Download or read book Analysis and Comparison of Age structured Assessment Models for Two Pacific Herring Populations written by Peter-John F. Hulson and published by . This book was released on 2007 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Substantial research has been devoted to identify causes for decline the of Prince William Sound (PWS) Pacific herring in the early 1990's because of the proximity to the 1989 Exxon Valdez oil spill (EVOS). A potential source for decline has been identified with the isolation of disease in the PWS population. There have been limited investigations of PWS Pacific herring population dynamics related to other stocks in the Gulf of Alaska. The objective of this thesis was to compare observations and age-structured assessment (ASA) model results between PWS and Sitka Sound Pacific herring. Data conflicts were evaluated in the PWS ASA model and indicate that hypotheses about natural mortality in the four years subsequent to EVOS depend on the type and weighting of population indices. In Sitka, the ASA model was used to show that time-dependent natural mortality can be estimated. Comparison between PWS and Sitka indicated that age structure and recruitment have been comparable, but abundance indices and weight-at-age data have not been similar after 1993. The differences identified in this thesis between PWS and Sitka imply uniqueness in natural mortality and condition within each Pacific herring population"--Leaf iii.

Download or read book Interrelationships of Pacific Herring Clupea Pallasi Populations and Their Relation to Large scale Environmental and Oceanographic Variables written by Erik Hamilton Williams and published by . This book was released on 1999 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recruitment estimates for Pacific herring, Clupea pallasi, populations in the Bering Sea and Northeast Pacific Ocean are highly variable, difficult to forecast, and crucial for determining optimum harvest levels. Age-structured population models for annual stock assessments of the sac-roe fisheries rely on fishery and survey age composition data tuned to an auxiliary survey of total biomass. In Chapter 1, the first age-structured model for Norton Sound herring was developed similarly to existing models. Estimates of variability from age-structured stock assessment models for Pacific herring are often not calculated. In Chapter 2, a parametric bootstrap procedure using a fit of the Dirichlet distribution to observed age composition data was developed as a quick and easy method for computing error estimates of model estimates. This bootstrap technique was able to capture variability beyond that of the multinomial distribution. This technique can provide estimates of variability for existing population models with age composition data requiring little change to the original model structure. Recruitment time series from Pacific herring stock assessment models for 14 populations in the Bering Sea and Northeast Pacific Ocean were analyzed for links to the environment. For some populations, recruitment series were extended backward in time using cohort analysis. In chapter 3, correlation and multivariate cluster analyses were applied to determine herring population associations. There appear to be four major herring groups: Bering Sea, outer Gulf of Alaska, coastal Southeast Alaska, and British Columbia. These associations were combined with an exploratory correlation analysis of environmental data in chapter 4. Appropriate time periods for environmental variables were determined for use in Ricker type environmentally dependent spawner-recruit forecasting models. Global and local scale environmental variables were examined in forecasting models, resulting in improvements in recruitment forecasts compared to models without environmental data. The exploratory correlation analysis and best fit models, determined by jacknife error prediction, indicated temperature data corresponding to the year of spawning resulted in the best forecasting models. The Norton Sound age-structured model, parametric bootstrap procedure, and recruitment forecasting models serve as enhancements to the decision process of managing Pacific herring fisheries.

Download or read book A Review and Comparison of Age structured Stock Assessment Models from Theoretical and Applied Points of View written by Bernard A. Megrey and published by . This book was released on 1988 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving Fish Stock Assessments written by National Research Council and published by National Academies Press. This book was released on 1998-02-27 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Quantitative Fisheries Stock Assessment written by R. Hilborn and published by Springer Science & Business Media. This book was released on 2013-12-01 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Stock Identification Methods written by Steven X. Cadrin and published by Academic Press. This book was released on 2013-10-04 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stock Identification Methods, 2e, continues to provide a comprehensive review of the various disciplines used to study the population structure of fishery resources. It represents the worldwide experience and perspectives of experts on each method, assembled through a working group of the International Council for the Exploration of the Sea. The book is organized to foster interdisciplinary analyses and conclusions about stock structure, a crucial topic for fishery science and management. Technological advances have promoted the development of stock identification methods in many directions, resulting in a confusing variety of approaches. Based on central tenets of population biology and management needs, this valuable resource offers a unified framework for understanding stock structure by promoting an understanding of the relative merits and sensitivities of each approach. Describes 18 distinct approaches to stock identification grouped into sections on life history traits, environmental signals, genetic analyses, and applied marks Features experts' reviews of benchmark case studies, general protocols, and the strengths and weaknesses of each identification method Reviews statistical techniques for exploring stock patterns, testing for differences among putative stocks, stock discrimination, and stock composition analysis Focuses on the challenges of interpreting data and managing mixed-stock fisheries

Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 2004 with total page 928 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fish Population Dynamics in Tropical Waters written by Daniel Pauly and published by WorldFish. This book was released on 1984-01-01 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Virtual Population Analysis written by Hans Lassen and published by Food & Agriculture Org.. This book was released on 2001 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Virtual population analysis (VPA) is a widely used model for the analysis of fished populations. While there are many VPA techniques, they vary in the way they use data and fit the model rather than in the form of the model itself. This manual describes the common VPA model and the assumptions on which it is based, together with descriptions of associated diagnostic procedures and common reference points

Download or read book Fish Reproductive Biology written by Tore Jakobsen and published by John Wiley & Sons. This book was released on 2016-03-21 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fish recruitment is a key process for maintaining sustainable fish populations. In the marine environment, fish recruitment is carried out in many different ways, all of which have different life history strategies. The objective of this book is to argue for greater linkages between basic and applied research on fisheries recruitment, and assessment and management of exploited fish stocks. Following an introductory chapter, this second edition of Fish Reproductive Biology is organized into 3 main sections: Biology, Population Dynamics and Recruitment Information Critical to Successful Assessment and Management Incorporation of Reproductive Biology and Recruitment Considerations into Management Advice and Strategies The authors collectively bring a wide range of diverse experience in areas of reproductive biology, fisheries oceanography, stock assessment, and management. Fully updated throughout, the book will be of great interest to a wide audience. It is useful as a textbook in graduate and undergraduate courses in fisheries biology, fisheries science, and fisheries resource management and will provide vital information for fish biologists, fisheries scientists and managers.

Download or read book Dealing with Uncertainties in Integrated Age structured Assessment Models written by Peter-John F. Hulson and published by . This book was released on 2012 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dealing with uncertainties in integrated age-structured assessment (ASA) models has become a central focus at all levels of fish stock assessment and management. My goal in this thesis was to uncover layers of uncertainty in ASA models. There were two major components to this approach: (1) dealing with uncertainty in datasets used in ASA models through examining effective sample size, and (2) dealing with uncertainty in ASA model structure through examination of effective number of parameters and simulations of school and stock structure. From the dataset uncertainty perspective, I investigated age and length composition datasets by first identifying possible sources of error and then by evaluating if it is feasible to include this error within ASA models. From the structural uncertainty perspective, I compared historical ASA models with spatially-explicit and metapopulation scale ASA models. Sources of uncertainty in age and length composition datasets include the spatial distribution of schools and age aggregation of fish within schools. To account partially for this error at the survey design level, the optimal approach is to sample from a greater number of schools, even if the sample size within any particular school is reduced. Also, it is possible to include this error within ASA models by parameterizing and estimating effective sample size with the Dirichlet distribution. Reduced uncertainty in parameters and management quantities resulted from spatially-explicit and metapopulation ASA models when compared to historical ASA model structures. Further, with possible climate change influences on fish populations use of spatially-explicit and metapopulation ASA models will allow stock assessment scientists to accurately and more precisely predict sustainable harvest levels.

Download or read book Risk Evaluation and Biological Reference Points for Fisheries Management written by National Research Council Canada and published by NRC Research Press. This book was released on 1993 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers presented: 1) Reference points for fisheries management: the western Canadian experience; 2) Reference points for fisheries management: the eastern Canadian experience; 3) Reference points for fisheries management: the ICES experience; 4) Spawning stock biomass per recruit in fisheries management: foundation and current use; 5) The development of a management procedure for the South African anchovy resource; 6) How much spawning per recruit is enough?; 7) The behaviour of Flow, Fmed and Fhigh in response to variation in parameters used for their estimation; 8) The Barents Sea capelin stock collapse: a lesson to learn; 9) Variance estimates for fisheries assessment: their importance and how best to evaluate them; 10) Evaluating the accuracy of projected catch estimates from sequential population analysis and trawl survey abundance estimates; 11) Bootstrap estimates of ADAPT parameters, their projection in risk analysis and their retrospective patterns; 12) Analytical estimates of reliability for the projected yield from commercial fisheries; 13) Risk evaluation of the 10% harvest rate procedure for capelin in NAFO Division 3L; 14) Using jackknife and Monte Carlo simulation techniques to evaluate forecast models for Atlantic salmon; 15) Monte Carlo evaluation of risks for biological reference points used in New Zealand fishery assessments; 16) A comparison of event free risk analysis to Ricker spawner-recruit simulation: an example with Atlantic menhaden; 17) Choosing a management strategy for stock rebuilding when control is uncertain; 18) Risks and uncertainties in the management of a single-cohort squid fishery: the Falkland Islands Illex fishery as an example; 19) Risks of over- and under-fishing new resources; 20) Estimation of density-dependent natural mortality in British Columbia herring stocks through SSPA and its impact on sustainable harvesting strategies; 21) The comparative performance of production-model and ad hoc tuned VPA based feedback-control management procedures for the stock of Cape hake off the west coast of Africa; 22) A proposal for a threshold stock size and maximum fishing mortality rate; 23) Biological reference points for Canadian Atlantic gadoid stocks; 24) Stochastic locally-optimal harvesting; 25) ITQ based fisheries management; 26) Bioeconomic methods for determining TACs; 27) Management strategies: fixed or variable catch quotas; 28) Bioeconomic impacts of TAC adjustment strategies: a model applied to northern cod; 29) Experimental management programs for two rockfish stocks off British Columbia; 30)A brief overview of the experimental approach to reducing uncertainty in fisheries management; 31) Fisheries management organizations: a study of uncertainty.

Download or read book Modelling and Quantitative Methods in Fisheries written by Malcolm Haddon and published by CRC Press. This book was released on 2001-05-31 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative methods and mathematical modelling are of critical importance to fishery science and management but, until now, there has been no book that offers the sharp focus, methodological detail, and practical examples needed by non-specialist fishery scientists and managers, and ecologists. Modelling and Quantitative Methods in Fisheries fills that void. To date, methodology books in fisheries science have been limited to cookbook approach to problems; simple compilations; or expositions in which either too much theory or insufficient methodological detail is given. The text is organized into three sections: an introduction to modelling in fisheries and ecology, a straight methodology section covering a range of methods, and a section focusing on specific fields in fisheries science. This book is timely as it addresses a topic of recent debate in fisheries and ecology, describing and comparing the uses of Least Squares, Maximum Likelihood, and Bayesian quantitative methods. Designed as stand-alone units, each chapter provides examples from both classic and recent literature and comes with dedicated Excel spreadsheets that permit you to delve into every detail of the analysis. All of these spreadsheets serve as active examples, which can easily be modified and customized and can be used as templates for analyzing your own data. The spreadsheets permit you to learn at your own speed and cover the simplest linear regression to the more complex non-linear modelling using maximum likelihood. Data analysis and modelling are best learned by doing and not just by reading. This book illustrates, step by step, the analyses it covers. More detailed in terms of introductory quantitative methods and modelling as applied to fisheries than any other book available, Modelling and Quantitative Methods in Fisheries gives you the advantage by supplying the full details of the analysis so that understanding the material is a matter of following the book.

Download or read book The Future of Fisheries Science in North America written by Richard J. Beamish and published by Springer Science & Business Media. This book was released on 2009-02-07 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fisheries science in North America is changing in response to a changing climate, new technologies, an ecosystem approach to management and new thinking about the processes affecting stock and recruitment. Authors of the 34 chapters review the science in their particular fields and use their experience to develop informed opinions about the future. Everyone associated with fish, fisheries and fisheries management will find material that will stimulate their thinking about the future. Readers will be impressed with the potential for new discoveries, but disturbed by how much needs to be done in fisheries science if we are to sustain North American fisheries in our changing climate. Officials that manage or fund fisheries science will appreciate the urgency for the new information needed for the stewardship of fish populations and their ecosystems. Research organizations may want to keep some extra copies for a future look back into the thoughts of a wide range of fisheries professionals. Fisheries science has been full of surprises with some of the surprises having major economic impacts. It is important to minimize these impacts as the demand for seafood increases and the complexities of fisheries management increase.

Download or read book Fishery Science written by Lee A. Fuiman and published by John Wiley & Sons. This book was released on 2009-02-12 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is now clear that data based on the studies of fish eggs and larvae make a number of unique contributions to fishery science that are crucial for accurate assessment and management of fish populations, including those of commercially important fisheries. This valuable book demonstrates why fish eggs and larvae are important, how the characteristics of early life stages require a somewhat different research approach and how information on early life stages can be applied and interpreted to yield unique insights into fish populations. The editors of Fishery Science have drawn together an extremely useful and well-written book with contributions from internationally respected researchers from North America, Asia and Europe. Chapters include a discussion of the unique nature of early life stages, age and growth, mortality, recruitment, populations analysis, habitats, human impacts and management. A carefully selected set of case studies demonstrates several specific applications of early life history information to a number of fishery problems. Fishery Science was designed to complement existing textbooks and is an essential purchase for all fisheries students and professionals, and for biologists working on the early life stages of fish. This exciting book is also of great value to ecologists, marine, freshwater and environmental scientists, populations biologists and oceanographers. All libraries in universities and research establishments where biological and fishery science are studied and taught should have copies of this book available on their shelves.

Download or read book North American Journal of Fisheries Management written by and published by . This book was released on 1990 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Assessment of Atlantic Bluefin Tuna written by National Research Council and published by National Academies Press. This book was released on 1994-02-01 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews and evaluates the scientific basis of U.S. management of fisheries for Atlantic bluefin tuna. In particular, it focuses on the issues of stock structure and stock assessments used by the National Oceanic and Atmospheric Administration's National Marine Fisheries Service for management under the International Convention for the conservation of Atlantic Tunas.