ESTIMATED FOOD-CONSUMPTION BY PENGUINS AT THE PRINCE-EDWARD-ISLANDS

The consumption of food by the four species of breeding penguins at th e Prince Edward Islands is assessed on an annual and seasonal basis. T otal annual food consumption was estimated at 880 000 t, of which king penguins accounted for 74%, macaroni penguins 21%, rockhopper penguin s 5% and gentoo penguins <1%. Pelagic fish, almost entirely myctophids , were the most important prey (70% of total prey biomass), followed b y pelagic crustaceans (18%) and cephalopods (11%). Demersal fish and b enthic crustaceans accounted for <1% of total consumption, being consu med only by gentoo penguins. Peak demands of between 2 and 3.3 x 10(6) kg d-1 occurred from October-December when three of the four species were breeding, including the two demi-populations of king penguins. Fo od demand decreased to 1.2 x 10(6) kg d-1 during winter when only king and gentoo penguins were present. Much of the prey are presumably cap tured within 300 km of the islands. Assuming an even distribution of f oraging effort within their respective foraging ranges, rates of food transferred to penguins in November ranged from 4.1 x 10(-3) g m-2 d-1 for macaroni penguins to 1.24 x 10(-2) g m-2 d-1 for king penguins. I n mid-July, transfer rates to king and gentoo penguins were 3.9 x 10(- 3) g m-2 d-1 and 6.7 x 10(-3) g m-2 d-1, respectively. The importance of pelagic myctophid fish to penguin populations at the Prince Edward Islands is clear.