958 results on '"Thorson, James"'
Search Results
102. Thirteen novel ideas and underutilised resources to support progress towards a range‐wide American eel stock assessment
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Cairns, David K., primary, Benchetrit, José, additional, Bernatchez, Louis, additional, Bornarel, Virginie, additional, Casselman, John M., additional, Castonguay, Martin, additional, Charsley, Anthony R., additional, Dorow, Malte, additional, Drouineau, Hilaire, additional, Frankowski, Jens, additional, Haro, Alex, additional, Hoyle, Simon D., additional, Knickle, D. Craig, additional, Koops, Marten A., additional, Poirier, Luke A., additional, Thorson, James T., additional, Young, John, additional, and Zhu, Xinhua, additional
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- 2022
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103. Competing Interests, Economics, and Marine Fisheries Management: An Educational Case Study
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Thorson, James T., Berkson, Jim, and Murphy, Brian
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Managing fish resources in the ocean, known as marine fisheries management, often involves disagreement among many groups of people: commercial fishers, recreational anglers, national and local conservationists, and several branches of government. While managing marine fisheries in federal waters, the federal government must rebuild marine fish populations while balancing the economic demands of these competing groups. Red snapper ("Lutjanus campechanus") is a particularly useful example, involving more than 200,000 people and $80 million each year in the Gulf of Mexico. After a lawsuit won by conservation groups in 2007, the National Marine Fisheries Service was required to tighten management while selecting from many possible management tools. We envision that students will read this case study and participate in classroom discussion using the questions and teaching notes that are included. Students will then be divided between recreation and commercial user groups, and will advocate for their user group in a classroom role play in an attempt to persuade a third group: student resource managers. These student resource managers will ultimately select a set of allocation and management actions for the red snapper fishery that will decrease total catch as required by the 2007 court case, which can be compared with real-world decisions. This study aims to illustrate the complex conflicts and economic issues that surround fisheries management decisions. The learning objectives are: (1) to develop and demonstrate students' ability to craft arguments in a debate, and (2) to build student experience working as a team doing research and planning an argument. (Contains 7 exhibits.)
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- 2010
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104. Using a recruitment-linked multispecies stock assessment model to estimate common trends in recruitment for US West Coast groundfishes
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Thorson, James T., Stewart, Ian J., Taylor, Ian G., and Punt, André E.
- Published
- 2013
105. Do large‐scale associations in birds imply biotic interactions or environmental filtering?
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Elo, Merja, Kajanus, Mira H., Tolvanen, Jere, Devictor, Vincent, Forsman, Jukka T., Lehikoinen, Aleksi, Mönkkönen, Mikko, Thorson, James T., Vollstädt, Maximilian G. R., and Kivelä, Sami M.
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SPECIES distribution ,HABITAT selection ,FILTERS & filtration ,COMPETITION (Biology) ,HABITATS - Abstract
Aim: There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within‐trophic‐level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis‐testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location: France and Finland. Taxon: Birds. Methods: We estimated species‐to‐species associations within a trophic level, independent of the main environmental variables (mean temperature and total precipitation) for common species at large spatial scale with joint dynamic species distribution (a multivariate spatiotemporal delta model) models. We created hypotheses based on species' functionality (morphological and/or diet dissimilarity) and habitat preferences about the sign and strength of the pairwise spatiotemporal associations to estimate the extent to which they result from biotic interactions (competition, heterospecific attraction) and/or environmental filtering. Results: Spatiotemporal associations were mostly positive (80%), followed by random (15%), and only 5% were negative. Where detected, negative spatiotemporal associations in different communities were due to a few species. The relationship between spatiotemporal association and functional dissimilarity among species was negative, which fulfils the predictions of both environmental filtering and heterospecific attraction. Main conclusions We showed that processes leading to species aggregation (mixture between environmental filtering and heterospecific attraction) seem to dominate assembly rules, and we did not find evidence for competition. Altogether, our hypothesis‐testing framework based on joint dynamic species distribution models and functional trait similarity is beneficial in ecological interpretation of species‐to‐species associations from data covering several decades and biogeographical regions. [ABSTRACT FROM AUTHOR]
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- 2023
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106. Evaluating population recovery for sea turtles under nesting beach protection while accounting for nesting behaviours and changes in availability
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Thorson, James T., Punt, André E., and Nel, Ronel
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- 2012
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107. Spatial semiparametric models improve estimates of species abundance and distribution
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Shelton, Andrew Olaf, Thorson, James T., Ward, Eric J., and Feist, Blake E.
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Animal populations -- Distribution ,Biological diversity conservation -- Management ,Fishery management ,Company business management ,Company distribution practices ,Earth sciences - Abstract
Accurate estimates of abundance are imperative for successful conservation and management. Classical, stratified abundance estimators provide unbiased estimates of abundance, but such estimators may be imprecise and impede assessment of population status and trend when the distribution of individuals is highly variable in space. Model-based procedures that account for important environmental covariates can improve overall precision, but frequently there is uncertainty about the contribution of particular environmental variables and a lack of information about variables that are important determinants of abundance. We develop a general semiparametric mixture model that incorporates measured habitat variables and a nonparametric smoothing term to account for unmeasured variables. We contrast this spatial habitat approach with two stratified abundance estimators and compare the three models using an intensively managed marine fish, darkblotched rockfish (Sebastes crameri). We show that the spatial habitat model yields more precise, biologically reasonable, and interpretable estimates of abundance than the classical methods. Our results suggest that while design-based estimators are unbiased, they may exaggerate temporal variability of populations and strongly influence inference about population trend. Furthermore, when such estimates are used in broader meta-analyses, such imprecision may affect the broader biological inference (e.g., the causes and consequences of the variability of populations). Des estimations exactes de l'abondance sont essentielles au succes de la conservation et de la gestion. Si les estimateurs d'abondance stratifies classiques fournissent des estimations non biaisees de l'abondance, ces estimateurs peuvent etre imprecis ou entraver l'evaluation de l'etat et de la tendance de la population si la repartition des individus est tres variable dans l'espace. Si des procedures basees sur des modeles qui tiennent compte d'importantes covariables environnementales peuvent ameliorer la precision globale, il y a souvent une incertitude associee a la contribution de differentes variables environnementales et un manque d'information sur les variables qui sont d'importants determinants de l'abondance. Nous avons developpe un modele de melange semi-parametrique general qui incorpore des variables mesurees de l'habitat et un terme de lissage non parametrique pour tenir compte des variables non mesurees. Nous comparons cette approche d'habitat spatial a deux estimateurs d'abondance stratifies a la lumiere d'observations sur un poisson marin faisant l'objet d'une gestion intensive, le sebaste tachete (Sebastes crameri). Nous demontrons que le modele d'habitat spatial produit des estimations de l'abondance plus precises, interpretables et raisonnables du point de vue biologique que les methodes classiques. Nos resultats donnent a penser que, si les estimateurs bases sur la conception de l'echantillonnage sont non biaises, ils peuvent exagerer la variabilite temporelle des populations et influencer fortement l'inference concernant la tendance demographique. En outre, quand ces estimations sont utilisees dans des metaanalyses plus larges, cette imprecision pour avoir une incidence sur l'inference biologique elargie (p. ex. les causes et consequences de la variabilite des populations). [Traduit par la Redaction], Introduction Accurate assessment of population status and trend are fundamental to the successful conservation and management of species. Imprecise or biased estimates of population biomass or abundance may cause managers [...]
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- 2014
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108. Understanding transboundary stocks’ availability by combining multiple fisheries-independent surveys and oceanographic conditions in spatiotemporal models
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O'Leary, Cecilia A, primary, DeFilippo, Lukas B, additional, Thorson, James T, additional, Kotwicki, Stan, additional, Hoff, Gerald R, additional, Kulik, Vladimir V, additional, Ianelli, James N, additional, and Punt, André E, additional
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- 2022
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109. sdmTMB: An R Package for Fast, Flexible, and User-Friendly Generalized Linear Mixed Effects Models with Spatial and Spatiotemporal Random Fields
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Anderson, Sean C., primary, Ward, Eric J., additional, English, Philina A., additional, Barnett, Lewis A. K., additional, and Thorson, James T., additional
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- 2022
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110. Diet analysis using generalized linear models derived from foraging processes using R packagemvtweedie
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Thorson, James T., primary, Arimitsu, Mayumi L., additional, Levi, Taal, additional, and Roffler, Gretchen H., additional
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- 2022
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111. Combining scientific survey and commercial catch data to map fish distribution
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Alglave, Baptiste, primary, Rivot, Etienne, additional, Etienne, Marie-Pierre, additional, Woillez, Mathieu, additional, Thorson, James T, additional, and Vermard, Youen, additional
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- 2022
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112. Identifying species complexes based on spatial and temporal clustering from joint dynamic species distribution models
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Omori, Kristen L, primary and Thorson, James T, additional
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- 2022
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113. A spatial statistical approach for identifying population structuring of marine fish species: European sprat as a case study
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Lindegren, Martin, primary, van Deurs, Mikael, additional, Maureaud, Aurore, additional, Thorson, James T, additional, and Bekkevold, Dorte, additional
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- 2022
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114. Titmice are a better indicator of bird density in Northern European than in Western European forests
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Kajanus, Mira H., primary, Forsman, Jukka T., additional, Vollstädt, Maximilian G. R., additional, Devictor, Vincent, additional, Elo, Merja, additional, Lehikoinen, Aleksi, additional, Mönkkönen, Mikko, additional, Thorson, James T., additional, and Kivelä, Sami M., additional
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- 2022
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115. Impacts of fisheries-dependent spatial sampling patterns on catch-per-unit-effort standardization: A simulation study and fishery application
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Ducharme-Barth, Nicholas D., primary, Grüss, Arnaud, additional, Vincent, Matthew T., additional, Kiyofuji, Hidetada, additional, Aoki, Yoshinori, additional, Pilling, Graham, additional, Hampton, John, additional, and Thorson, James T., additional
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- 2022
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116. New Wrinkles on Retirement: Program Notes.
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Georgia Univ., Athens. Georgia Center for Continuing Education., Wray, Robert P., and Thorson, James A.
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The program notes were prepared to accompany the television series "New Wrinkles on Retirement." The eight units in the series are: facing inflation, which covers the decreasing value of the dollar, transportation costs, medical expenses, cutting expenses, family budgeting, investments, and places to live; vigor regained, which covers exercise and other health practices, good nutrition, and regular health checkups; a time to learn and a time to play, which covers constructive activity and hobbies, helping others, political involvement, and learning for pleasure; marriage and love, which covers marriage structure and function, relationships with children, adjustment to new roles, and mutual understanding; confronting loss, which covers loss of a spouse, loneliness, widowhood, and remarriage; your legacy, which covers wills and estates, trusts and insurance, and legal problems in retirement; quacks and frauds, which covers avoiding con-men and not being victimized by crime; and maintaining happiness, which covers keeping a healthy outlook on life and maintaining mental and physical health. Two appendixes are included: one, a bibliography of selected sources of information and the other, a list of places to live. (JR)
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- 1975
117. Political Responses to Aging.
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Georgia State Univ., Atlanta., Georgia Univ., Athens., Thorson, James A., and Payne, Barbara P.
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The proceedings of the First Annual Georgia Conference on Aging contains five papers, reports from discussion groups, and transcripts of a panel discussion. The focus was on the encouragement of self-advocacy and the identification of achievable goals among older adults in order to generate some of the basic political changes that will improve the life chances of the elderly. The proceedings' contents include: Introduction, Barbara P. Payne; The Development of Services for Older Georgians, Mary Kay Jernigan; Contributions to the Quality of Older Persons' Lives: Realistic Expectations, Frank Hughes; Political Responses of the Aged: Research Findings, Robert H. Binstock; Achievable Goals for Older Georgians: Reports from Discussion Groups; The Senior Center and the City of Atlanta, a Panel Discussion, Al Horvath, moderator; The Revolution of the Elders, Margaret E. Kuhn; and The Future of Contributions to the Quality of Older Persons' Lives, David G. Salten. (JR)
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- 1974
118. Variations in Attitude Toward Aging as a Function of Educational Level.
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Thorson, James A.
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The study reports on the use of the Kogan Old People (OP) scale, a 34-item Likert scale, in a variety of research applications. In the study's first phase, 59 subjects from three different training programs dealing with the elderly completed the OP scale. The results of this phase indicated that attitude toward old people became more negative as age of respondent increased. From these results it was hypothesized that race and social class might also affect attitudes toward old people. In phase two a group of high school students, all at nearly the same age and educational level, completed the OP scale. Grouping the respondents according to race and class produced no consistent pattern of differences in mean scores. Grouping the two samples indicated that no consistent pattern or increase in positive attitudes can be demonstrated by subjects' age. However, respondents having one or more years of higher education had a more positive attitude than the non-college group. Thus, among the groups tested, years of education appears to be an important factor contributing to variation in attitudes toward the aged. Sampling procedures were not random, so the results are not generalizable to a larger population. (JR)
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- 1975
119. Attitudes Toward the Aged as a Function of Race and Social Class.
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Thorson, James A.
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Studies have indicated that subjects with more years of education show a positive attitude toward older persons. The present study investigated the effects of other variables, in this case race and social class, in relation to attitudes toward older persons. A sample group of high school juniors and seniors whose ages ranged from 16 to 18 were given a questionnaire based on the Kogan Attitudes Toward Old People Scale. The subjects consisted of 48 blacks and 50 whites; 46 belonged to the lower income class and 52 to the middle income class. The results of the study showed almost no effect on attitudes toward older people based on race and social class. Combining data from this study with a previous study giving a total of 194 subjects showed a relationship between number of years of education and a more positive attitude towards the elderly. The tabulated scores and a list of references are included. (EC)
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- 1974
120. Variations in Attitudes Toward the Aged Held by Selected Groups in the Southern United States.
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Thorson, James A.
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A three-part study has been conducted over the past several years to isolate and describe correlates of attitudes toward the elderly. The paper briefly summarizes the first two parts of the study and concentrates on its concluding portion. Data from the first part of the study indicated that younger and more well-educated subjects displayed more positive attitudes toward the elderly. Data from the second part of the study showed little relationship between the variables race and socioeconomic status and attitudes toward the aged. The third part of the study tested for relationships between personality characteristics and attitudes toward old people. It was hypothesized that persons high in the trait of nurturance would have more positive attitudes toward the elderly. Data collected using the Edwards Personal Preference Scale showed positive attitudes correlated with high scores for the traits of intraception, nurturance, and endurance. However, demographic factors seem to be more important determinants of attitudes toward old people than are the personality items. Data indicate that females, subjects who are older, and subjects having a higher number of years of education have more positive attitudes toward old people. A list of references is included. (Author/EC)
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- 1975
121. A Factor Analytic Study of a Scale Designed to Measure Death Anxiety.
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Thorson, James A. and Perkins, Mark
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A death anxiety scale developed in 1973 by Nehrke was administered to 655 adult subjects. Their responses were differentiated according to age, sex, race, and level of education. Data were also analyzed using the varimax rotated factor matrix procedure to determine significant factors that the scale was, in fact, measuring. Loadings on four distinct factors accounted for 92.7% of the variance measured by the scale: fear of isolation and immobility, fear of pain, fear of the future, and fear of physical decomposition. Analyses variance revealed that older respondents had significantly less death anxiety as measured by this scale than did younger subjects. Males indicated significantly less death anxiety than did females in this sample. No differences in death anxiety were found by race or educational level. A number of recommendations are made for further modification and revision of the scale. (Author/MFD)
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- 1977
122. Mannerisms of the Elderly and Approaches to Rapport.
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French, Warren A. and Thorson, James A.
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This study presents a set of opinions on how to obtain rapport with and give preliminary counseling to individuals who have adopted distinct and different aging mannerisms. The nine mannerisms treated were abstracted from the studies of Neugarten and Reichard. The research sample was selected from the members of the Gerontological Society. Six forms of the final research instrument were created, each containing three of the nine behavioral mannerisms. Each mannerism appeared on two of the six forms. Combinations of any two stereotypes appeared only once in the six forms. The sample was asked to: (1) estimate the percentages of the elderly population that could be described by the three stereotypes, (2) recommend the best way to attain rapport with and resolve the problems of each group, and (3) suggest motivating appeals for making changes. Regardless of type of behavior senior citizens exhibited, there were three universal rules that the gerontologists laid down for the rapport and counseling process. (1) Individual people deserve individual attention. (2) Every person, irrespective of state of mind or background, must be treated with dignity and respect. (3) Listen, observe and empathize before making suggestions. Recommendations for each of the mannerisms are presented. (Author)
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- 1977
123. Workers with Special Needs: An Overview. Module I. Job Match: Together for Good Business.
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Nebraska Univ., Omaha. Center for Applied Urban Research., Thorson, James A., and Faison, Karen
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Intended for use with business and industry personnel, the training module is part of a kit designed to demonstrate how individuals with disabilities and older persons can be assimilated successfully into the labor force. This module provides an overview of the problems of persons with disabilities and older workers. It defines each of these groups, discusses common myths and stereotypes, provides factual information on actual performance, explains the major issues affecting these workers, and lists the benefits of hiring individuals with special needs for the individuals themselves, for employers, and for society. An introduction explains how to use the module providing information on desired competency of participants in the training sessions, the target audience, instructional objectives, materials, preparation, and sequence of instruction. An appendix provides definitions of major physical and mental disabilities. About 75 references. (DB)
- Published
- 1987
124. Development and simulation testing for a new approach to density dependence in species distribution models
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Thorson, James T, primary
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- 2021
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125. The Role of Climate, Oceanography, and Prey in Driving Decadal Spatio-Temporal Patterns of a Highly Mobile Top Predator
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Astarloa, Amaia, primary, Louzao, Maite, additional, Andrade, Joana, additional, Babey, Lucy, additional, Berrow, Simon, additional, Boisseau, Oliver, additional, Brereton, Tom, additional, Dorémus, Ghislain, additional, Evans, Peter G. H., additional, Hodgins, Nicola K., additional, Lewis, Mark, additional, Martinez-Cedeira, Jose, additional, Pinsky, Malin L., additional, Ridoux, Vincent, additional, Saavedra, Camilo, additional, Santos, M. Begoña, additional, Thorson, James T., additional, Waggitt, James J., additional, Wall, Dave, additional, and Chust, Guillem, additional
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- 2021
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126. How variable is recruitment for exploited marine fishes? A hierarchical model for testing life history theory
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Thorson, James T., Jensen, Olaf P., and Zipkin, Elise F.
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Animal experimentation -- Evaluation ,Marine fishes -- Usage ,Earth sciences - Abstract
Recruitment often varies substantially in fish populations, and residual variability may have serial autocorrelation due to environmental effects even after accounting for a stock-recruitment relationship. However, the likely magnitude of variability and autocorrelation in recruitment has yet to be formally estimated. We therefore developed a hierarchical model for recruitment variability and autocorrelation and applied it to data for 154 fish populations. Results were similar when using either the Ricker or Beverton-Holt stock-recruitment model, and showed that autocorrelated recruitment has a marginal standard deviation of 0.74 (SD = 0.35) and a mean autocorrelation of 0.43 (SD = 0.28) when predicting for an unobserved taxonomic order. Estimates differed somewhat among taxonomic orders and stocks, and also supported a hypothesized positive relationship between age at maturity and autocorrelation in recruitment. Our results can be used as a Bayesian prior for recruitment variability in models for data-poor stocks and to distinguish recruitment from other process errors in models for data-rich stocks. Estimates can also be used in the design of future simulation models and management strategy evaluations and in theoretical research regarding life history variation. Le recrutement varie souvent beaucoup au sein de populations de poissons, la variability residuelle pouvant presenter une autocorrelation serielle decoulant d'effets ambiants meme apres la prise en consideration de la relation stock-recrutement. La magnitude probable de la variability et de l'autocorrelation du recrutement n'a toutefois pas encore ete estimee formellement. Nous avons donc mis au point un modele hierarchique pour estimer la variabilite et l'autocorrelation du recrutement et l'avons applique a des donnees pour 154 populations de poissons. Les resultats sont semblables a ceux obtenus avec les modeles stock-recrutement de Ricker ou de Beverton-Holt et montrent que le recrutement autocorrele presente un ecart-type marginal de 0,74 (ET = 0,35) et une autocorrelation moyenne de 0,43 (ET = 0,28) pour la prediction d'un ordre taxonomique non observe. Les estimations different quelque peu selon l'ordre taxinomique et le stock et appuient egalement l'hypothese d'une relation positive entre l'age a la maturite et l'autocorrelation dans le recrutement. Nos resultats peuvent etre utilises comme a priori bayesien pour la variabilite du recrutement dans les modeles de stocks pour lesquels peu de donnees sont disponibles, et pour distinguer le recrutement d'autres erreurs de traitement dans les modeles de stocks pour lesquels les donnees sont abondantes. Les estimations peuvent egalement etre utilisees pour concevoir de nouveaux modeles de simulation et Revaluation de strategies de gestion, ainsi qu'en recherche theorique sur les variations du cycle biologique. [Traduit par la Redaction], Introduction Early research in fisheries science showed that cohorts within a population can have large differences in relative abundance (Hjort 1926). Subsequent research has shown that cohort strength can differ [...]
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- 2014
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127. Action Now for Older Americans: Toward Independent Living.
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Georgia Univ., Athens. Georgia Center for Continuing Education. and Thorson, James A.
- Abstract
The collection of conference papers given by representatives of State, Federal, and voluntary agencies, and university faculty, discusses information and planning strategies aimed at maximizing independent living for the elderly. Introductory and welcoming remarks by James A. Thorson, Virginia Smith, and Frank Groschelle are included along with the full texts of the following papers: Advocacy for the Older Person, Carl Eisdorfer; Regional Directions in Serving Older Americans, Frank Nicholson; Action Toward Maximizing Independent Living for Older Americans; Ray Schwartz; The Role of the National Voluntary Agencies, Ellen Winston; Problems of Handicapped Older Citizens in Maintaining Independent Living, E. Percil Stanford; New Thrusts in Services, Goals, Barriers, and Some Solutions in Helping the Aged Toward Independent Living, James J. Burr; New Strategies for Serving Older People, Charles Wells; The Goal and Objective, Stanley Brody; Strategies to Identify and Serve the Target Groups, Margaret Blenkner; The Impact of Scientific Advances on Independent Living, Carl Eisdorfer; Services to Maintain Older People in Their Homes, William G. Bell; Strategies in Providing Services to the Elderly, Carter Osterbind. Working through the agencies of the Department of Health, Education and Welfare (DHEW), the National Voluntary Organizations, and regional and State programs is emphasized. (LH)
- Published
- 1972
128. A new role for effort dynamics in the theory of harvested populations and data-poor stock assessment
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Thorson, James T., Minto, Coilin, Minte-Vera, Carolina V., Kleisner, Kristin M., and Longo, Catherine
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Animal populations -- Distribution ,Population biology -- Research ,Fisheries -- Management ,Fish industry -- Management ,Company business management ,Company distribution practices ,Earth sciences - Abstract
Research shows that population status can be predicted using catch data, but there is little justification for why these predictions work or how they account for changes in fisheries management. We demonstrate that biomass can be reconstructed from catch data whenever fishing mortality follows predictable dynamics over time (called 'effort dynamics'), and we develop a state-space catch only model (SSCOM) for this purpose. We use theoretical arguments and simulation modeling to demonstrate that SSCOM can, in some cases, estimate population status from catch data. Next, we use meta-analysis to estimate effort dynamics for US West Coast groundfishes before and after fisheries management changes in the mid-1990s. We apply the SSCOM using meta-analytic results to data for eight assessed species and compare results with stock assessment and data-poor methods. Results indicate general agreement among all three methods. We conclude that effort dynamics provides a theoretical basis for using catch data to reconstruct biomass and has potential for conducting data-poor assessments. However, we still recommend that index and compositional data be collected to allow application of data-rich methods. Si la recherche a demontre que l'etat des populations peut etre predit a l'aide de donnees sur les prises, les travaux justifiant la pertinence de ces predictions et leur adequation pour expliquer les changements dans la gestion des peches demeurent tres limites. Nous demontrons que la biomasse peut etre reconstituee a partir de donnees sur les prises quand la mortalite par peche suit une dynamique previsible dans le temps (appelee la'dynamique de l'effort') et, a cette fin, developpons un modele d'espace d'etats reposant uniquement sur les prises (SSCOM). Nous faisons appel a des arguments theoriques et la simulation pour demontrer que le SSCOM peut, dans certains cas, estimer l'etat de la population a partir de donnees sur les prises. Nous utilisons ensuite la metaanalyse pour estimer la dynamique de l'effort pour les poissons de fond de la cote Ouest americaine avant et apres des changements a la gestion des peches au milieu des annees 1990. Nous appliquons le SSCOM en utilisant les resultats de la metaanalyse a des donnees pour huit especes evaluees et comparons les resultats a des methodes d'evaluation des stocks et reposant sur des donnees limitees. Les resultats indiquent une bonne concordance, en general, des trois methodes. Nous en concluons que la dynamique de l'effort constitue une base theorique pour l'utilisation de donnees sur les prises dans le but de reconstituer la biomasse et pourrait etre utile pour des evaluations basees sur des donnees limitees. Nous recommandons toutefois que des donnees indicielles et compositionnelles soient recueillies pour permettre l'application de methodes axees sur des donnees abondantes. [Traduit par la Redaction], Introduction Marine fisheries globally have an enormous value in terms of food production, employment, and income for small- and large-scale fishers (Ye et al. 2012). However, the vast majority of [...]
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- 2013
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129. Estimating fine‐scale movement rates and habitat preferences using multiple data sources
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Thorson, James T., primary, Barbeaux, Steven J., additional, Goethel, Daniel R., additional, Kearney, Kelly A., additional, Laman, Edward A., additional, Nielsen, Julie K., additional, Siskey, Matthew R., additional, Siwicke, Kevin, additional, and Thompson, Grant G., additional
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- 2021
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130. Estimating spatiotemporal availability of transboundary fishes to fishery‐independent surveys
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O'Leary, Cecilia A., primary, Kotwicki, Stan, additional, Hoff, Gerald R., additional, Thorson, James T., additional, Kulik, Vladimir V., additional, Ianelli, James N., additional, Lauth, Robert R., additional, Nichol, Daniel G., additional, Conner, Jason, additional, and Punt, André E., additional
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- 2021
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131. Improving estimates of the state of global fisheries depends on better data
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Ovando, Daniel, primary, Hilborn, Ray, additional, Monnahan, Cole, additional, Rudd, Merrill, additional, Sharma, Rishi, additional, Thorson, James T., additional, Rousseau, Yannick, additional, and Ye, Yimin, additional
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- 2021
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132. Sense of Humor and Dimensions of Personality.
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Thorson, James A. and Powell, F. C.
- Abstract
Administered Multidimensional Sense of Humor Scale and Edwards Personal Preference Schedule to 426 adults, aged 18 through 90. Findings suggest that men create humor more, although women used more coping humor. As age increased, so did humor creativity, coping humor, and humor appreciation. Those who sought to create humor appeared to have need for dominance. (Author/NB)
- Published
- 1993
133. Geostatistical delta-generalized linear mixed models improve precision for estimated abundance indices for West Coast groundfishes
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Thorson, James T., Shelton, Andrew O., Ward, Eric J., and Skaug, Hans J.
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- 2015
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134. Mixed effects: a unifying framework for statistical modelling in fisheries biology
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Thorson, James T. and Minto, Cóilín
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- 2015
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135. Probability of stochastic depletion: an easily interpreted diagnostic for stock assessment modelling and fisheries management
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Thorson, James T., Jensen, Olaf P., and Hilborn, Ray
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- 2015
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136. To Laugh in the Face of Death: The Games That Lethal People Play.
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Thorson, James A. and Powell, F. C.
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A total of 399 individuals completed a lethal behaviors scale and a measure of death anxiety, which were found to have no significant correlation. Predictors of lethalness included doing dangerous things for the fun of it and having ever driven a motorcycle. The most lethal individuals were young, male, and less educated. (Author/ABL)
- Published
- 1990
137. The implications of spatially varying catchability on bottom trawl surveys of fish abundance: a proposed solution involving underwater vehicles
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Thorson, James T., Clarke, M. Elizabeth, Stewart, Ian J., and Punt, Andre E.
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Stock assessment (Wildlife management) -- Methods ,Fish populations -- Surveys ,Trawling -- Methods ,Striped bass -- Surveys ,Earth sciences - Abstract
Bottom trawl sampling is used to estimate trends in stock abundance for groundfishes worldwide, including Pacific rockfishes (Sebastes spp.). However, trawl sampling efficiency varies spatially and the distribution of groundfish populations may change among easy- and difficult-to-survey areas over time. These concerns have prompted interest in using underwater vehicles (UVs), for which catchability is likely to decrease less in rocky habitats. In this study, we use simulation modeling to evaluate the abundance trends arising from bottom trawl sampling given density-dependent habitat selection and spatially varying catchability. We first demonstrate that relative abundance indices in this case will generally be biased measures of changes in population abundance. We also propose and evaluate a sampling design that combines data from bottom trawl and UV gears. Combined sampling has greater precision than UV sampling, lower bias than bottom trawl sampling, and is robust to moderately violated assumptions regarding sampling strata or spatial catchability. We conclude by recommending future research that could test the assumptions under which combined sampling is a feasible solution to spatially varying catchability. L'echantillonnage au chalut de fond est utilise pour estimer les tendances d'abondance des stocks pour les poissons de fond a l'echelle mondiale, dontles sebastes du Pacifique (Sebastes spp.). L'efficacite de l'echantillonnage au chalut varie cependant dans l'espace et la repartition des populations de poissons de fond entre des regions faciles et difficiles a echantillonner peut varier dans le temps. Ces difficultes ont suscite un interet pour l'utilisation de vehicules sous-marins (UV), auxquels devrait etre associee une reduction moins importante de la capturabilite dans les habitats rocheux. Nous avons utilise la modelisation par simulation pour evaluer les tendances d'abondance decoulant de releves au chalut de fond etant donne une selection d'habitats dependant de la densite et une capturabilite variable dans l'espace. Nous demontrons d'abord que les indices d'abondance relative dans ce cas constituent generalement des mesures biaisees des variations de l'abondance de populations. Nous proposons et evaluons egalement une approche d'echantillonnage qui combine des donnees de chalut de fond et d'engins d'UV. L'echantillonnage combine offre une plus grande precision que l'echantillonnage par UV et un biais plus faible que l'echantillonnage au chalut de fond, en plus d'etre robuste en cas de non-respect modere des hypotheses de depart concernant les strates echantillonnees ou la variabilite spatiale de la capturabilite. Nous recommandons que soient menees des recherches visant a verifier les conditions dans lesquelles l'echantillonnage combine constitue une solution au probleme de la variabilite spatiale de la capturabilite., Introduction Information about trends in stock abundance for many groundfish species worldwide is obtained from surveys that are conducted using scientific sampling designs. Survey data are used in combination with [...]
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- 2013
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138. Grand challenge for habitat science: stage-structured responses, nonlocal drivers, and mechanistic associations among habitat variables affecting fishery productivity
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Thorson, James T, primary, Hermann, Albert J, additional, Siwicke, Kevin, additional, and Zimmermann, Mark, additional
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- 2021
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139. Modeling nearshore fish habitats using Alaska as a regional case study
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Grüss, Arnaud, primary, Pirtle, Jodi L., additional, Thorson, James T., additional, Lindeberg, Mandy R., additional, Neff, A. Darcie, additional, Lewis, Steve G., additional, and Essington, Timothy E., additional
- Published
- 2021
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140. Incorporating vertical distribution in index standardization accounts for spatiotemporal availability to acoustic and bottom trawl gear for semi-pelagic species
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Monnahan, Cole C, primary, Thorson, James T, additional, Kotwicki, Stan, additional, Lauffenburger, Nathan, additional, Ianelli, James N, additional, and Punt, Andre E, additional
- Published
- 2021
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141. Implementing two-dimensional autocorrelation in either survival or natural mortality improves a state-space assessment model for Southern New England-Mid Atlantic yellowtail flounder
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Stock, Brian C., primary, Xu, Haikun, additional, Miller, Timothy J., additional, Thorson, James T., additional, and Nye, Janet A., additional
- Published
- 2021
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142. Range edges of North American marine species are tracking temperature over decades
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Fredston, Alexa, primary, Pinsky, Malin, additional, Selden, Rebecca L., additional, Szuwalski, Cody, additional, Thorson, James T., additional, Gaines, Steven D., additional, and Halpern, Benjamin S., additional
- Published
- 2021
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143. Relative roles of natural and anthropogenic drivers of watershed invasibility in riverine ecosystems
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Lapointe, Nicolas W. R., Thorson, James T., and Angermeier, Paul L.
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- 2012
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144. Spawning biomass reference points for exploited marine fishes, incorporating taxonomic and body size information
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Thorson, James T., Cope, Jason M., Branch, Trevor A., and Jensen, Olaf P.
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Zoology -- Identification and classification ,Marine fishes -- Research ,Biomass -- Research ,Spawning -- Research ,Earth sciences - Abstract
Surplus production represents the processes that affect sustainable fishery harvest and is central to the ecology and management of marine fishes. Taxonomy and life history influence the ratio of spawning biomass at maximum sustainable yield to average unfished spawning biomass ([SB.sub.MSY]/[SB.sub.0]), and estimating this ratio for individual stocks is notoriously difficult. We use a database of published landings data and stock assessment biomass estimates and determine that process errors predominate in this data set by fitting a state-space model to data from each stock individually. We then fit multispecies process-error models while treating [SB.sub.MSY]/[SB.sub.0] as a random effect that varies by taxonomic order and maximum length. The estimated [SB.sub.MSY]/[SB.sub.0] = 0.40 for all 147 stocks is intermediate between the values assumed by the Fox and the Schaefer models, although Clupeiformes and Perciformes have lower and Gadiformes and Scorpaeniformes have higher [SB.sub.MSY]/[SB.sub.0] values. Model selection supports the hypothesis that large-bodied fishes for a given taxonomic order have relatively higher [SB.sub.MSY]/[SB.sub.0]. Results can be used to define reference points for data-poor fisheries or as input in emerging assessment methods. La production excedentaire represente les processus qui ont une incidence sur la recolte de poissons durable et est un element cle de l'ecologie et de la gestion des poissons marins. La taxonomie et le cycle biologique influencent le rapport entre la biomasse feconde correspondant au rendement maximum durable et la biomasse feconde non exploitee moyenne ([SB.sub.MSY]/[SB.sub.0]), l'estimation de ce rapport pour des stocks donnes etant particulierement difficile. Nous utilisons une base de donnees sur les debarquements publiees et des estimations de la biomasse reposant sur des evaluations des stocks et determinons, en ajustant un modele d'espace d'etats aux donnees pour chaque stock pris individuellement, que les erreurs de traitement dominent dans cette base de donnees. Nous ajustons ensuite des modeles multi-especes d'erreur de traitement en traitant le rapport [SB.sub.MSY]/[SB.sub.0] comme s'il s'agissait d'un effet aleatoire qui varie selon l'ordre taxonomique et la longueur maximum. La valeur de [SB.sub.MSY]/[SB.sub.0] = 0,40 estimee pour les 147 stocks est intermediaire entre les valeurs implicites dans les modeles de Fox et de Schaefer, bien que les [SB.sub.MSY]/[SB.sub.0] des Clupeiformes et les Perciformes soient plus faibles et ceux des Gadiformes et des Scorpaeniformes, plus grands. La selection de modele appuie l'hypothese voulant que les poissons a grands corps d' un ordre taxonomique donne presentent un [SB.sub.MSY]/[SB.sub.0] relativement plus eleve. Ces resultats peuvent servir a definir des points de reference pour les peches pour lesquelles peu de donnees sont disponibles ou comme intrants pour de nouvelles methodes d' evaluation. [Traduit par la Redaction], Introduction Surplus production (i.e., production of biomass above what is needed to replace individuals lost to natural mortality) incorporates the combined effects of individual growth, recruitment, predation, and disease (Hilborn [...]
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- 2012
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145. Linking fishing mortality reference points to life history traits: an empirical study
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Zhou, Shijie, Yin, Shaowu, Thorson, James T., Smith, Anthony D.M., and Fuller, Michael
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Fish stocking -- Methods ,Stock assessment (Wildlife management) -- Methods ,Earth sciences - Abstract
The rule of thumb that fishing mortality to achieve maximum sustainable yield ([F.sub.MSY]) equals natural mortality (M) has been both criticised and supported by theoretical arguments. However, the relationship has been rarely investigated using empirical data. We carried out a meta-analysis on 245 fish species worldwide and linked three types of reference points ([F.sub.BRP]: [F.sub.MSY], [F.sub.proxy], and [F.sup.0.5r]) to M and other life history parameters (LHP). We used Bayesian hierarchical errors-invariables models to investigate the relationships and included the effect of taxonomic class and order. We compared various models and found that natural mortality is the most important LHP affecting [F.sub.BRP]. Other covariates, such as von Bertalanffy growth coefficient, asymptotic length, maximum age, and habitat types, add little to the relationship, partially because of correlation and large measurement and process errors. The best model results in [F.sub.MSY] = 0.87 M (standard deviation (SD) = 0.05) for teleosts and [F.sub.MSY] = 0.41 M (SD = 0.09) for chondrichthyans. [F.sub.proxy] based on per-recruit analysis is about 15% smaller than [F.sub.MSY]. Results could be used to estimate [F.sub.BRP] from LHP in data-poor situations. Des arguments theoriques ont ete utilises tant pour critiquer que pour appuyer la regle generalement evoquee voulant que la mortalite du poisson necessaire a l'atteinte du rendement equilibre maximum ([F.sub.MSY]) soit egale a la mortalite naturelle (Mi). Cependant, cette relation a rarement ete examinee a la lumiere de donnees empiriques. Nous avons effectue une meta-analyse de 245 especes de poissons a l'echelle planetaire et relie trois types de points de reference ([F.sub.BRP] : [F.sub.MSY], [F.sub.proxy], et Fx5r)a M ainsi qu'ad'autres parametres du cycle biologique (LHP). Nous avons utilise des modeles hierarchiques bayesiens d' erreurs sur les variables pour etudier ces relations et y avons integre l' effet de la classe et de l'ordre taxinomiques. Nous avons compare divers modeles et determine que la mortalite naturelle est le LHP ayant la plus grande incidence sur les [F.sub.BRP]. D'autres covariables, telles que le coefficient de croissance de von Bertalanffy, la longueur asymptotique, l'age maximum et les types d'habitat, n'ont que peu d'incidence sur la relation, en raison notamment de la correlation et d'importantes erreurs de mesure et de traitement. Le meilleur modele donne une valeur de [F.sub.MSY] = 0,87 M (ecart-type (SD) = 0,05) pour les teleosteens et de [F.sub.MSY] = 0,41 M (SD = 0,09) pour les chondrichthyens. La valeur de [F.sub.proxy] basee sur l'analyse du rendement par recrue est d'environ 15 % inferieure a [F.sub.MSY]. Les resultats pourraient etre utilises pour l'estimation de [F.sub.BRP] a partir de LHP dans les cas ou peu de donnees sont disponibles. [Traduit par la Redaction], Introduction Biological reference points (BRPs) are used both as targets and limits in stock status assessment, harvest control rules, and tactical fisheries management. Generally, BRPs may be based either on [...]
- Published
- 2012
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146. Using model-based inference to evaluate global fisheries status from landings, location, and life history data
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Thorson, James T., Branch, Trevor A., and Jensen, Olaf P.
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Fisheries -- Environmental aspects ,Fish industry -- Environmental aspects ,Environmental impact analysis -- Research ,Earth sciences - Abstract
Assessing fishery collapses worldwide is hindered by the lack of biomass data for most stocks, leading to the use of landings-based proxies or the assumption that existing stock assessments are globally representative. We argue that the use of sparse assessments to evaluate fishery status requires model-based inference because assessment availability varies spatially and temporally, and we derive a model that extrapolates from assessment results to available landings, life history, and location data. This model uses logistic regression to classify stocks into different prediction bins and estimates the probability of collapse in each using cross-validation. Results show that landings, life history, and location are informative to discriminate among different probabilities of collapse. We find little evidence that regions with fewer assessments have a greater proportion of collapsed stocks, while acknowledging weak inferential support regarding regions with one or fewer assessments. Our extrapolation suggests that 4.5%-6.5% of stocks defined by landings data are collapsed, but that this proportion is increasing. Finally, we propose a research agenda that combines stock assessment and landings databases while overcoming limitations in each. Le manque de donnees sur la biomasse pour la plupart des stocks limite l'evaluation de l'effondrement des peches a l'echelle mondiale, de sorte qu'il est necessaire d'utiliser des donnees de substitution reposant sur les debarquements ou encore de presumer que les evaluations des stocks existantes sont representatives de la situation a l'echelle planetaire. Dans le present article, il est postule que l'utilisation d'un nombre limite d'evaluations pour evaluer l'etat des peches necessite le recours a l'inference basee sur un modele puisque la disponibilite des evaluations varie dans l'espace et dans le temps. Un modele est en outre etabli qui extrapole des resultats d'evaluation aux donnees disponibles sur les debarquements, le cycle de vie et l'emplacement. Ce modele fait appel a la regression logistique pour classer les stocks selon differents compartiments de prediction et estime la probabilite de l'effondrement de chaque stock a l'aide de la validation croisee. Les resultats montrent que les debarquements, le cycle de vie et l'emplacement constituent des renseignements utiles pour discriminer entre differentes probabilites d'effondrement. Peu de donnees probantes appuient la these voulant que les regions pour lesquelles moins d'evaluations sont disponibles aient une plus grande proportion de stocks effondres, bien qu'il convienne de souligner la faiblesse du support inferentiel pour les regions pour lesquelles une seule evaluation ou moins est disponible. L'extrapolation suggere que de 4,5 % a 6,5 % des stocks definis par les donnees sur les debarquements sont effondres et que cette proportion est en hausse. Enfin, un programme de recherche est propose qui combine l'utilisation de bases de donnees sur l'evaluation des stocks et sur les debarquements afin de contourner les problemes inherents a chacun de ces outils. [Traduit par la Redaction], Introduction There is substantial debate over whether fisheries management has failed, both in scientific journals and popular media (Pauly 2009; Greenberg 2010; Hilborn 2011). This debate has practical importance, because [...]
- Published
- 2012
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147. Accounting for fish shoals in single- and multispecies survey data using mixture distribution models
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Thorson, James T., Stewart, Ian J., and Punt, Andre E.
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Fish populations -- Distribution -- Environmental aspects ,Trawling -- Methods ,Fishery management -- Research ,Striped bass -- Distribution -- Environmental aspects ,Company distribution practices ,Earth sciences - Abstract
A scientific bottom trawl survey targeting Pacific rockfishes (Sebastes spp.) occasionally yields extraordinary catch events (ECEs) in which catch-per-unit-area is much greater than usual. We hypothesize that ECEs result from trawl catches of fish shoals. We developed mixture distribution models for positive catch rates to identify spatial covariates associated with ECEs or normal trawl catches and used simulation modeling to contrast the performance of mixture distribution and conventional log-linear models for estimating an annual index of positive catch rates. Finally, mixed-effects modeling was applied to multispecies data to evaluate the hypothesis that ECEs are related to shoaling behaviors. Results show that mixture distribution models are often selected over conventional models for shoaling species and that untrawlable habitat has a positive effect on rockfish densities. Simulation shows that mixture distribution models can perform as well as or better than conventional models at predicting positive catch rates. Finally, model selection supports the hypothesis that shoaling behaviors contribute to the occurrence of ECEs. We propose that greater understanding of ECEs and shoaling habitat selection could be useful in future spatial management and survey design and that mixture distribution models could improve methods for estimating annual indices of abundance. Un inventaire scientifique au chalut de fond qui cible les sebastes du Pacifique (Sebastes spp.) produit a l'occasion un evenement de capture exceptionnel (ECE) dans lequel les captures par unite d'effort sont beaucoup plus importantes que d'habitude. Nous emettons comme hypothese que ces ECE resultent de la capture de bancs de poissons. Nous avons mis au point des modeles de melanges de distributions pour les taux de captures positifs afin d'identifier les covariables spatiales associees aux ECE et aux captures normales au chalut; nous avons aussi utilise des modeles de simulation pour comparer les performances des modeles de melanges de distributions et les modeles log-lineaires conventionnels pour l'estimation d'un indice annuel de taux de captures positifs. Finalement, une modelisation d'effets mixtes avec les donnees multispecifiques a permis d'evaluer l'hypothese selon laquelle les ECE sont relies aux comportements de formation de bancs. Les resultats montrent que les modeles de melanges de distributions sont souvent choisis de preference aux modeles conventionnels pour les especes qui forment des bancs et ils indiquent que l'habitat dans lequel on ne peut faire du chalutage a un effet positif sur les densites de sebastes. Les simulations montrent que les modeles de melanges de distribution peuvent performer aussi bien ou mieux que les modeles conventionnels pour predire les taux de captures positifs. Enfin, la selection des modeles appuie l'hypothese qui veut que les comportements de formation des bancs contribuent a l'avenement des ECE. Nous croyons qu'une meilleure comprehension des ECE et de la selection des habitats pour la formation des bancs pourrait s'averer utile dans le futur pour la gestion spatiale et la planification des inventaires; les modeles de melanges de distributions pourraient ameliorer les methodes d'estimation des indices annuels d'abondance. [Traduit par la Redaction], Introduction Fishery-independent bottom trawl surveys conducted by the National Marine Fisheries Service Northwest Fisheries Science Center (NMFS-NWFSC) are an important data source for groundfishes off the US west coast. Data [...]
- Published
- 2011
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148. Multispecies estimation of Bayesian priors for catchability trends and density dependence in the US Gulf of Mexico
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Thorson, James T. and Berkson, Jim
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Bayesian statistical decision theory -- Usage -- Methods -- Research ,Fisheries -- Research -- Usage -- Methods ,Fish industry -- Research -- Usage -- Methods - Abstract
Fishery-dependent catch-per-unit-effort (CPUE) derived indices of stock abundance are commonly used in fishery stock assessment models and may be significantly biased due to changes in catchability over time. Factors causing time-varying catchability include density-dependent habitat selection and technology improvements such as global positioning systems. In this study, we develop a novel multispecies method to estimate Bayesian priors for catchability functional parameters. This method uses the deviance information criterion to select a parsimonious functional model for catchability among 10 hierarchical and measurement error models. The parsimonious model is then applied to multispecies data, while excluding one species at a time, to develop Bayesian priors that can be used for each excluded species. We use this method to estimate catchability trends and density dependence for seven stocks and four gears in the Gulf of Mexico by comparing CPUE-derived index data with abundance estimates from virtual population analysis calibrated with fishery-independent indices. Catchability density dependence estimates mean that CPUE indices are hyperstable, implying that stock rebuilding in the Gulf may be progressing faster than previously estimated. This method for estimating Bayesian priors can provide a parsimonious method to compensate for time-varying catchability and uses multispecies fishery data in a novel manner. Resume: Les indices d'abondance des stocks derives des captures par unite d'effort (CPUE) basees sur le type de peche sont couramment utilises dans les modeles d'evaluation des stocks de peche, mais ils peuvent etre fausses de facon significative a cause des changements de capturabilite dans le temps. Les facteurs qui expliquent la variation temporelle de la capturabilite incluent la selection d'habitat en fonction de la densite et les avances technologiques, telles que les systemes de positionnement global. Nous mettons au point, dans notre etude, une methode plurispecifique inedite pour estimer les a priori bayesiens pour les parametres fonctionnels de capturabilite. La methode utilise le critere d'information de la deviance afin de choisir un modele fonctionnel parcimonieux de capturabilite parmi dix modeles hierarchiques et modeles de mesures d'erreurs. Le modele parcimonieux est alors applique aux donnees plurispecifiques, en excluant une espece a la fois, afin d'obtenir des a priori bayesiens a utiliser pour chacune des especes exclues. Nous utilisons la methode pour estimer les tendances de capturabilite et la densite-dependance pour sept stocks et quatre engins de peche dans le golfe du Mexique en comparant les donnees des indices derives des CPUE aux estimations d'abondance d'une analyse de population virtuelle calibree avec des indices independants des peches. Les estimations de la densite dependance de la capturabilite signifient que les indices CPUE sont hyperstables, ce qui implique que la reconstruction des stocks dans le golfe progresse peut-etre plus rapidement qu'on ne le croyait anterieurement. Notre methode pour l'estimation des a priori bayesiens fournit un mecanisme parcimonieux pour compenser la variabilite temporelle de la capturabilite et utilise les donnees de peches plurispecifiques de maniere inedite. [Traduit par la Redaction], Introduction Fishery-dependent indices of stock abundance, derived from catch-per-unit-effort (CPUE) data, are often used in stock assessment models by scaling CPUE to abundance using the catchability coefficient [[^.I].sub.t] = q[summation [...]
- Published
- 2010
149. Standardizing compositional data for stock assessment
- Author
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Thorson, James T.
- Published
- 2014
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150. Corrigendum to “Perspective: Let’s simplify stock assessment by replacing tuning algorithms with statistics” [Fish. Res. 219 (2019) 133–139]
- Author
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Thorson, James T., primary
- Published
- 2021
- Full Text
- View/download PDF
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