Food consumption estimates of southern elephant seal females at Isla 25 de Mayo (King George island), Antartica

CARLINI, A.R., DANERI, G.A., MÁRQUEZ, M.E.I., NEGRETE, J., MENNUCCI, J., JUARES, M

Conferencia; XXXI SCAR Open Science Conference; 2010

The food and energy requirements of the female component of the southern elephant seal population at Stranger Point, Isla 25 de Mayo (King George) were assessed by combining data on the energy costs of reproduction, moult, growth and foraging with population size, age structure and diet composition. The estimated energy expenditure of individual females increased until they were 9-10 years of age, after which it stabilized around 19,000 MJ/year. An adult female spent around 24% of this energy on reproduction(including maintenance costs and energy delivered to its pups), and 64% during the foraging phases. Energy expenditure on growth was relatively important, amounting to approximately 9-15% of the annual energy budget, until females were 4 years old, but it represented less than 5% in older animals. The energy expenditure of the female component of the Stranger Point population was estimated to be 1.34 x 10 MJ/year, while gross energy requirements . Assuming an average diet composition of 50% fish and 50% cephalopods by mass with a mean energy density of 4.9 MJ/kg, the female population at Stranger Point would require an annual biomass consumption of 1,780 tonnes of fish and 1,780 tonnes of cephalopods MJ/year, while gross energy requirements were estimated to be 1.75 x 10 MJ/year. Assuming an average diet composition of 50% fish and 50% cephalopods by mass with a mean energy density of 4.9 MJ/kg, the female population at Stranger Point would require an annual biomass consumption of 1,780 tonnes of fish and 1,780 tonnes of cephalopods MJ/year.