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Author: J. A. Gulland
Publisher: Food & Agriculture Org.
ISBN: 9789251031216
Category : Technology & Engineering
Languages : en
Pages : 112
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Book Description
This document reviews the several fish stock assessment methods based on length-frequency analysis. Emphasis is placed on sampling and collection of length-frequency data, to the estimation of population parameters such as growth, mortality and recruitment and the estimation of catch selectivity. Attention is given to the conversion of length to age using age-length keys, slicing length-frequency composition, and using modes. It reviews long-and short-term effects of changes in selection and fishing mortality, and discusses methods for long-term assessments and for short-term projections. The manual gives several examples of the most common methods used and stresses the advantages of using personal computers and the most recent software for data processing and analysis.
Author: J. A. Gulland
Publisher: Food & Agriculture Org.
ISBN: 9789251031216
Category : Technology & Engineering
Languages : en
Pages : 112
Get Book
Book Description
This document reviews the several fish stock assessment methods based on length-frequency analysis. Emphasis is placed on sampling and collection of length-frequency data, to the estimation of population parameters such as growth, mortality and recruitment and the estimation of catch selectivity. Attention is given to the conversion of length to age using age-length keys, slicing length-frequency composition, and using modes. It reviews long-and short-term effects of changes in selection and fishing mortality, and discusses methods for long-term assessments and for short-term projections. The manual gives several examples of the most common methods used and stresses the advantages of using personal computers and the most recent software for data processing and analysis.
Author: Committee on Fish Stock Assessment Methods
Publisher: National Academies Press
ISBN: 0309524326
Category : Technology & Engineering
Languages : en
Pages : 194
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Book Description
Ocean harvests have plateaued worldwide and many important commercial stocks have been depleted. This has caused great concern among scientists, fishery managers, the fishing community, and the public. This book evaluates the major models used for estimating the size and structure of marine fish populations (stock assessments) and changes in populations over time. It demonstrates how problems that may occur in fisheries data--for example underreporting or changes in the likelihood that fish can be caught with a given type of gear--can seriously degrade the quality of stock assessments. The volume makes recommendations for means to improve stock assessments and their use in fishery management.
Author: Daniel Pauly
Publisher: WorldFish
ISBN: 9711022281
Category : Fisheries
Languages : en
Pages : 463
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Book Description
Specific aims of the conference were: to identify the specific features of sampling schemes used to obtain length-frequency data for stock assessment; to review length-based methodologies for stock assessment of fish and aquatic invertebrates, with particular reference to their precision and accuracy; to review and test computer programs implementing length-based methods.
Author: J. A. Gulland
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 248
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Book Description
Describes the scientific techniques used in assessing fish stocks, evaluating the effect of fishing on these stocks, and the probable impact of different policies for developing and managing fisheries. Covers the techniques developed starting with simple models and continuing to more complex methods.
Author: Daniel D. Hoggarth
Publisher: Food & Agriculture Org.
ISBN: 9789251055038
Category : Business & Economics
Languages : en
Pages : 284
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Book Description
This publication contains guidelines for fish stock assessment and fishery management using the software tools and other outputs developed by the UK Department for International Development's Fisheries Management Science Programme (FMSP) from 1992 to 2004. It includes a CD-ROM with the installation files for each of the four FMSP software tools: LFDA (Length Frequency Data Analysis), CEDA (Catch Effort Data Analysis), YIELD and ParFish (Participatory Fisheries Stock Assessment).
Author: Committee to Review Northeast Fishery Stock Assessments
Publisher: National Academies Press
ISBN: 0309591651
Category : Technology & Engineering
Languages : en
Pages : 137
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Book Description
The collapse of cod, flounder, and haddock fish stocks in the Northeast United States has caused widespread concern among managers and fishers in the United States and Canada. The diminishing stocks have forced managers to take strict regulatory measures. Numerous questions have been raised about the adequacy of stock assessment science used to evaluate the status of these stocks and the appropriateness of the management measures taken. Based on these concerns, Congress mandated that a scientific review of the methodology and data used to evaluate these stocks be conducted. In this volume, the committee concludes that although there are improvements to be made in data collection, modeling uncertainty, and communicating between fishers, managers, and scientists, the scientific methods used in the Northeast stock assessments are sound. Recommendations are made on how the stock assessment process can be improved.
Author: Per Sparre
Publisher: Bernan Press(PA)
ISBN:
Category : Fish populations
Languages : en
Pages : 232
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Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309174406
Category : Technology & Engineering
Languages : en
Pages : 194
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Book Description
Ocean harvests have plateaued worldwide and many important commercial stocks have been depleted. This has caused great concern among scientists, fishery managers, the fishing community, and the public. This book evaluates the major models used for estimating the size and structure of marine fish populations (stock assessments) and changes in populations over time. It demonstrates how problems that may occur in fisheries dataâ€"for example underreporting or changes in the likelihood that fish can be caught with a given type of gearâ€"can seriously degrade the quality of stock assessments. The volume makes recommendations for means to improve stock assessments and their use in fishery management.
Author: Per Sparre
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 108
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Book Description
In Part 1, Manual, a selection of methods on fish stock assessment is described in detail, with examples of calculations. Special emphasis is placed on methods based on the analysis of length-frequencies. After a short introduction to statistics, it covers the estimation of growth parameters and mortality rates, virtual population methods, including age-based and length-based cohort analysis, gear selectivity, sampling, prediction models, including Beverton and Holt's yield per recruit model and Thompson and Bell's model, surplus production models, multispecies and multifleet problems, the assessment of migratory stocks, a discussion on stock/recruitment relationships and demersal trawl surveys, including the swept-area method. The manual is completed with a review of stock assessment, where an indication is given of methods to be applied at different levels of availability of input data, a review of relevant computer programs produced by or in cooperation with FAO, and a list of references, including material for further reading. In Part 2, Exercises, a number of exercises is given with solutions. The exercises are directly related to the various chapters and sections of the manual.
Author: R. Hilborn
Publisher: Springer Science & Business Media
ISBN: 1461535980
Category : Science
Languages : en
Pages : 575
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Book Description
This book really began in 1980 with our first microcomputer, an Apple II +. The great value of the Apple II + was that we could take the computer programs we had been building on mainframe and mini-computers, and make them available to the many fisheries biologists who also had Apple II + 's. About 6 months after we got our first Apple, John Glaister came through Vancouver and saw what we were doing and realized that his agency (New South Wales State Fisheries) had the same equipment and could run the same programs. John organized a training course in Australia where we showed about 25 Australian fisheries biologists how to use microcomputers to do many standard fisheries analyses. In the process of organizing this and sub sequent courses we developed a series of lecture notes. Over the last 10 years these notes have evolved into the chapters of this book.
