Bycatch of sharks (Elasmobranchii) in the Patagonian red shrimp Pleoticus muelleri (Bate, 1888) fishery

PAULA V. CEDROLA; GONZÁLEZ, ALBERTO M.; CHIARAMONTE, GUSTAVO ENRIQUE; ALEJANDRO D. PETTOVELLO

Revista del Museo Argentino de Ciencias Naturales, n.s.

Museo Argentino de Ciencias Naturales

Lugar: Buenos Aires; Año: 2012 vol. 14 p. 349 - 356

1514-5158

The double?beam trawl fishery for the Patagonian red shrimp (Pleoticus muelleri) is the main crustaceanfishery of the Southwestern Atlantic Ocean. The shark bycatch in 723 tows of this fishery was surveyed fromApril 2003 to October 2003. Six species of sharks were recorded: Squalus acanthias (n=321); Squalus mitsukurii(n=1); Squatina sp. (n=1); Schroederichthys bivius (n=327); Galeorhinus galeus (n=4) and Mustelus schmitti(n=13). Length-frequency structure, sex composition, spatial distribution and estimation of density and bycatchper unit of effort are given for the main species. The bycatch of sharks in this fishery was estimated in ~61 mt/year, equivalent to 0.15% of the shrimp total capture in 2003. S. acanthias contributed with 30.5 mt (50.15%)whilst S. bivius contributed with 22.6 mt (37.2%). Whereas the abundance for S. acanthias in Patagonian watersincreased by three fold between 1997 and 2001, the abundance of S. bivius in the same period have decreasedin the same amount. In addition, losses of important reproductive sites in southern Patagonia for S. bivius weredetected. These issues together with the results presented herein add the Patagonian red shrimp fishery to thepotential threats S. bivius is exposed to.