Fish Population Dynamics And Stock Assessment

This book explores how we can solve the urgent problem of optimizing the use of variable, uncertain but finite fisheries resources while maintaining sustainability from a marine-ecosystem conservation perspective. It offers readers a broad understanding of the current methods and theory for sustainable exploitation of fisheries resources, and introduces recent findings and technological developments. The book is divided into three parts: Part I discusses fish stock dynamics, and illustrates how ecological processes affecting life cycles and biological interactions in marine environments lead to fish stock variability in space and time in major fish groups; small pelagic fish, demersal fish and large predatory fish. These insights shed light on the mechanisms underlying the variability in fish stocks and form the essential biological basis for fisheries management. Part II addresses the technologies and systems that monitor changes in fisheries resources and marine ecosystems using two approaches: fishery-dependent and fishery-independent data. It also describes acoustic surveys and biological sampling, as well as stock assessment methods. Part III examines management models for effectively assessing the natural variability in fisheries resources. The authors explore ways of determining the allowable catch in response to changes in stock abundance and how to incorporate ecological processes and monitoring procedures into management models. This book offers readers a broad understanding of sustainable exploitation as well as insights into fisheries management for the next generation.

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 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.

This new edition provides updated information on population dynamics of major food fishes, and reviews the various methods used to study quantitative impacts of fishing on fish stocks. Contributors provide an historical background of the subject, then go on to cover current theories and methods of stock assessment, how these theories and methods have been applied in practice, and the effects of fisheries management on fish populations. They discuss length-based methods of stock assessment, multi-species fisheries, and provide data on fish populations in the North Atlantic, the Irish Sea, off Australia, Southeast Asia, and other regions. Completely revised and updated, including several new chapters.

The fields of fish population dynamics and stock assessment have seen major advances in the 1980s and 1990s, creating the need for a new synthesis. This text attempts that synthesis by presenting a contemporary approach for quantitative fisheries science that incorporates modern statistical and mathematical techniques. It emphasizes the link between biology and theory by explaining the assumptions inherent in the quantitative methods and models. The book covers key topics that are often overlooked in other texts, such as optimal harvesting, migratory stocks, and complex age and size-structured models. Quantitative Fish Dynamics is an ideal textbook for graduate and undergraduate courses in fish population dynamics and stock assessment. It is an indispensable reference work for fisheries scientists and others interested in conservation biology, fish and wildlife management, population ecology, and statistical applications.

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.