FISH AND SQUID IN THE DIET OF KING PENGUIN CHICKS, APTENODYTES PATAGONICUS, DURING WINTER AT SUB-ANTARCTIC CROZET ISLANDS

The diet of king penguins, Aptenodytes patagonicus, rearing chicks was studied during three consecutive austral winters (1990, 1991 and 1992 ) at Crozet Islands. The mean stomach content mass of the 47 samples w as 503 g. Percentages of wet and reconstituted masses showed that both fishes (66 and 36%, respectively) and squid (34 and 64%) are importan t components of the winter diet. Juveniles of the demersal onychoteuth id squid Moroteuthis ingens form the bulk of the cephalopod diet, and this was the main prey by reconstituted mass (57%). Myctophid fish (la ntern-fishes) accounted for most of the fish diet, constituting togeth er 32% by mass. The three main species of myctophids eaten in summer b y king penguins were either very rare in winter (Electrona car lshergi ) or accounted for a smaller proportion of the diet (Krefftichthys and erssoni=1.5% by mass and Protomyctophum tenisoni=4.6%). Five other myc tophids, which are rarely consumed in summer, contributed 24% of the d iet by mass in winter (Gymnoscopelus piabilis=18.1%, Lampichthys proce rus=2.4%, G. nicholsi=1.3%, and Metelectrona ventralis and Electrona s ubaspera=1.0%). The greater diversity of prey in winter suggests a mor e opportunistic feeding behaviour at a time probably marked by a chang e in prey availability, Both the known ecology of the fish and squid p rey and the barely digested state of some items suggest that in winter breeding adults forage in the outer shelf, upper slope and oceanic ar eas in the close vicinity of the Crozet Islands to feed their chicks. Finally, using king penguins as biological samplers, the present work provides novel data on the previously unstudied mesopelagic/epibenthic marine community in waters surrounding the Crozet Islands. Seventeen myctophid fish have been identified to species level. These include se veral poorly known species in the southern Indian Ocean. The occurrenc e of small, nearly intact, cephalopods in the diet of king penguins su ggests that spawning grounds of four squid species may be located near the Crozet Archipelago.