Use of Satellite Information to Understand the Effect of Climatic Variables on the Distribution of Elephant Seals in North American and Arctic Waters
[12-Nov-2013] Gomez, J.J. and Cassini, M.H.
Presented at the 2013 Aquarius/SAC-D Science Team Meeting
Northern elephant seals Mirounga angustirostris
are among the most sexually dimorphic and polygynous species of all mammals, and they show spatial segregation between males and females. The objective of this work was to correlate female and male foraging distributions of these seals with main climatic variables at a biogeographical scale in North Pacific and Arctic waters. We used satellite, website and bibliographical sources to obtain information on adult elephant seal distribution and environmental predictors (surface and bottom sea temperatures, productivity and bathymetry) and three species distribution models [maximum entropy model, environmental niche factor analysis and based on climatic envelopes (BIOCLIM)] to predict the habitat suitability of ocean regions. BIOCLIM provided the best fit. Sea surface and bottom temperatures were the variables with the highest explanatory power for females, while bathymetry was for males. Predictive maps suggest that low temperatures constrain female, but not male, distribution at high latitudes. We suggest that large size increases foraging efficiency of males because, among other benefits, it augments thermal insulation, improving the use of cold, rich sectors of the ocean. Different thermoregulatory abilities between sexes due to size dimorphism should be a complementary explanation of sexual segregation in elephant seals.