Prey composition in stomachs of Black-browed Albatross and White-chinned petrels incidentally hooked in the Argentine longline fishery.

GANDINI, P., COPELLO, S., FRERE, E. & QUINTANA, F.

Montevideo, Uruguay

Congreso; Albatross Conference; 2004

Prey composition in stomachs of Black-browed Albatross and White-chinned petrels incidentally hooked in the Argentine longline fishery Gandini, P(1)., Copello, S. (2), Frere, E.(1) and Quintana, F. (2) (1) Centro de Investigaciones de Puerto Deseado (UNPA), CONICET and Wildlife Conservation Society. Avda. Prefectura s/n (9050), Puerto Deseado, Santa Cruz, Argentina. (2) Centro Nacional Patagonico, CENPAT, Puerto Madryn, Argentina. The stomach contents of Black-browed albatross (BBA) and White-chinned petrels (WCP) incidentally caught in longline hooks were analyzed. Birds were caught between September 2000 to December 2003, frozen at –20 °C and dissected at laboratory. The fish components of the diet were identified from the presence of otoliths and bones using keys and our own collection as well as Cephalopod beaks. When possible, otoliths ‘ length and width for fishes and lower rostral length of cephalopod beaks was measured to estimate mass. Fish were present in 45% of the stomachs (N = 101) with a total of 6 species identified (Merluccius hubbsi, Macruronus magellanicus, Genypterus blacodes, Salilota australis, Helicolenus lahillei, and Sprattus fuegensis), Cephalopods were presents in 77% of the stomachs with four species (Mototeuthis sp. Illex sp., Loligo gahi. and Gonathus antarticus), 16% of crustacean (3 Orders) and 3% had garbage in the BBA stomachs. For the WCP, Cephalopods were present in 99 % of the stomachs (N = 73) with four species identified (Illex sp, Kondakovia sp., Loligo gahi, and Gonatus sp), while fish was present in 36% of the stomachs with 6 species identified (Argentine hake, Kingclip, blackbelly rosefish, hoki, Raneya brasiliensis and Tachurus lathami), two Orders of crustaceans with a frequency of 3% and other items as garbage and stones being present in 11% and 7% of the stomachs respectively. Stomach contents in both bird species showed the high risk they are exposed to incidental capture being a high proportion of the identified preys target, bait or by-catch species for this fishery.