Influence of thermal fronts on habitat selection by rorqual whales in the Gulf of St. Lawrence

Abstract:

Many studies have tried to link the distribution of cetaceans with basic environmental features such as underwater topography and sea surface temperature (SST). However, the mechanisms underlying these relationships are still poorly understood. Some studies have proposed that thermal fronts, present in the ocean at many spatial scales, could act as mechanisms that increase biological productivity and aggregate prey species like euphausiids and fish. The aim of this project was to quantify the relationship between these fronts and the distribution patterns of four species of rorqual whales in the Gulf of St. Lawrence . We used 61 satellite maps of surface temperatures to locate thermal fronts and compare their distribution to 1102 sightings of whales collected from boat surveys between 1996 and 2002. The results of random resampling and Mantel tests of matrix similarity showed strong quantitative correlations between whale distribution patterns and the presence of thermal fronts, as well as differences between species that may reflect different feeding strategies.

Doniol-Valcroze, T., P. Larouche, D. Berteaux and R. Sears. 2005. Influence of thermal fronts on habitat selection by rorqual whales in the Gulf of St. Lawrence . Oral presentation to the 44th Annual Conference of the Canadian Society of Zoologists, Kingston , May 11-14, 2005.