Download or read book An Examination of Criteria for Determining the Age of Pacific Cod Gadus Macrocephalus from Otoliths written by Fisheries Research Board of Canada and published by ottawa : queen's printer. This book was released on 1970 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Age Determination of Alaska Pacific Cod Gadus Macrocephalus written by Nancy Elizabeth Roberson and published by . This book was released on 2001 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Progress Report on Validating Age Determination Methods for Pacific Cod Gadus Macrocephalus written by S. J. Westrheim and published by . This book was released on 1982 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes the progress in re-examining the criteria for reading fish scales, and comparing scale and fin-ray readings from the same fish.
Download or read book Age Determination Manual of the Alaska Fisheries Science Center Age and Growth Program written by Mary Elizabeth Matta and published by . This book was released on 2012 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Age Determination Methods for Fishes Studied by the Groundfish Program at the Pacific Biological Station written by D. E. Chilton and published by Government of Canada, Fisheries and Oceans, Scientific Information and Publications Branch. This book was released on 1982 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Proceedings of an International Symposium on the Ageing of Fish written by T. B. Bagenal and published by . This book was released on 1974 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spatial and Temporal Distribution and Relative Abundance of Pacific Cod Gadus Macrocephalus Larvae in the Western Gulf of Alaska written by William C. Rugen and published by . This book was released on 1988 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fishery Bulletin written by and published by . This book was released on 1987 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report written by and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin International North Pacific Fisheries Commission written by and published by . This book was released on 1990 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report Fisheries Research Board of Canada written by and published by . This book was released on 1971 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin International North Pacific Fisheries Commission written by International North Pacific Fisheries Commission and published by . This book was released on 1985 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of the Fisheries Research Board of Canada written by Fisheries Research Board of Canada and published by . This book was released on 1970 with total page 910 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Otolith Weight in Age Determination of Baltic Cod written by and published by Nordic Council of Ministers. This book was released on 2008 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Canadian Special Publication of Fisheries and Aquatic Sciences written by and published by . This book was released on 1982 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Natal Source Contributions of Pacific Cod Gadus Macrocephalus Recruits in the Southeastern Bering Sea written by Ruth A. DiMaria and published by . This book was released on 2011 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effective and sustainable fisheries management not only depends on identifying and defining stocks (fundamental unit of management), but also on having knowledge of factors influencing the abundance, distribution and connectivity of stocks. Population structure of Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea (EBS) remains unresolved although genetic data indicate isolation-by-distance throughout the species range across the North Pacific Ocean. Pacific cod are fished on their spawning grounds, therefore, it is important to evaluate whether particular spawning sources are more critical than others in sustaining the productivity of fished populations. Chemical analysis of otoliths can provide information on mixing among groups of fish on ecological time scales and at finer spatial scales than genetic analyses. Therefore, I completed laboratory and field research on the otolith elemental composition of larval and juvenile cod to: (1) investigate temperature and growth-rate effects on otolith elemental incorporation to aid interpretations of field data; (2) evaluate the potential to detect larval exchange between the Gulf of Alaska (GOA) and the EBS; (3) quantify spatial scales at which there was significant variation in otolith elemental composition; and (4) quantify the number of larval sources (chemically distinct groups) contributing to juvenile recruits in the EBS. In the laboratory study, I observed higher rates of incorporation at lower temperatures for both Sr and Ba but similar ranges of Mg incorporation at 2°C, 6°C and 8°C. There was no significant effect of somatic growth or otolith precipitation rate on elemental incorporation detected, indicating that variation in individual growth rates should not confound interpretations of field data. In two years of field collections (2006 & 2008), otolith elemental signatures (Mg:Ca, Mn:Ca, Zn:Ca, Sr:Ca, and Ba:Ca) differed between larvae collected in the EBS and GOA, and over 70% of the larvae were correctly classified to source. Furthermore, I examined the chemical signatures of the otolith edge (representing approximately the last 10 d of life) for juveniles collected at six locations throughout the EBS. Seventy-nine and 71% of the juveniles were correctly classified to their collection location in 2006 and 2008, respectively. These results demonstrate that there is sufficient spatial variation in otolith composition to examine spatial structure in Pacific cod within the EBS and to identify GOA larval contribution to the EBS population. Finally, larval source signatures, represented by otolith core chemistry, of juveniles collected throughout the EBS were classified into chemically distinct groups using hierarchical cluster analysis. In both years we identified two dominant sources representing 56% and 30% of the cohort in 2006, and 53% and 40% in 2008. Most collection sites contained a mixture of larval sources although one or two sites per year were comprised of a single source. These chemically unique sources likely represent different spawning locations with distinct environmental characteristics, although the exact locations are unknown. These sources potentially represent contributions from known spawning areas, which include the Alaskan Peninsula, Aleutian Islands, and Pribilof Islands. Our results highlight the potential of otolith chemical analyses to identify source contributions of Pacific cod in the EBS but larval collections throughout the spawning season are needed to provide additional detail on the spatial distribution of those sources.
