Download or read book Population Structure of Pacific Herring in Prince William Sound written by Anthony John Gharrett and published by . This book was released on 1986* with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Population Structure of Pacific Herring Clupea Harengus Pallasi in Eastern Prince William Sound Alaska written by Charles Burkey and published by . This book was released on 1986 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Genetic Stock Structure of Herring in Prince William Sound written by Sharon L. Wildes and published by . This book was released on 2018 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examination of the genetic stock structure of Pacific herring within Prince William Sound, in comparison to those from ajacent geographic locations.
Download or read book Stock Structure and Environmental Effects on Year Class Formation and Population Trends of Pacific Herring Clupea Pallasi in Prince William Sound Alaska written by Evelyn Dale Brown and published by . This book was released on 2003 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Fluctuating forage fish populations trigger large ecosystem responses in the North Pacific. A representative species, Pacific herring, Clupea pallasi, was chosen to model environmental effects on population fluctuations and recruitment with a case example in Prince William Sound (PWS), Alaska. A unique approach was used to 1) develop a spatially-explicit, life history-based conceptual stock model, 2) quantify population level effects of climatic trends, and 3) model key environmental factors affecting recruitment. Framed as a simulation model, the stock model was compartmentalized by life-history stages based on shared habitats and environmental forcing. Initial model conditions impacting year-class formation were adult size-at-age, spawn timing, location and spawner density, and conditions during egg incubation, all impacting a two-stage larval mortality rate. Larval survival probably dictates the extremes in year-class strength. Age-1 abundance should reflect recruitment levels 2-3 yrs later, unless a predator pit exists. A metapopulation structure was proposed with at least two local population groupings with spatial complexity required to maintain stock levels. Herring abundance correlated with long-term climate trends supporting hypotheses of bottom up environmental forcing. Adult growth was oscillatory over a 13 yr period in phase with zooplankton production and climatic trends. Spawn timing occurred progressively earlier over the last 30 yr period with a concurrent regional spawn allocation shift and decrease in recruits per spawner. Incorporating local stock structure and local environmental variables into nonlinear herring recruitment models improved explanatory power over traditional models. Best-fit variables were eastern PWS SST, salinity, SST variance, and salinity variance from spring to fall. Eight critical life stage periods were defined based on the season and lag of the best-fitting varibles. Examining other variables in these critical periods led to defining potential key processes affecting year class formation. Allocation of spawn and age-3 recruits to metapopulation regions also impacted recruitment to PWS as a whole and these results supported the metapopulation theory. The results led to formulation of a new theory, entitled 'opposing response', explaining the mechanism producing the observed pattern of alternating strong and week year class strengths in northern Pacific herring"--Leaves iii-iv.
Download or read book Modeling the Population Dynamics of Prince William Sound Herring written by Trevor A. Branch and published by . This book was released on 2018 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A stock-age assessment model of Prince William Sound Pacific herring, utilizing data collected from 2102-2017. It was determined that the use of a Bayesian model to be an effective means of estimating ongoing biomass trends in the herring population.
Download or read book Historic Database for Pacific Herring in Prince William Sound Alaska 1973 1991 written by Alaska. Division of Commercial Fisheries and published by . This book was released on 1992 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes corrected and finalized historic data on abundance, age, sex, and size for Pacific herring (Clupea pallasi) in Prince William Sound. Includes aerial survey estimates of biomass and shoreline miles of spawn; the data are summarized by five major areas of spawning: Northeast, Southeast, North Shore, Naked Island and the Montague Island areas.
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 Age Composition Weight Length and Sex of Herring Clupea Pallasii Used for Reduction in Alaska 1929 66 written by Gerald M. Reid and published by . This book was released on 1971 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stock Assessment and Management of Pacific Herring in Prince William Sound Alaska 1990 written by Timothy T. Baker and published by . This book was released on 1991 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling and Stock Assessment of Prince William Sound Pacific Herring written by Trevor A. Branch and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report on the ongoing monitoring of the Pacific herring population in the Prince William Sound in the aftermath of the Exxon Valdez Oil Spill. The report outlines ongoing projects including annual stock assessments using a Bayesian model, an assessment of disease data, analysis of factors affecting natural mortality and recruitment, a study on changes in spawning patterns, and testing of hypotheses for changes in spawning timing.
Download or read book Investigations of Disease Factors Affecting Declines of Pacific Herring Populations in Prince William Sound written by Gary D. Marty and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations of Disease Factors Affecting Declines of Pacific Herring Populations in Prince William Sound written by Richard M. Kocan and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Early Life History of Pacific Herring Prince William Sound Herring Larvae Survey written by Michael Douglas McGurk and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study measured growth, mortality, and dispersal of wild Pacific herring larvae from 2 oiled sites and 2 non-oiled sites in Prince William Sound in order to determine the impact of the Exxon Valdez oil spill on larval population.
Download or read book Growth of Pacific Herring in Prince William Sound Alaska from 1973 Through 1987 written by Fritz Funk and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Juvenile Herring Abundance Index written by Peter S. Rand and published by . This book was released on 2018 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of acoustic surveys to monitor the population of juvenile Pacific herring in Prince William Sound, Alaska, taking place from 2012 to 2016.
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.
