Different residence times of yellowfin tuna, Thunnus albacares, and bigeye tuna, T. obesus, found in mixed aggregations over a seamount

Abstract

Aggregations of tuna can be found in association with seamounts throughout all the tropical oceans and these aggregations are often exploited by tuna fishing fleets (Fonteneau, 1991). In Hawaii, a fishery has developed over the last decade that targets the mixed species aggregations of predominantly subadult tuna found in association with the Cross Seamount located approximately 160 nmi south of Honolulu and Oahu and 150 miles east of South Point on the island of Hawaii (Fig. 1). Its shallowest depth is about 330 meters. The Cross Seamount fishery is a hybrid troll, jig, and handline fishery that augments slow trolling methods by using frozen, cut and whole bait to induce feeding behavior around the fishing boat. Initially described as a yellowfin tuna (Thunnus albacares) fishery, closer scrutiny has revealed that the catch is dominated by juvenile bigeye tuna (T. obesus). Schools of skipjack tuna (Katsuwonus pelamis) are also found over the seamount but these Different residence times of yellowfin tuna, Thunnus albacares, and bigeye tuna, T. obesus, found in mixed aggregations over a seamount