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EBookClubs

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Book Alaska Fishery Research Bulletin

Download or read book Alaska Fishery Research Bulletin written by and published by . This book was released on 1997 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fishery Stock Assessment Models

Download or read book Fishery Stock Assessment Models written by Fritz Funk and published by Alaska Sea Grant College Program. This book was released on 1998 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume bring fisheries modelers up to date on stock assessment modeling as a research tool. It has 55 peer-reviewed papers from all parts of the world, presented at the 1997 symposium Fishery Stock Assessment Models for the 21st Century, in Anchorage, Alaska.

Book Interrelationships of Pacific Herring Clupea Pallasi Populations and Their Relation to Large scale Environmental and Oceanographic Variables

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.

Book Preliminary Forecasts of Catch and Stock Abundance for 1990

Download or read book Preliminary Forecasts of Catch and Stock Abundance for 1990 written by Fritz Funk and published by . This book was released on 1990 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Stock Assessment for British Columbia Herring in 1992 and Forecasts of the Potential Catch in 1993

Download or read book Stock Assessment for British Columbia Herring in 1992 and Forecasts of the Potential Catch in 1993 written by Canada. Department of Fisheries and Oceans and published by . This book was released on 1993 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Age Structured Analysis of Pacific Herring from Norton Sound Alaska

Download or read book Age Structured Analysis of Pacific Herring from Norton Sound Alaska written by Erik H. Williams and published by . This book was released on 1996 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Age-structured assessment models are used for many exploitable herring stocks in Alaska in order to forecast the abundance of returning herring. The purpose of this study is to determine if an age-structured assessment model could be developed for Norton Sound herring. Commercial catch and sampling data for Norton Sound herring were obtained from the Alaska Department of Fish and Game. Natural mortality estimates were obtained from analysis of life history parameters. Initial starting values for the age-structured model weere obtained from cohort analysis. Two types of models, with and without a pooled age group, were fit to the data. A parametric bootstrap analysis utilizing a beta distribution fit to observed age compositions was performed in order to obtain standart deviations of the estimates. Model fits indicated that inclusion of a pooled age group (10+) worked best. The fit of this model to the data is comparable to previous age-structured assessments of Alaska herring stocks." -- from the Abstract.

Book Stock Assessments for British Columbia Herring in 1991 and Forecasts of the Potential Catch in 1992

Download or read book Stock Assessments for British Columbia Herring in 1991 and Forecasts of the Potential Catch in 1992 written by and published by . This book was released on 1992 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Herring are an important component of the British Columbia commercial fishery with catch records dating from 1877. Since 1983, herring fisheries have been managed with a fixed quota system in which catch levels are determined prior to the season based on a fixed percentage of forecast stock abundance. This report presents stock assessments from escapement and age-structured analytical models that were developed explicitly for B.C. herring. Both models reconstruct stock abundance for 1951-91 and forecast pre-spawning abundance for 1992. Forecasts of recruit spawners are presented as poor, average and good, based on historical recruitment levels. The report does not discuss the development and evaluation of empirical models for forecasting recruitment.

Book Forecast of the Pacific Herring Biomass in Prince William Sound Alaska 1993

Download or read book Forecast of the Pacific Herring Biomass in Prince William Sound Alaska 1993 written by Fritz Funk and published by . This book was released on 1994 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: "An egg structured assessment (ASA) model is used to forecast the abundance of herring expected to return to spawn in Prince William Sound in 1993. The ASA model develops 1973-92 biomass estimates by smoothing differences in abundance trends suggested by spawn deposition surveys, aerial milt surveys, and the time series of purse seine, gillnet, and spawning age composition samples"--Page vi.

Book Stock Assessments for British Columbia Herring in 1990 and Forecasts of the Potential Catch in 1991

Download or read book Stock Assessments for British Columbia Herring in 1990 and Forecasts of the Potential Catch in 1991 written by V. Haist and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents stock assessments from an escapement model and an age-structured model developed specifically for B.C. herring. Both models reconstruct stock abundance for 1951-90 and forecast pre-spawning abundance for the 1991 season. Forecasts of recruit spawners are presented as poor, average, and good based on historically observed means.