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Consumption of marine resources by seabirds and seals in Crozet and Kerguelen waters: changes in relation to consumer biomass 1962–85

Published online by Cambridge University Press:  12 May 2004

C. Guinet
Affiliation:
Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
Y. Cherel
Affiliation:
Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
V. Ridoux
Affiliation:
Océanopolis, Port de Plaisance du Moulin Blanc, BP 411, 29275 Brest Cedex, France
P. Jouventin
Affiliation:
Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France

Abstract

The total annual food consumption of the seabird and seal community breeding at lles Kerguelen was estimated to be 1.8×106 t in 1985. This biomass included c. 0.99×106 t (55%) of crustaceans, 0.46×106 t (26%) of myctophid fish, 0.07×106 t (4%) of other fish species, and 0.26×106 t (15%) of squid. During the same year, the mass of prey consumed in Crozet waters was previouly estimated to be 3.1×106 t, the total food consumption in the Indian Ocean area including the two archipelagos thus totalling c. 5×106 t in 1985. Four species of top predators, the king penguin, macaroni penguin, elephant seal, and fur seal, consumed 59% and 56% of the amount of prey eaten in 1985 by the whole community at Kerguelen and Crozet islands, respectively. Between 1962 and 1985, population changes of these four species induced 18 and 41% increases in their food consumption at Kerguelen and Crozet islands. Population changes included a moderate increase in the number of macaroni penguins and a marked rise of king penguin populations. Assuming that the diet of king penguin was similar in 1962 and 1985, its population increase will have required a concomitant increase of 0.6×106 t in the consumption of myctophid fish in Crozet and Kerguelen waters.

Type
Papers—Life Sciences and Oceanography
Copyright
© Antarctic Science Ltd 1996

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