TROPHIC RELATIONSHIPS BETWEEN THE KELP GULL AND THE ANTARCTIC LIMPET AT KING-GEORGE-ISLAND (SOUTH SHETLAND ISLANDS, ANTARCTICA) DURING THE BREEDING-SEASON

The diet of the kelp gull (Larus dominicanus), its foraging behaviour and the consumption rates on the Antarctic limpet (Nacella concinna) w ere studied during austral spring and summer 1992/1993 and 1993/1994 a t Potter Peninsula, King George Island, Antarctica. Prey information w as obtained by collecting 237 pellets, foraging behaviour was observed by focal and instantaneous scan samplings, and consumption rate was e stimated by means of weekly sampling of limpets found in 5 nests and t heir respective middens. Limpets were the most important prey followed by scavenged prey (penguin and seal carcasses), amphipods, snails, fi 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 inversely correlated with the tidal height. In the diet limpets p rovide 102.3, 159.4 and 188.1 kJ gull(-1) day(-1) during incubation, h atching and brooding respectively; these values range between 15 and 2 7%, with a maximum of 40%, of the basic daily energy requirements of k elp gulls. Total consumption rate estimations for the whole population of gulls at Potter Peninsula reached between 3400 and 4800 limpets da y(-1), which represents approximately 10-14% of the total annual limpe t mortality.