%0 Conference Proceedings
%9 ACTI : Communications avec actes dans un congrès international
%A Fonteneau, Alain
%T On the movements and stock structure of skipjack (Katsuwonus pelamis) in the Indian ocean
%S 16ème groupe de travail sur les thons tropicaux
%C Victoria
%D 2014
%L fdi:010063396
%G ENG
%I CTOI
%K PECHE THONIERE ; ESTIMATION DE STOCK ; CAPTURE ; MARQUAGE ; DISTRIBUTION SPATIALE ; VARIATION SAISONNIERE ; VARIATION PLURIANNUELLE
%K OCEAN INDIEN ; TANZANIE ; SEYCHELLES
%N IOTC-2014-WPTT16-24
%P 16
%U https://www.documentation.ird.fr/hor/fdi:010063396
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers15-03/010063396.pdf
%W Horizon (IRD)
%X This paper discusses the skipjack movements observed in the Indian Ocean based on an analysis of fishery data of the 13.128 selected recoveries of tagged skipjack. Its goal is to evaluate the potential geographical heterogeneity of the skipjack population fished in the Indian Ocean. Significant latitudinal & longitudinal movements have been frequently observed; the geographical range of skipjack movements appears to be wide in scale, showing an average distance over 1000 miles between tagging & recovery positions. These distances are showing an increasing trend with time at liberty, and reaching average distances of 1400 miles after 2 years. Recovery data are also showing that skipjack movements are often very fast, for instance reaching average distances over 800 miles after only 1 month at liberty in the Tanzania tagging. Distances covered are the lowest for skipjack tagged in the Maldives and in Seychelles islands and much larger in the Tanzania and Seychelles tagging. these differences are discussed. Because of these fast and extensive movements of skipjack, it can be concluded that its population is highly mobile in the Indian Ocean, but that the mixing rates of individual skipjack that are fished in remote parts of the Indian Ocean are probably low or very low. Based on these results, it is proposed that skipjack indicators and future skipjack stock assessment should be stratified on at least 4 areas, and estimating the mixing rates of skipjack tunas fished in each of these areas.
%B GTTT : Groupe de Travail sur les Thons Tropicaux
%8 2014/11/15-19
%$ 040PECHE03 ; 036MILMAR