A large group of common bottlenose dolphins (Tursiops truncatus) have been spotted in Canadian Pacific waters -- the first confirmed occurrence of the species in this area. The sighting is reported in a study published in the open access journal Marine Biodiversity Records.

On 29 July 2017, researchers from Halpin Wildlife Research, in collaboration with the Department of Fisheries and Oceans, Canada and the Department of Environment and Climate Change, Canada, observed a group of approximately 200 common bottlenose dolphins and roughly 70 false killer whales (Pseudorca crassidens). The sighting occurred off the west coast of northern Vancouver Island, British Columbia, Canada and may be the northern most recording for this species in the eastern North Pacific.

Luke Halpin, lead author of the paper, said: 'It is surprising to find a warm-water dolphin in British Columbian waters, and especially to find such a large number of common bottlenose dolphins within the group."

Halpin added: "The sighting is also the first offshore report of false killer whales in British Columbia. To see the two species traveling together and interacting was quite special and rare. It is known that common bottlenose dolphins and false killer whales seek each other out and interact, but the purpose of the interactions is unclear."

Both common bottlenose dolphins and false killer whales typically live in warm temperate waters further south in the eastern North Pacific, but this sighting suggests that they will naturally range into British Columbia, Canada when conditions are suitable. There has been a warming trend in eastern North Pacific waters from 2013-2016 and the authors hypothesize that the trend may be the reason behind this unusual sighting.

Halpin adds: "Since 2014 I have documented several warm-water species: common bottlenose dolphins, a swordfish and a loggerhead turtle in British Columbian waters. With marine waters increasingly warming up we can expect to see more typically warm-water species in the northeastern Pacific."