Fish Stock Assessment

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.

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.

Stock Assessment: Quantitative Methods and Applications for Small Scale Fisheries is a book about stock assessment as it is practiced. It focuses on applications for small scale or artisanal fisheries in developing countries, however it is not limited in applicability to tropical waters and should also be considered a resource for students of temperate fishery management problems. It incorporates a careful sample design, various mathematical models as a basis for predicting consequences for stock exploitation, and discusses the impact of exploitation on non-targeted species. This was a unique concept involving a collaborative effort between U.S. and host country scientists to address issues of regional and global concern through innovative research. Unlike other books on stock assessment that show mathematical models, this is the only book of its kind that discusses how an assessment is carried out. It looks at the field as a whole and includes sampling, age determination and acoustics. The book represents the culmination of a nine-year program financed by the United States Agency for International Development to provide new or improved methods of stock assessment for artisanal fisheries.

Fisheries tend to collapse because of fleet over-capacity, leading to harvesting the stocks of fish beyond their ability to recover. On the other hand, fish stocks may also be under-utilized because of fleet under-capacity. The fishery managers have to strike a balance by directly controlling the fishing capacity (input control) and/or by setting restrictions on the catch (output control). The key factor in the success of striking this balance is the application of fisheries management based on scientific advice coming from results of stock assessment models. This book entitled "Fish Population Dynamics and Stock Assessment" has been written to meet the requirements of graduate, post graduate students, researchers and scientists in fish stock assessment. Written in a textbook form, this book encompasses the knowledge of principles of stock assessment, sampling techniques, age determination, growth parameters, mortality parameters, gear selection, stock assessment models, fisheries management etc. If this book could help and guide the students and researchers, we shall feel amply rewarded. The book contains 16 chapters that have been explained very clearly with numerous illustrative examples, leaving no scope for confusion.

This manual examines mathematical models applied in fish stock assessment, including models and variation rates; cohort models and analyses; stock fishing patterns, components, stock-recruitment relations, short- and long-term stock projections; fisheries resources management with regards to biological reference points and regulation measures; production models; estimation of parameters; and exercises.

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).

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.

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.