Incidental catch associated with swordfish longline fisheries in the south-west Atlantic Ocean

This paper describes the composition of the harvest by species of two vesse ls operating with two different pelagic longline systems aimed at swordfish (Xiphias gladius). Four zones were surveyed in the Uruguayan EEZ and inter national waters in the south-western Atlantic. Data were collected by obser vers on board who recorded the number of individuals in each of the species caught. In all, 50 species were caught, of which 15 were cartilaginous fis h, 27 were teleosts and eight were 'non-fish' species (birds, mammals and t urtles). The most abundant species were blue shark (Prionace glauca) (43%), swordfish (27%) and albacore tuna (Thunnus alalunga) (9%). The abundances of blue shark and of swordfish differed significantly between the two riggi ng systems and among the four zones. The catch was classified into three ma rketing groups: primary marketing (swordfish and high-price tuna), secondar y marketing (non-target species but marketable) and discards (with no comme rcial value). In terms of numbers, the first two groups represented between 91% and 72% of the species collected. This percentage may vary if the catc h is analysed by weight, as only part of the carcass and shark fms are used .