Scientific estimates of bycatch landed by the Spanish surface longline fleet targeting swordfish (Xiphias gladius) in the Indian Ocean with special reference to the 2004 ¿ 2006 period

Abstract

This paper presents scientific estimates of the bycatch species landed by the Spanish surface longline fleet targeting swordfish (Xiphias gladius) in the Indian Ocean since the beginning of this fishery in 1993, as well as an update for the recent period 2004- 2006. The species classified as bycatch amounted to 46.2% of the total weight landed. The three most prevalent species in the catch, Xiphias gladius, Prionace glauca and Isurus oxyrhinchus, represented 85.2% of the total weight landed during this last period. As far as bycatch species are concerned, large pelagic sharks were the most prevalent group with 76.5% of the bycatch in weight, whereas tunas amounted to 15.0%, billfish to 2.2% and other species to 6.3%. Prionace glauca and Isurus oxyrhinchus are the two most prevalent bycatch species in the group of large pelagic sharks, reaching 84.4% and 12.0% of the landings of this group, respectively.