Intraspecific dietary variation in the short-beaked common dolphin Delphinus delphis in the Bay of Biscay: importance of fat fish

摘要: Investigations of trophic interactions between marine mammals and resources typically use models that are based on food composition, energy content the prey requirements predators. Although diets known to vary intraspecifically accord- ing year, season, sex age, this variation is rarely taken into account in published models. The aim present study was assess diet short-beaked common dolphin Delphinus del- phis Bay Biscay (France), examine intraspecific dietary explore its effects calculated daily intake. Stomach contents were analysed from 71 dolphins stranded along French coast 1999 2002. composition fresh fraction quantified by occurrence, relative abundance, reconstructed mass size distributions for all taxa. Overall, most important species sardine, anchovy, sprat horse mackerel, which represented 44.9, 22.6, 8.0 5.0% diet, respectively. composi- tion displayed significant relation season sex/maturity status, terms both distributions. Temporal interpreted availability Biscay. Because different types have energetic values, changes could lead estimated total biomass needed fulfil requirements. In spite main varying ex- tensively, intakes changed relatively little because included a high proportion fat fish (73 93% mass).