Distribution of the leatherback turtle (Dermochelys coriacea) in Atlantic Canada: Evidence from an observer program, aerial surveys, and a volunteer network of fish harvesters

The globally endangered leatherback turtle (Dermochelys coriacea ) occurs seasonally in the waters off Atlantic Canada; however, the significance of these waters to this species has not been previously clarified due to a paucity of records. To enhance the collection of leatherback turtle biological and environmental data in this region, a volunteer network of commercial fishers and whale watch operators was established (The Nova Scotia Leatherback Turtle Working Group). In 1998, this group reported the details of 171 geo-referenced sightings of leatherbacks. These records, combined with others collected from an observer program and aerial surveys, provide new insight into the spatial and temporal distribution of leatherbacks in Atlantic Canada. Leatherback density was highest in August and the majority of turtles were observed inshore from the continental shelf break (200m isobath). Mean sea surface temperature (SST) associated with 1998 sightings was 17.8°C. Records from temperate and boreal latitudes (where SST < 5°C) attest to this species' remarkable capacity for endothermy. Medusivory was confirmed by photo-documented feeding behaviour in nine turtles. The results of this study suggest that eastern Canadian waters are within the regular range of large numbers of migrating leatherbacks and should be considered critical seasonal foraging habitat for this species.