DISTRIBUTION AND HABITAT PARTITIONING BY SMALL ODONTOCETES IN THE GULLY, A SUBMARINE-CANYON ON THE SCOTIAN-SHELF

In this paper we examine the summer distribution of three species of s mall odontocetes in the highly productive waters in and near the Gully , a submarine canyon on the edge of the Scotian Shelf. Atlantic white- sided dolphins (Lagenorhynchus acutus) and common dolphins (Delphinus delphis) were not randomly distributed with respect to depth, sea-floo r relief, month of sighting, or sea-surface temperature. Long-finned p ilot whales (Globicephala melas) were not randomly distributed with re spect to month or sea-surface temperature. These species used the Gull y slightly differently, although there was overlap. White-sided dolphi ns were seen only in the core of the canyon, but were sighted at all t emperatures, depths, and sea-floor reliefs and throughout the summer f ield season. Common dolphins had a modest range throughout the deeper waters and were not seen in the summer before July, when the water war ms. Pilot whales ranged widely over the study area, preferring areas w ith fairly flat relief and were more common later in the summer, when the waters were warmer. It appears that white-sided and common dolphin s partition the Gully temporally but not geographically.