INVESTIGADORES
CASAUX Ricardo Jorge
artículos
Título:
On the accuracy of the pellet analysis method to estimate the food intake in the Antarctic shag, Phalacrocorax bransfieldensis
Autor/es:
CASAUX RICARDO
Revista:
Folia Zoologica
Referencias:
Año: 2003 vol. 52 p. 167 - 176
Resumen:
Abstract.
The possibility to study quantitatively the diet of the Antarctic
shag Phalacrocorax bransfieldensis by
the analysis of pellets, applying correction factors to compensate for the
digestion and loss through the gastrointestinal tract of fish otoliths
represented in pellets, was evaluated at two localities of the South Shetland
Islands. For such purpose, the
results from the analysis of 566
pellets (=regurgitated casts) collected at Harmony Point, and 296 at Duthoit
Point, throughout the 1995/96 and 1996/97 breeding seasons, were corrected with the mentioned factors and the shag daily
consumption rate was estimated. The
estimations indicated that, except for Duthoit Point in 1996/97, the daily food
intake increased from November to January (pre-laying to late-rearing) and
slightly decreased in February when chicks start to fledge, thus reflecting the
energy requirements at the nest. These
estimations, in general, are in line with those previously obtained for other
colonies and/or shag species by different methods, which suggests that after
correction the use of pellets is an acceptable method to quantify the diet of
the Antarctic Shag.