Caloric content of fish preys of Antarctic pinnipeds

MARQUEZ M.; CASAUX R,; BARONI A.; BERTOLIN M.; CARLINI A.

Buenos Aires

Congreso; Scientific Committee on Antarctic Research Open Science Conference; 2010

Scientific Committee on Antarctic Research

Demersal-benthic fish are links between lower and upper levels of the food web andare common prey of seals. The present study was focused on the determination of the grossenergy provided by some of these fish species and of their role in the diet of two pinnipedspecies, the Antarctic fur seal Arctocephalus gazella and the Weddell seal Leptonychotesweddellii., at different Antarctic localities. Thirty seven specimens belonging to the families:Nototheniidae (Notothenia rossii, Gobionotothen gibberifrons, Lepidonotothen nudifrons,Trematomus newnesi, T. bernacchii); Bathydraconidae (Parachaenichthys charcoti) andChannichthyidae (Chaenocephalus aceratus), were analysed (size range 17.2 – 56.2cm).The mean caloric values (wet weight) in whole fish was determined by Ballistic Bombcalorimetry and ranged between 3.19 – 5.54 kJ g -1. Within species the observed energeticvalues were significantly different (ANOVA, F=5.34; df 6; p<0.01). The lowest values wereobserved in T. newnesi (Newman-Keuls, p<0.05) whereas the highest ones were observedin L. nudifrons (p<0.05). The knowledge of the energetic value of prey species is of particularimportance to understand the process determining the selection of the main food items.