SCIENTIFIC ESTIMATIONS OF BYCATCH LANDED BY THE SPANISH SURFACE LONGLINE FLEET TARGETING SWORDFISH (Xiphias gladius) IN THE ATLANTIC OCEAN WITH SPECIAL REFERENCE TO THE YEARS 2005 AND 2006 .

This document provides an overview of the bycatch levels by species landed by the Spanish surface longline fleet targeting swordfish (Xiphias gladius) in the Atlantic Ocean and Mediterranean Sea from 1997 to 2004. This information has also been updated for the years 2005 and 2006, the most recent data available. The three most prevalent species in the catch, Xiphias gladius, Prionace glauca and Isurus oxyrhinchus represented, on average 94.2% and 96.1% of the total Atlantic and Mediterranean landings in weight during the last two years, respectively. During the years 2005-2006 the species assumed to be bycatch accounted for 71.7% of the total landings in weight from the Atlantic areas –large pelagic sharks, 67.4; tunas, 2.2 %; billfish,1.2% and other species, 0.9%–. In the Mediterranean Sea, the reported bycatch amounted to around 7.0% of the total landings in weight –large pelagic sharks,4.6%; tunas, 1.6%; other species, 1.3% and billfish close to 0%. As far as bycatch species are concerned, large pelagic sharks were the most prevalent, comprising an average of 94.0% of the bycatch in weight, whereas tunas accounted for 3.1%; billfish,1.7% and other species, 1.2% in the Atlantic. In the Mediterranean, large pelagic sharks amounted to 51.8%, tunas, 23.0; other species,25.2% and billfish,0.1%.. Prionace glauca and Isurus oxyrhinchus were the most important species within the group of large pelagic sharks, reaching prevalences of 88.2% and 9.5%, respectively in the Atlantic –very similar to levels observed in other oceans–. The prevalences of these species within the group of large pelagic sharks in the Mediterranean sea were 77.3% and 6.0% , respectively.