INVESTIGADORES
FAVERO Marco
artículos
Título:
Trophic relationships between the Kelp Gull and the Antarctic Limpet at King George Island, South Shetland Islands, Antarctica
Autor/es:
FAVERO M, MP SILVA & G FERREYRA
Revista:
POLAR BIOLOGY
Referencias:
Año: 1997 vol. 17 p. 431 - 436
ISSN:
0722-4060
Resumen:
The diet of the kelp gull (Larus dominicanus), its foraging behaviour and the consumption rates on the Antarctic limpet (Nacella concinna) were studied during austral spring and summer 1992/1993 and  1993/1994 at Potter Peninsula, King George Island, Antarctica. Prey information was obtained by collecting 237 pellets, foraging behaviour was observed by focal and instantaneous scan samplings, and consumption rate was estimated by means of weekly sampling of limpets found in 5 nests and their respective middens. Limpets were the most important prey followed by scavenged prey (penguin and seal carcasses), amphipods, snails, ®sh and euphausiids. Foraging gulls spent 51% of the time searching for limpets, 10% moving between foraging areas, 9% in catching effort and 15% handling prey. The  number of gulls observed searching for limpets was inverselycorrelated with the tidal height. In the diet limpets provide 102.3, 159.4 and 188.1 kJ gull)1 day)1 during incubation, hatching and brooding respectively; these values range between 15 and 27%, with a maximum of 40%, of the basic daily energy requirements of kelp gulls. Total consumption rate estimations for the whole population of gulls at Potter Peninsula reached between 3400 and 4800 limpets day)1, which represents approximately 10±14% of the total annual limpet mortality.Larus dominicanus), its foraging behaviour and the consumption rates on the Antarctic limpet (Nacella concinna) were studied during austral spring and summer 1992/1993 and  1993/1994 at Potter Peninsula, King George Island, Antarctica. Prey information was obtained by collecting 237 pellets, foraging behaviour was observed by focal and instantaneous scan samplings, and consumption rate was estimated by means of weekly sampling of limpets found in 5 nests and their respective middens. Limpets were the most important prey followed by scavenged prey (penguin and seal carcasses), amphipods, snails, ®sh and euphausiids. Foraging gulls spent 51% of the time searching for limpets, 10% moving between foraging areas, 9% in catching effort and 15% handling prey. The  number of gulls observed searching for limpets was inverselycorrelated with the tidal height. In the diet limpets provide 102.3, 159.4 and 188.1 kJ gull)1 day)1 during incubation, hatching and brooding respectively; these values range between 15 and 27%, with a maximum of 40%, of the basic daily energy requirements of kelp gulls. Total consumption rate estimations for the whole population of gulls at Potter Peninsula reached between 3400 and 4800 limpets day)1, which represents approximately 10±14% of the total annual limpet mortality.