Age Determination Manual Of The Alaska Fisheries Science Center Age And Growth Program

The Age and Growth Program at the Alaska Fisheries Science Center is tasked with providing age data in order to improve the basic understanding of the ecology and fisheries dynamics of Alaskan fish species. The primary focus of the Age and Growth Program is to estimate ages from otoliths and other calcified structures for age-structured modeling of commercially exploited stocks; however, the program has recently expanded its interests to include numerous studies on topics ranging from age estimate validation to the growth and life-history of non-target species. Because so many applications rely upon age data and particularly upon assurances as to their accuracy and precision, the Age and Growth Program has developed this practical guide to document the age determination of key groundfish species from Alaskan waters. The main objective of this manual is to describe techniques specific to the age determination of commercially and ecologically important species studied by the Age and Growth Program. The manual also provides general background information on otolith morphology, dissection, and preparation, as well as descriptions of methods used to measure precision and accuracy of age estimates. This manual is intended not only as a reference for age readers at the AFSC and other laboratories, but also to give insight into the quality of age estimates to scientists who routinely use such data.

The Age and Growth Program at the Alaska Fisheries Science Center is tasked with providing age data in order to improve the basic understanding of the ecology and fisheries dynamics of Alaskan fish species. The primary focus of the Age and Growth Program is to estimate ages from otoliths and other calcified structures for age-structured modeling of commercially exploited stocks; however, the program has recently expanded its interests to include numerous studies on topics ranging from age estimate validation to the growth and life-history of non-target species. Because so many applications rely upon age data and particularly upon assurances as to their accuracy and precision, the Age and Growth Program has developed this practical guide to document the age determination of key groundfish species from Alaskan waters. The main objective of this manual is to describe techniques specific to the age determination of commercially and ecologically important species studied by the Age and Growth Program. The manual also provides general background information on otolith morphology, dissection, and preparation, as well as descriptions of methods used to measure precision and accuracy of age estimates. This manual is intended not only as a reference for age readers at the AFSC and other laboratories, but also to give insight into the quality of age estimates to scientists who routinely use such data.

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

This manual describes methods and equipment used to estimate the ages of groundfish species studied by the Pacific Biological Station. Procedures for routine identification of annuli on scales, otoliths, otolith section, fin-ray sections, and spines are described and illustrated. Although the techniques are applied to species found off Canada's west coast, they should be applicable to other marine and freshwater fishes from temperate and arctic waters. Because some of the procedures are experimental and many have not been validated, it is expected that this manual will be revised several times.

The field of otolith microstructure research has experienced phenomenal growth since the early 1970s and now forms the basis for hundreds of studies in early life history, age, growth, recruitment, migration, mortality and stock structure. This book represents the first effort to compile and summarize the many techniques and procedures associated with studies of otolith microstructure. The complete sequence of events, from sample collection to data analysis, is covered comprehensively, so as to be applicable to most species and situations. The various chapters include both published and unpublished procedures.