Estimation of the relative annual abundance of yellowfin tuna, Thunnus albacares, in the Eastern Pacific Ocean during 1970-1985

Punsly, Richard G. (1987) Estimation of the relative annual abundance of yellowfin tuna, Thunnus albacares, in the Eastern Pacific Ocean during 1970-1985. Inter-American Tropical Tuna Commission Bulletin, 19(3), pp. 263-306.

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Abstract

ENGLISH: Estimates of relative annual abundance of yellowfin tuna in the eastern Pacific Ocean during 1970-1985 are made using catch rates, measured as tons caught by purse seiners per hour of searching. Catch rates are standardized a weighted generalized linear model. The important standardizing factors are vessel speed, season-area, and whether the yellowfin were caught in association with dolphins, skipjack tuna, or floating objects. Observations are weighted to give equal areas equal weight and to give each unit of fishing effort equal weight within an area. The results indicate that catch per days fishing underestimates abundance during the late 1970's when the fishery shifted some of its effort from dolphin sets to floating object sets, and overestimates abundance when the fishery shifted back to dolphin sets in 1984 and 1985. SPANISH: Se estima la abundancia anual relativa del atún aleta amarilla en el Océano Pacífico oriental (OPO) durante 1970-1985 por medio de tasas de captura, calculadas como toneladas cortas capturadas por barcos cerqueros por hora de búsqueda. Se usa un modelo lineal ponderado generalizado para estandardizar las tasas de captura. Los factores importantes de estandardización son la velocidad del barco, temporada-área, y si se capturaron los aletas amarillas en asociación con delfines, barriletes, o objetos flotantes. Se ponderaron las observaciones para otorgar igual importancia a áreas iguales y a cada unidad de esfuerzo pesquero dentro de un área. Los resultados señalan que la captura por día de pesca estima por bajo la abundancia durante los últimos años de la década de los 70, en cual época la pesquería trasladó parte de su esfuerzo de lances sobre delfines a lances sobre objetos flotantes, y la sobreestima al volver la pesquería a lances sobre delfines en 1984 y 1985. (PDF contains 45 pages.)

Item Type: Article
Title: Estimation of the relative annual abundance of yellowfin tuna, Thunnus albacares, in the Eastern Pacific Ocean during 1970-1985
Personal Creator/Author:
CreatorsEmail
Punsly, Richard G.
Journal or Publication Title: Inter-American Tropical Tuna Commission Bulletin
Volume: 19
Number: 3
Page Range: pp. 263-306
Date: 1987
Issuing Agency: Inter-American Tropical Tuna Commission
Additional Information: This article is bilingual and contains both Spanish and English translations.
Uncontrolled Keywords: annual abundance; yellowfin tuna; Thunnus albacares; Eastern Pacific Ocean; abundancia anual; atún aleta amarilla; Thunnus albacares; Océano Pacifico Oriental
Subjects: Fisheries
Item ID: 3481
Depositing User: Joan Parker
Date Deposited: 02 Jun 2010 04:24
Last Modified: 29 Sep 2011 17:20
URI: http://aquaticcommons.org/id/eprint/3481

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