(…) The harbor porpoise (Phocoena phocoena) is found in coastal temperate and subarctic waters of the Northern Hemisphere (Gaskin et al. 1974). Although the species’ biology has been well documented throughout much of its range (see Gaskin et al. 1974, Prescott and Fiorelli 1980 for review), knowledge of its behavior and social structure is minimal. Furthermore, little information is available on free-ranging harbor porpoises in Canadian waters, except for the Bay of Fundy and Gulf of Maine, where long-term studies are currently in progress (e.g., Gaskin et al. 1985, Gaskin and Watson 1985, Read and Gaskin 1988).
I here describe an unusual aggregation of harbor porpoises in the Jacques Cartier Passage, Gulf of St. Lawrence, Canada. Although consisting of a single observation, the findings provide some insight into the social behavior of harbor porpoises.
On 23 August 1987 a large number of harbor porpoises, estimated at 800, was sighted opportunistically at noon off the coast at Anse du Castor (49°48’N 63°27’W), Anticosti Island. (…)