First Record of a Collapsed Dorsal Fin in a White-beaked Dolphin Lagenorhynchus albirostris, with a Gunshot Wound as a Possible Cause

Abstract

Collapsed dorsal fins are rare in odontocete cetaceans, having been reported for only a few species. We present the first known case in a White-beaked Dolphin (Lagenorhynchus albirostris Gray, 1846), photographed off northern Newfoundland, Canada in September 2004. The animal also had a wound on the right side of its body, anterior to the dorsal fin, with an estimated average diameter of 20-37 mm. We consider this to be a gunshot wound, most likely a 12-gauge rifled slug. The dolphin appeared to be healthy and with no movement problems, and what was apparently the same animal was seen in the same area on several dates during 2005. There is a long history of hunting small cetaceans off the Labrador coast, and a gunshot wound is the most likely cause of the wound observed. The wound may have caused the dorsal fin to collapse, as noted in other dolphin species