Cath analysis of tunas and related species base don the pole and trolling fishing of the RV Malacostraca of 1980 the 1991

Abstract

This work presents the analysis of the pole-and-line and trolling catches conducted during several research cruises on board of RV Malacostraca from 1980 to 1991, off southern and southeastern Brazilian coast, between 18°S and 26°S. The captures of skipjack, Katsuwonus pelamis, represented 94.01% of the total catches, followed by yellowfin-tuna, Thunnus albacares, and dolphin-fish, Coryphaena hippurus. Other species caught were wahoo (Acanthocybium solandri), frigate tuna (Auxis thazardi), jacks (Caranx spp.), little tunny (Euthynnus alletteratus), yellowtail (Seriola lalandi), barracuda (Sphyraena spp.), blackfin tuna (Thunnus atlanticus) and bigeye tuna (Thunnus obesus). Biometric relations of the main species are presented. The catch per unit of effort (CPUE) for K. pelamis varied with latitude, year and depth. The variation associated to latitude and depth is probably associated to the Tropical Water of the Brazilian Current and to Coastal Water dynamics. The length composition analysis of the catches of K. pelamis showed that small specimens are present around Trindade and Martin-Vaz Isles suggesting that during its development this species migrates southward to areas near the continental shelf break.