Exchange rates of yellowfin and bigeye tunas and fishery interaction between Cross seamount and near-shore FADs in Hawaii

¹ Pelagic Fisheries Research Program, Joint Institute of Marine and Atmospheric Research, University of Hawaii, Honolulu, USA
² Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, USA

Received: 27 March 2000
Accepted: 28 March 2000

Abstract

Yellowfin and bigeye tunas (Thunnus albacores and Thunnus obesus) were tagged and released between August 1995 and December 1997 at Cross Seamount and NOAA weather buoys about 200 Nmi south of Honolulu. The release and recapture data were stratified into five sites, and a bulk transfer model was used to estimate natural mortality, fishing mortality and transfer rates between the five sites. Bigeye are much more persistent at Cross seamount and less vulnerable to the fishery than yellowfin. Fishing accounts for about 5 % of the total mortality of both bigeye and yellowfin at Cross Seamount. Yellowfin are a major component of catches at inshore FADs in Hawaii. The rate of immigration from Cross Seamount to the inshore FADs is very low for both species. The fishing mortality at Cross seamount is substantial but is not adversely impacting the populations either at Cross or the inshore FADs.