AN INTERGENERIC HYBRID IN THE FAMILY PHOCOENIDAE

A 60-cm female fetus recovered from a Dall's porpoise (Phocoenoides da lli) found dead in southern British Columbia was fathered by a harbour porpoise (Phocoena phocoena). This is the first report of a hybrid wi thin the family Phocoenidae and one of the first well-documented cases of cetacean hybridization in the wild. In several morphological featu res, the hybrid was either intermediate between the parental species ( e.g., vertebral count) or more similar to the harbour porpoise than to the Dall's porpoise (e.g., colour pattern, relative position of the f lipper, dorsal fin height). The fetal colour pattern (with a clear mou th-to-flipper stripe, as is found in the harbour porpoise) is similar to that reported for a fetus recovered from a Dall's porpoise to off C alifornia. Hybrid status was confirmed through genetic analysis, with species-specific repetitive DNA sequences of both the harbour and Dall 's porpoise being found in the fetus. Atypically pigmented porpoises ( usually traveling with and behaving like Dall's porpoises) are regular ly observed in the area around southern Vancouver Island. We suggest t hat these abnormally pigmented animals, as well as the previously note d fetus from California, may also represent hybridization events.