“Inter-annual variation in the diet of female southern rockhopper penguin (Eudyptes chrysocome chrysocome) at Staten Island and prey relationships of the food web in the study area”

A RAYA REY; A SCHIAVINI

POLAR BIOLOGY

Springer Verlag

Lugar: Heidelberg; Año: 2005 vol. 28 p. 132 - 141

0722-4060

Abstract: Inter-annual variation in the diet of female southern rockhopper penguins at Staten Island was studied during the early chick-rearing period to investigate the components of the diet and highlight some points of the possible food web in the study area. Gregarious crustaceans, small juveniles of squid and octopus, fish larvae and ºjuvenile fish dominated the diet. There was a high degree of variability in the relative contribution of the different prey taxa during the three seasons studied. Overall, crustaceans were by far the most abundant in terms of number. Cephalopods contributed less to numbers, while fish was the least represented of the prey item in two years. Inter-annual variation in the proportion of prey items consumed was apparent only for some prey species: Thysanoessa gregaria, Gonatus antarcticus, Themisto gaudichaudii, Harpagifer bispinis and Salilota australis. These data suggests variability in the prey resources at sea during the study period and a subsequent opportunism of this penguin species to exploit what is differentially available. In terms of the food web in the area we suggest an apparent relationship in the availability between Themisto gaudichaudii and Gonatus antarcticus, and between Themisto gaudichaudii and Harpagifer bispinnis. These relationships remark the importance of understanding food web interactions, especially those involving multiple trophic levels, when determining the role of upper-trophic level predators in marine systems.