“Filling the groove: Energy flow to seabirds in the Beagle Channel, Tierra del Fuego, Argentina”

A RAYA REY; A SCHIAVINI

ECOLOGÍA AUSTRAL

Asociación Argentina de Ecología

Lugar: Buenos Aires, Argentina; Año: 2001 vol. 11 p. 115 - 122

0327-5477

Abstract: We assessed the energy requirements and the food consumption of the seabird community of the Beagle Channel in the summer season. Moreover, we evaluate differences in energy flow among zones establish a priori in the study area, among species and between species with different foraging strategies (surface and diver feeders). We reassessed data on densities of seabirds in the Beagle Channel (February and March 1997) into energy demands. Energy flow to seabirds in shallow waters was twice the one in deep waters. Average energy flow in the whole study area was 9.46 *104 ± 3.2*104  KJ km-2 day-1. The energy intake rates range from 4 to 13*104 KJ Km-2 day-1, being higher in zones which includes breeding sites or close to them. The imperial cormorant was the major contributor to energy flow in all the zones followed by the black- browed albatross. Kelp gull was the major contributor in areas where food from antropic origin was available. Energy flow was similar in four zones, which may be representing a saturation point for seabird biomass in the Beagle Channel. Energy flow to surface and diver feeders was almost equal in all the zones with a slight difference in two zones. Finally, food consumption was between 1.71 - 3.42 tonne day-1, being higher near breeding colonies and lower in areas of more open waters.