Semi-pelagic Longline and Trammel Net Elasmobranch Catches in Southern Portugal: Catch Composition, Catch Rates and Discards

Rui Coelho, Karim Erzini, Luís Bentes, Carla Correia, Pedro G. Lino, Pedro Monteiro,
Joaquim Ribeiro, and Jorge M. S. Gonçalves

Universidade do Algarve, CCMAR/FCMA, Campus de Gambelas, 8000 Faro, Portugal

Abstract

In Portugal, elasmobranch landings have decreased substantially in recent years. In this work, elasmobranch catches in semi-pelagic longlines (1997 and 1998) were compared with those in trammel nets (2000) in the Algarve, southern Portugal areas. In the semi-pelagic longline fishery, 7 elasmobranch species represented 33.4% (2 185 specimens) of the total fish catches. Among the elasmobranch species, the most abundant were Galeus melastomus (63.3%), Etmopterus pusillus (21.7%) and Scyliorhinus canicula (14.2%). Most of these elasmobranchs were discarded (68.3% in total). In the trammel net fishery, 16 different elasmobranch species represented 4.3% (597 specimens) of total fish catches and the most important species were Raja undulata (43.6%) and S. canicula (10.2%). The majority of the elasmobranchs caught in trammel nets had commercial value, and only 5.4% were discarded. In both fisheries, intra-specific catch rates varied with depth. Length-frequency distributions for the only species with relatively high catches in both fisheries, S. canicula, showed that, in general, trammel nets catch larger specimens and in a narrower length range than do longlines.

Key words: catch composition, catch rate, discard, longline, Portugal, trammel net

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