Seasonal variation in the number of breeding females of Southern Elephant Seal, at Isla 25 de Mayo/King George

30. MENNUCCI J.A., NEGRETE J., JUÁRES M.A., SANTOS M.M., CORIA N.R., MÁRQUEZ M.E.

Conferencia; XXXII SCAR & OPEN SCIENCE CONFERENCE. Portland, Oregón, Estados Unidos.; 2012

The effects of global warming on pinnipeds populations are evident mainly during the breeding season or the preceding months, due to variations in the availability of breeding sites or wintering habitats, or related to changes in the abundance and distribution of its principal prey-items. Between 1980 and 1990, the breeding population size of Southern Elephant Seals at Isla 25 de Mayo, South Shetland Islands has declined. The number of females that attend to reproduce represents an index of pup production and the potential recruitment in subsequent years. Given that this species is polyginic, it provides a partial but accurate estimation of the population trend. Between 1995 and 2010 seasons, at Stranger Point, Isla 25 de Mayo, surveys of females were conducted during the breeding haul-out period. Available data reflects an inter-annual fluctuation in the maximum number of females through the seasons, and an intrinsic rate of natural change (r) = -0.025. The number of females breeding at Stranger Point and the extent of sea ice recorded in the west of the Antarctic Peninsula (average from July-September) show a significant positive linear relationship (R2= 0.52, P=0.004, N=14). Possible causes of the found results are discussed in the light of the environmental variability recorded as consequence of global climate change.