Common bottlenose dolphins, typically associated with tropical and warm-temperate waters, have been observed for the first time off Canada’s Pacific coast.
About 200 of the dolphins were observed travelling with about 70 false killer whales on July 29 last year during a pelagic seabird and marine mammal survey from the Canadian Coast Guard research ship John P. Tully.
The discovery, published Thursday in the journal Marine Biodiversity Records, occurred in waters that were 16.5 degrees Celsius, believed to be related to a period of warming in the eastern North Pacific.
Biologist Luke Halpin, lead author of the paper, said it was “special and rare” to observe the two cetacean species travelling together in B.C. waters. A handful of northern right-whale dolphins also swam close by.
The Tully was located about 180 kilometres off northwestern Vancouver Island and to the south of Delwood Seamounts in waters about 2,500 metres deep. The encounter lasted about 40 minutes.
The dolphins displayed short- to moderate-length stocky beaks, and were generally light grey to almost black on the back and sides, fading to white on the belly.
The location of the sighting is about 1,000 kilometres north of the typical range of common bottlenose dolphins off the west coast of North America. Over the years, there have been occasional sightings and strandings of the species in Washington state, but nothing to match this latest congregation off B.C.
Most prior sightings of false killer whales in B.C. have involved small groups of about a dozen animals travelling southern inland waters. One individual known as Willy, or Westshore Willy, made his home in local waters, including the port at Roberts Bank, from 1990 to 2003 and may have been the last remaining member of a group that wandered into B.C. waters in 1987.
This sighting of common bottlenose dolphins and false killer whales follows a warming trend in the eastern North Pacific from 2013 to 2016 that brought unusual species northward, according to the paper. The trend appeared to continue into July, with temperatures up to about 1.7 Celsius warmer throughout the North Pacific.
In March this year, the Vancouver Sun reported two other unusual sightings by Halpin off B.C.’s west coast — a swordfish, on Sept. 5, 2017, about 37 kilometres from Brooks Peninsula, and a loggerhead turtle on Feb. 22, 2015, about 83 kilometres west of Tofino.
Canada’s exclusive economic zone in the Pacific extends 370 kilometres off the B.C. coast.
