Abstract:
Understanding the distribution and foraging ecology of major consumers within
pelagic systems, specifically in relation to physical parameters, can be important
for the management of bentho-pelagic systems undergoing rapid change
associated with global climate change and other anthropogenic disturbances
such as fishing (i.e., the Antarctic Peninsula and Scotia Sea). We tracked 11
adult male southern elephant seals (Mirounga leonina), during their five-month
post-moult foraging migrations from King George Island (Isla 25 de Mayo),
northern Antarctic Peninsula, using tags capable of recording and transmitting
behavioural data and in situ temperature and salinity data. Seals foraged mostly
within the Weddell Scotia Confluence, while a few foraged along the western
Antarctic Peninsula shelf of the Bellingshausen Sea. Mixed model outputs
suggest that the at-sea behaviour of seals was associated with a number of
environmental parameters, especially seafloor depth, sea-ice concentrations
and the temperature structure of the water column. Seals increased dive bottom
times and travelled at slower speeds in shallower areas and areas with increased
sea-ice concentrations. Changes in dive depth and durations, as well as relative
amount of time spent during the bottom phases of dives, were observed in
relation to differences in overall temperature gradient, likely as a response to
vertical changes in prey distribution associated with temperature stratification
in the water column. Our results illustrate the likely complex influences of
bathymetry, hydrography and sea ice on the behaviour of male southern
elephant seals in a changing environment and highlight the need for regionspecific
approaches to studying environmental influences on behaviour.
