Predictions of critical habitat for five whale species in the waters of coastal British Columbia

Abstract

Whaling records from British Columbia coastal whaling stations reliably report the positions of 9592 whales killed between 1948 and 1967. We used this positional information and oceanographic data (bathymetry, temperature, and salinity) to predict critical habitat off the coast of British Columbia for sperm (Physeter macrocephalus), sei (Balaenoptera borealis), fin (Balaenoptera physalus), humpback (Megaptera novaeangliae), and blue (Balaenoptera musculus) whales. We used generalized linear models at annual and monthly time scales to relate whale occurrence to six predictor variables (month, depth, slope, depth class, and sea surface temperature and salinity). The models showed critical habitat for sei, fin, and male sperm whales along the continental slope and over a large area off the northwest coast of Vancouver Island. Habitat models for blue, humpback, and female sperm whales were relatively insensitive to the predictor variables, owing partially to the smaller sample sizes for these groups. The habitat predictions lend support to recent hypotheses about sperm whale breeding off British Columbia and identify humpback whale habitat in sheltered bays and straits throughout the coast. The habitat models also provide insights about the nature of the linkages between the environment and the distribution of whales in the North Pacific Ocean.