First record of common bottlenose dolphin (Tursiops truncatus) in Canadian Pacific waters

Luke R Halpin,John K B Ford,Jared R Towers

doi:10.1186/s41200-018-0138-1

Luke R Halpin, John K B Ford + Show 1 more

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https://doi.org/10.1186/s41200-018-0138-1

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Abstract

BackgroundCommon bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warm-temperate waters with coastal and offshore ecotypes known. In the eastern North Pacific Ocean, common bottlenose dolphins are typically found in offshore waters as far as 41° N and in coastal waters as far as 38° N. Despite considerable survey effort, the species has not been previously recorded in Canadian Pacific waters.ResultsOn 29 July 2017, a group of approximately 200 common bottlenose dolphins were observed together with approximately 70 false killer whales (Pseudorca crassidens) in waters of 16.5° C at 50° N during a pelagic seabird and marine mammal survey off the west coast of northern Vancouver Island, British Columbia, Canada.ConclusionsThis sighting represents the only occurrence of common bottlenose dolphins recorded in Canadian Pacific waters and, to our knowledge, is the most northerly record for this species in the eastern North Pacific. It is also the first sighting record of false killer whales in non-coastal waters in British Columbia, Canada. The occurrence of both species may be associated with a prolonged period of warming in offshore regions of the eastern North Pacific.

Highlights

Common bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warmtemperate waters with coastal and offshore ecotypes known
In the eastern North Pacific two ecotypes of common bottlenose dolphin are recognized: a coastal ecotype is typically found in coastal waters (i.e. < 1km from shore) from Ensenada, Mexico (31° N) in the south to as far north as San Francisco (38° N) (Bearzi 2005; Carretta et al 1998; Defran et al 1999); and an offshore ecotype is typically found in offshore waters (i.e. > 1km from shore) as far north as 41° N (Bearzi et al 2009; Defran and Weller 1999)
Approximately 200 apparently healthy bottlenose dolphins of mixed age classes were observed traveling in an aggregation with approximately 70 false killer whales (Pseudorca crassidens) at 06:45 a.m. on 29 July 2017 (Fig. 1)

Summary

Introduction

Common bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warmtemperate waters with coastal and offshore ecotypes known. In the eastern North Pacific Ocean, common bottlenose dolphins are typically found in offshore waters as far as 41° N and in coastal waters as far as 38° N. The common bottlenose dolphin (Tursiops truncatus) is distributed widely in tropical and temperate waters of the North and South Pacific, Atlantic and Indian Oceans (Jefferson et al 2015). Bottlenose dolphins were originally recognized as one species, but have been split into T. truncatus – the common bottlenose dolphin – and T. aduncus – the Indo-Pacific bottlenose dolphin, which is typically found in warm-temperate and tropical waters of the Indian and western Pacific Oceans (Jefferson et al 2015). In the eastern North Pacific two ecotypes of common bottlenose dolphin are recognized: a coastal ecotype is typically found in coastal waters (i.e. < 1km from shore) from Ensenada, Mexico (31° N) in the south to as far north as San Francisco (38° N) (Bearzi 2005; Carretta et al 1998; Defran et al 1999); and an offshore ecotype is typically found in offshore waters (i.e. > 1km from shore) as far north as 41° N (Bearzi et al 2009; Defran and Weller 1999)

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