hence, the prerecruits’ survival variability is studied according to geographically disaggregated and potentially impacting abiotic or biotic variables. Time series (1990–2009) of nine environmental variables consistent with the spawning......While the impact of environmental forcing on recruitment variability in marine populations remains largely elusive, studies spanning large spatial areas and many stocks are able to identify patterns common to different regions and species. In this study, we investigate the effects of the...

  8. The spectre of uncertainty in management of exploited fish stocks: The illustrative case of Atlantic bluefin tuna

    Fromentin, Jean-Marc; Bonhommeau, Sylvain; Arrizabalaga, Haritz; Kell, Laurence T.

    2014-01-01

    The recent overexploitation of East Atlantic and Mediterranean bluefin tuna stock has been well documented in the media where it has become the archetype of overfishing and general mis-management. Beyond the public debate, the crisis also highlighted how the interactions between science and management can change through time according to the awareness of the public opinion. To reflect these issues, the history of Atlantic bluefin tuna overfishing is first described. Then, the major uncertaint...

  9. Genetic composition of laboratory stocks of the self-fertilizing fish Kryptolebias marmoratus: a valuable resource for experimental research.

    Tatarenkov, Andrey; Ring, Brian C; Elder, John F; Bechler, David L; Avise, John C

    2010-01-01

    The hermaphroditic Mangrove Killifish, Kryptolebias marmoratus, is the world's only vertebrate that routinely self-fertilizes. As such, highly inbred and presumably isogenic "clonal" lineages of this androdioecious species have long been maintained in several laboratories and used in a wide variety of experiments that require genetically uniform vertebrate specimens. Here we conduct a genetic inventory of essentially all laboratory stocks of the Mangrove Killifish held worldwide. At 32 microsatellite loci, these stocks proved to show extensive interline differentiation as well as some intraline variation, much of which can be attributed to post-origin de novo mutations and/or to the segregation of polymorphisms from wild progenitors. Our genetic findings also document that many of the surveyed laboratory strains are not what they have been labeled, apparently due to the rather frequent mishandling or unintended mixing of various laboratory stocks over the years. Our genetic inventory should help to clarify much of this confusion about the clonal identities and genetic relationships of laboratory lines, and thereby help to rejuvenate interest in K. marmoratus as a reliable vertebrate model for experimental research that requires or can capitalize upon "clonal" replicate specimens. PMID:20877576

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

    Nielsen, Anders; Munch-Petersen, Sten; Eigaard, Ole Ritzau; Søvik, Guldborg; Ulmestrand, Mats

    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 th...

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

    Jørgensen, Ole A; Treble, M.A.

    2014-01-01

    The paper presents the background and the input parameters from research surveys and the commercial fishery to the assessment of the Greenland halibut stock component in NAFO Subarea 0 + Div. 1A offshore + Div. 1B-1F. During 2006-2009 catches have been around 24,000 tons. Catches increased to 26...

  12. Fish Creek Federally Endangered Freshwater Mussel Impact Assessment

    US Fish and Wildlife Service, Department of the Interior — Sediment toxicity was evaluated for one site upstream and three sites downstream of a diesel fuel spill that occurred in Fish Creek (OH and IN) in September 1993...

  13. Assessing patterns of fish demographics and habitat in stream networks

    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...

  14. Microbiological Quality Assessment of Frozen Fish and Fish Processing Materials from Bangladesh.

    Sanjee, Sohana Al; Karim, Md Ekramul

    2016-01-01

    The present study aims at the microbiological analysis of export oriented frozen fishes, namely, Jew fish, Tongue Sole fish, Cuttle fish, Ribbon fish, Queen fish, and fish processing water and ice from a view of public health safety and international trade. Microbiological analysis includes the determination of total viable aerobic count by standard plate count method and enumeration of total coliforms and fecal coliforms by most probable number method. The presence of specific fish pathogens such as Salmonella spp. and Vibrio cholerae were also investigated. The TVAC of all the samples was estimated below 5 × 10(5) cfu/g whereas the total coliforms and fecal coliforms count were found below 100 MPN/g and 10 MPN/g, respectively, which meet the acceptable limit specified by International Commission of Microbiological Specification for Food. The microbiological analysis of water and ice also complies with the specifications having TVAC < 20 cfu/mL, and total coliforms and fecal coliforms count were below the limit detection of the MPN method. Specific fish pathogens such as Salmonella sp. and V. cholerae were found absent in all the samples under the investigation. From this study, it can be concluded that the investigated frozen fishes were eligible for export purpose and also safe for human consumption. PMID:27019847

  15. A New Decision-Making Method for Stock Portfolio Selection Based on Computing with Linguistic Assessment

    Chen-Tung Chen; Wei-Zhan Hung

    2009-01-01

    The purpose of stock portfolio selection is how to allocate the capital to a large number of stocks in order to bring a most profitable return for investors. In most of past literatures, experts considered the portfolio of selection problem only based on past crisp or quantitative data. However, many qualitative and quantitative factors will influence the stock portfolio selection in real investment situation. It is very important for experts or decision-makers to use their experience or know...

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

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

    2008-02-01

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

  17. Species diversity, biomass, and carbon stock assessments of a natural mangrove forest in palawan, philippines

    Philippines claims international recognition for its mangrove-rich ecosystem which play significant functions from the viewpoint of ecosystem services and climate change mitigation. In this study, we assessed the species diversity of the natural mangrove forest of Bahile, Puerto Princesa City, Palawan and evaluated its potential to sequester and store carbon. Sixteen plots with a size of 10 m * 10 m were established using quadrat sampling technique to identify, record, and measure the trees. Diversity index and allometric equations were utilized to determine species diversity, and biomass and carbon stocks. Sediment samples in undisturbed portions using a 30 cm high and 5 cm diameter corer were collected in all plots to determine near-surface sediment carbon. The diversity index (H = 0.9918) was very low having a total of five true mangrove species identified dominated by Rhizophora apiculata Bl. with an importance value index of 148.1%. Among the stands, 74% of the total biomass was attributed to the above-ground (561.2 t ha-1) while 26% was credited to the roots (196.5 t ha-1). The total carbon sequestered and stored in the above-ground and root biomass were 263.8 t C ha-1 (50%) and 92.3 t C ha-1 (17%), respectively. Sediments contained 33% (173.75 t C ha-1) of the mangrove C-stocks. Stored carbon was equivalent to 1944.5 t CO/sub 2/ ha-1. These values suggest that Bahile natural mangrove forest has a potential to sequester and store substantial amounts of atmospheric carbon, hence the need for sustainable management and protection of this important coastal ecosystem. (author)

  18. Application of a Delay-difference model for the stock assessment of southern Atlantic albacore ( Thunnus alalunga)

    Zhang, Kui; Liu, Qun; Kalhoro, Muhsan Ali

    2015-06-01

    Delay-difference models are intermediate between simple surplus-production models and complicated age-structured models. Such intermediate models are more efficient and require less data than age-structured models. In this study, a delay-difference model was applied to fit catch and catch per unit effort (CPUE) data (1975-2011) of the southern Atlantic albacore ( Thunnus alalunga) stock. The proposed delay-difference model captures annual fluctuations in predicted CPUE data better than Fox model. In a Monte Carlo simulation, white noises (CVs) were superimposed on the observed CPUE data at four levels. Relative estimate error was then calculated to compare the estimated results with the true values of parameters α and β in Ricker stock-recruitment model and the catchability coefficient q. a is more sensitive to CV than β and q. We also calculated an 80% percentile confidence interval of the maximum sustainable yield (MSY, 21756 t to 23408 t; median 22490 t) with the delay-difference model. The yield of the southern Atlantic albacore stock in 2011 was 24122 t, and the estimated ratios of catch against MSY for the past seven years were approximately 1.0. We suggest that care should be taken to protect the albacore fishery in the southern Atlantic Ocean. The proposed delay-difference model provides a good fit to the data of southern Atlantic albacore stock and may be a useful choice for the assessment of regional albacore stock.

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

    Ebewore Solomon Okeoghene

    2013-09-01

    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.

  20. Stable lead isotope ratios from distinct anthropogenic sources in fish otoliths: a potential nursery ground stock marker.

    Spencer, K; Shafer, D J; Gauldie, R W; DeCarlo, E H

    2000-11-01

    Variations measured in the lead (Pb) stable isotope ratios in otoliths of juvenile tropical reef fish Scarus perspiculatus, Abudefduf abdominalis and Dascyllus albisella reflect mixing of anthropogenic lead from the Kaneohe Bay watershed and 'background' lead characteristic of the adjacent ocean. The otoliths and water samples collected in a transect across the bay demonstrated nearly identical Pb isotopic trends. The Pb isotopic composition of the watershed has a low 206Pb/204Pb signature primarily reflecting past combustion of tetra-ethyl Pb additive in fuels. Ocean water not contaminated by this watershed signature has a different, high 206Pb/204Pb isotopic composition, similar to previously measured Asian anthropogenic aerosols and natural eolian dusts, where the anthropogenic signal dominates. Where a history of past anthropogenic Pb contamination exists, it may be possible to use the ratios of Pb stable isotopes in fish otoliths to reconstruct the nursery grounds of fish. PMID:11118937

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

    Calcagnotto Daniela

    2000-01-01

    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.

  2. AFSC/REFM: Beaufort Sea Marine Fish Survey, Beaufort Sea, Alaska, August 2008, Fisheries Interaction Team

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska Fisheries Science Center's Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted a fish survey in the...

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

    Hansen, Michael Møller; Eg Nielsen, Einar; Bekkevold, Dorte; Mensberg, Karen-Lise Dons

    2001-01-01

    . 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...

  4. A New Decision-Making Method for Stock Portfolio Selection Based on Computing with Linguistic Assessment

    Chen-Tung Chen

    2009-01-01

    Full Text Available The purpose of stock portfolio selection is how to allocate the capital to a large number of stocks in order to bring a most profitable return for investors. In most of past literatures, experts considered the portfolio of selection problem only based on past crisp or quantitative data. However, many qualitative and quantitative factors will influence the stock portfolio selection in real investment situation. It is very important for experts or decision-makers to use their experience or knowledge to predict the performance of each stock and make a stock portfolio. Because of the knowledge, experience, and background of each expert are different and vague, different types of 2-tuple linguistic variable are suitable used to express experts' opinions for the performance evaluation of each stock with respect to criteria. According to the linguistic evaluations of experts, the linguistic TOPSIS and linguistic ELECTRE methods are combined to present a new decision-making method for dealing with stock selection problems in this paper. Once the investment set has been determined, the risk preferences of investor are considered to calculate the investment ratio of each stock in the investment set. Finally, an example is implemented to demonstrate the practicability of the proposed method.

  5. 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

    Pierre Fréon

    1995-01-01

    the total variability of annual catches. Often the residual variability originates from the influence of environmental phenomena, which affect either the abundance or the catchability of a stock from one year to the next. Therefore, an additional environmental variable has been inserted into conventional models in order to improve their aeeuracy. This variable appear in simple formulae concerning either stock abundance, or the catchability coefficient, or both. The models were developed from Schaefer's linear production model, Fox's exponential model or Pella and Tomlinson generalised model. CLlMPROD is an experimental expert-system, using artificial intelligence, which provides a statistical and graphical description of the data set and helps the user to select the model corresponding to his case according to objective eriteria. The software fits the model to the data set using a non-linear regression routine, assesses the fit with parametric and non-parametric tests, and provides a graphical representation of the results. Limitations of this kind of model are considered. The models can provide a fairly good interpretación of fishery history, particularly when a stock collapses unexpectedly without any appreciable increase in the nominal fishing effort. These models can also pro vide a useful tool efficient management of a fishery in those instances where climatic phenomena can be forecast, or when their influence is restricted to the year(s preceding exploitation. Finally, the analysis of two fisheries collapsed by a combination of overfishing and environmental changes is presented: the Senegalese sardine fishery and the south-east Pacific anchovy fishery

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

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

    2014-05-01

    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

  7. Careful risk assessment needed to evaluate transgenic fish

    Alison L Van Eenennaam; Olin, Paul G.

    2006-01-01

    The reproductive biology of fish makes them particularly amenable to genetic manipulation. A genetically engineered or “transgenic” Atlantic salmon is currently undergoing federal regulatory review, and international research is being conducted on many other species. The innate ability of fish to escape confinement and potentially invade native ecosystems elevates the ecological concerns associated with their genetic modification. Escaped transgenic fish will not invariably result in deleteri...

  8. A test for the relative strength of maternal and stock effects in spring Chinook salmon (Oncorhynchus tshawytscha) from two different hatcheries (Study site: Warm Springs Hatchery; Stocks: Warm Springs Hatchery and Carson Hatchery; Year class: 1993): Chapter 10

    Wetzel, Lisa A.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Stenberg, Karl D.

    2012-01-01

    An experiment was undertaken to determine the relative strength of maternal and stock effects in Chinook salmon (Oncorhynchus tshawytscha) reared in a common environment, as a companion study to our investigation of hatchery and wild Chinook salmon. Pure-strain and reciprocal crosses were made between two hatchery stocks (Carson and Warm Springs National Fish Hatcheries). The offspring were reared together in one of the hatcheries to the smolt stage, and then were transferred to a seawater rearing facility (USGS-Marrowstone Field Station). Differences in survival, growth and disease prevalence were assessed. Fish with Carson parentage grew to greater size at the hatchery and in seawater than the pure-strain Warm Springs fish, but showed higher mortality at introduction to seawater. The analyses of maternal and stock effects were inconclusive, but the theoretical responses to different combinations of maternal and stock effects may be useful in interpreting stock comparison studies.

  9. Exposure assessment for trace elements from consumption of marine fish 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

    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.

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

    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

  11. Replacing fish meal by food waste to produce lower trophic level fish containing acceptable levels of polycyclic aromatic hydrocarbons: Health risk assessments.

    Cheng, Zhang; Mo, Wing-Yin; Lam, Cheung-Lung; Choi, Wai-Ming; Wong, Ming-Hung

    2015-08-01

    This study aimed at using different types of food wastes (mainly containing cereal [food waste A] and meat meal [food waste B]) as major sources of protein to replace the fish meal used in fish feeds to produce quality fish. The traditional fish farming model used to culture low trophic level fish included: bighead, (Hypophthalmichthys nobilis), grass carp, (Ctenopharyngodon idellus), and mud carp, (Cirrhinus molitorella) of omnivorous chain. The results indicated that grass carp and bighead carp fed with food waste feeds were relatively free of PAHs. The results of health risk assessment showed that the fish fed with food waste feeds were safe for consumption from the PAHs perspective. PMID:25880597

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

    NONE

    1996-12-01

    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.

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

    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

  14. Assessing Sustainable Retrofit of the old Dwellings Stock in Brussels Capital Region

    TRACHTE, Sophie; EVRARD, Arnaud; Galan, Arancha; ATHANASSIADIS, Aristide; PLEA2014 - SUSTAINABLE HABITAT FOR DEVELOPING SOCIETIES

    2014-01-01

    In the framework of the research project “B³RetroTool”, a typology of existing dwellings, built before 1945, has been made, based on a literature review of main steps of the urban and building development of Brussels area. This old part of the Brussels dwellings stock has been chosen because it represents 60% of the dwelling stock but moreover, it gives to Brussels its identity, its architectural and its historical legacy. This contribution presents the methodology to identify typology, to st...

  15. Molecular assessment of commercial and laboratory stocks of Eisenia spp. (Oligochaeta: Lumbricidae) from South Africa

    Voua Otomo, Laetitia; Voua Otomo, Patricks; Bezuidenhout, Carlos C.; Maboeta, Mark S.

    2013-01-01

    DNA barcoding was used to investigate laboratory and commercial stocks of Eisenia species from four provinces of South Africa. The COI gene was partially amplified and sequenced in selected earthworms from eight local populations (focal groups) and two European laboratory stocks (non-focal groups). Only nine COI haplotypes were identified from the 224 sequences generated. One of these haplotypes was found to belong to the megascolecid Perionyx excavatus. The remaining eight haplotypes belonge...

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

    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)

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

    Rašković Božidar S.

    2011-01-01

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

  18. Fishing

    姜群山

    2002-01-01

    @@ Last Saturday my cousin (表兄) came to my home. We were very happy to see each other. We decided that the next day we went to fish. We got up very early that day. When we left home,the moon could still be seen in the sky.

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

    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)

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

    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.

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

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

    2013-01-01

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

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

    Jan A. Venter

    2012-01-01

    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.

  3. St. John, USVI Fish Assessment and Monitoring Data (2002 - Present)

    National Oceanic and Atmospheric Administration, Department of Commerce — This fish and benthic composition database is the result of a multifaceted effort described below.The intent of this work is five fold: 1) To spatially characterize...

  4. St. Croix, USVI Fish Assessment and Monitoring Data (2002 - Present)

    National Oceanic and Atmospheric Administration, Department of Commerce — This fish and benthic composition database is the result of a multifaceted effort described below. The intent of this work is five fold: 1) To spatially...

  5. Baseline assessment of fish communities of the Flower Garden Banks

    National Oceanic and Atmospheric Administration, Department of Commerce — The work developed baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys employed diving,...

  6. Distribution of otoliths in surficial sediments of the U.S. Atlantic Continental Shelf and slope and potential for reconstructing Holocene fish stocks

    Elder, Kathryn L.; Jones, Glenn A.; Bolz, George

    1996-06-01

    We examined more than 1100 surface sediment samples from the Atlantic continental margin of the United States to determine the feasibility of using fossil fish otoliths as diagnostic tools in reconstructing paleoenvironments and latitudinal distribution of fish stocks during the Holocene. Although 63% of the 1107 samples collected were from shelf areas (<140 m), the total number of shelf-derived otoliths represents only 0.3% of the entire sampled assemblage. The majority of otoliths occurred on the continental slope (400-2000 m), with a maximum concentration in sediments at 500 to 600-m water depth. Otoliths of the most commonly occurring species, Ceratoscopelus maderensis, exhibit a marked distributional boundary just south of Cape Hatteras, North Carolina (33°N), which mimics the distribution of their living counterparts. North of this boundary, C. maderensis constitutes greater than 70% of the preserved otolith assemblage, whereas more southerly regions contain no otoliths of this species. Although C. maderensis typically migrates diurnally over a depth of 300-600 m, otoliths taken from live-captured C. maderensis exhibit Δ14C values comparable to that of the dissolved inorganic carbon (DIC) of surface seawater in the study area. Accelerator mass spectrometry radiocarbon analyses of cooccurring otoliths and planktonic foraminifera from a sediment core collected south of Martha's Vineyard (40°15'N 70°51'W, 265 m) demonstrate temporal concordance throughout the Holocene. Otoliths appear to be viable, underutilized paleoceanographic tools. Specimens are found in sufficient abundance to permit temporal reconstructions of the distribution of C. maderensis and potentially several other icthyospecies along the U.S. Atlantic continental margin.

  7. An assessment of burst strength distribution data for monitoring quality of condom stocks in developing countries.

    Free, M J; Hutchings, J; Lubis, F; Natakusumah, R

    1986-03-01

    Laboratory tests were conducted on condoms to examine the changes that occur over time in indicators of condom burst strength, and to determine the relationship between laboratory-assessed condom burst strength and breakage during use in a developing country setting. Three groups of unaged condoms purchased directly from the manufacturer were used: one group exposed to UV light for 10 hours; one group exposed for five hours; and one group unexposed. A sample of each of these groups was tested according to ISO condom air burst test protocols. The remaining condoms were individually packaged in coded polyethylene bags for shipment to the developing country study site. Also used in the study was a group of condoms that had been aged for over 40 months under field conditions in a tropical climate; a sample from this group was tested by the ISO air burst test protocol and the remainder distributed to the study site. One-hundred-thirty Indonesian urban males participated in the double-blind study. Volunteers were not relying on the condom for contraceptive purposes. Each volunteer was given one individually packaged untreated condom, one condom from each treatment group, and four condoms aged in the field. Study participants were instructed to return all used condoms. Each condom that was returned after use was examined for breakage, and the unbroken condoms were subjected to an air inflation test to determine volume and pressure at burst. A comparison of the air burst volume data for a sample of unused and used condoms from the same treatment group indicates that most of the condoms that broke during use had air burst volumes below 11 liters. Therefore, a significant downward shift in the burst strength distribution as measured in the laboratory is likely to result in an increased breakage rate during use. A Condom Deterioration Index calculated from regular periodic testing of stored condom stocks is a convenient and sensitive means of monitoring trends in the

  8. A new technique for assessing fish passage survival at hydro power stations

    The HI-Z Turb'N Tag recovery method is presented as a new technique that has been successfully used at ten hydropower stations to determine turbine or spillway passage survival of fish. According to this technique, fish are tagged with the Turb'N Tag, which is pear-shaped, made of inflatable latex, and ca 35 mm long and 13 mm wide. The tag is designed to inflate after passage through the turbine, where it then floats the fish to the surface where it can be easily spotted and netted. One tag is sufficient to retrieve fish less than 18 cm long, while three tags may be needed for fish longer than 30 cm. In tests, fish were recovered in under 10 minutes from the tailrace after being tagged and released into a turbine. The tag allowed over 90% recovery of fish in most tests. The technique had minimal effect on the well-being of both hardy and sensitive species and provided an opportunity to examine recovered fish for injuries and retain them up to 72 h to assess possible delayed effects. The technique overcomes most of the logistical problems associated with conventional methods (netting, radio telemetry, mass mark-recapture) to determine turbine passage survival. The technique can also be used to assess effects of spill and fish bypass structures. 9 refs., 2 figs., 1 tab

  9. Report on the 2001 stock assessment of the River Darwen catchment

    Wilson, D.

    2002-01-01

    The River Darwen is a highly impacted Lancashire river with very little known about its fishery interest above the impassable weir at Salmesbury Bottoms. Below the weir there are populations of coarse fish around the confluence with the River Ribble. To the knowledge of local bailiff staff, prior to 1996 the fish population in the middle and upper River Darwen had never been surveyed by electric fishing. In order to address this lack of knowledge, a survey was undertaken during the summer...

  10. Establishment of Chydorus sphaericus (O.F. Muller, 1785 (Crustacea: Cladocera in Australia: consequences of mass fish stocking from Northern Europe?

    Pranay Sharma

    2014-09-01

    Full Text Available There are 11 species of genus Chydorus Leach, 1816 (Cladocera: Chydoridae in Australia, including populations of Chydorus sphaericus (O.F. Müller, 1785 morphologically undistinguishable from European ones. Our genetic study of C. sphaericus from two large artificial water bodies in the Adelaide region of South Australia led us to conclude the taxon was introduced to Australia from Europe by human activity, at least in the two studied water bodies. To provide a comprehensive sister-taxa coverage and survey of intraspecific variation, our data were complemented by sequences on Chydorus sphaericus-group from GenBank and Barcode of Life Data Systems website. We speculate that it was related to a mass stocking of introduced species of fishes from Europe. To confirm whether C. sphaericus is an invasive species due to human-mediated introductions, or whether it is a native Australian taxon, further extensive molecular studies (involving nuclear genes and detailed morphological comparisons are needed. This is a first report on the invasion of a non-daphniid species of Cladocera to Australia. Its significance for Australian ecosystems needs special future studies.