Status of swordfish stocks in the eastern Pacific Ocean estimated using data from Japanese tuna longline fisheries

Abstract

Swordfish (Xiphias gladius) are harvested in target and non-target fisheries throughout the eastern Pacific Ocean (east of 150°W). Analyses of trends in catch rates (catch per unit effort) standardized using general linear models indicate that there are two stocks in the eastern Pacific Ocean that have a north–south boundary at 5°S latitude; this is in striking contrast to the 10°N boundary that has generally been assumed by previous studies. Trends in standardized catch per unit effort have held relatively level for the north stock and have been increasing for the south stock. Considering these trends and given that annual catches have been fairly stable in the region since 1989, it appears that swordfish are not overfished in the eastern Pacific Ocean. Given the potential for rapid change in the nature of those gill-net and longline fisheries that are increasingly targeting swordfish in the region, the trends in standardized catch per unit effort should be closely monitored for indications of changing status of these stocks.