First Record of Common Bottlenose Dolphin (Tursiops Truncatus) in Canadian Pacific Waters Luke R
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Halpin et al. Marine Biodiversity Records (2018) 11:3 https://doi.org/10.1186/s41200-018-0138-1 MARINE RECORD Open Access First record of common bottlenose dolphin (Tursiops truncatus) in Canadian Pacific waters Luke R. Halpin1,2* , Jared R. Towers3,4 and John K. B. Ford4 Abstract Background: Common 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. Results: On 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. Conclusions: This 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. Keywords: Tursiops truncatus, Common bottlenose dolphin, British Columbia, Pseudorca crassidens,Falsekiller whale, Distribution, Cetaceans Background species groups and for its social interactions with other The common bottlenose dolphin (Tursiops truncatus)is cetaceans, including large whales as well as other dol- distributed widely in tropical and temperate waters of phins (Jefferson et al. 2015). the North and South Pacific, Atlantic and Indian Oceans Genetic differentiation between populations of coastal (Jefferson et al. 2015). Bottlenose dolphins were origin- and offshore common bottlenose dolphins is well known ally recognized as one species, but have been split into throughout the species’ global range (Hoelzel et al. T. truncatus – the common bottlenose dolphin – and T. 1998). In the eastern North Pacific two ecotypes of com- aduncus – the Indo-Pacific bottlenose dolphin, which is mon bottlenose dolphin are recognized: a coastal eco- typically found in warm-temperate and tropical waters type is typically found in coastal waters (i.e. < 1km from of the Indian and western Pacific Oceans (Jefferson et al. shore) from Ensenada, Mexico (31° N) in the south to as 2015). T. truncatus is a relatively large, robust and un- far north as San Francisco (38° N) (Bearzi 2005; Carretta mistakable dolphin most often found in groups of less et al. 1998; Defran et al. 1999); and an offshore ecotype than 20 animals. Large herds, although rare, can occa- is typically found in offshore waters (i.e. > 1km from sionally be seen in offshore areas (Wells and Scott shore) as far north as 41° N (Bearzi et al. 2009; Defran 2018). The species is well-known to occur in mixed- and Weller 1999). The coastal population in United States Pacific coastal * Correspondence: [email protected] waters is estimated to contain at least 450 individuals 1Halpin Wildlife Research, Vancouver, British Columbia, Canada and the offshore population is estimated at 3,495 indi- 2Current address: School of Biological Sciences, Monash University, Melbourne, Victoria, Australia viduals (Perrin et al. 2011). The California coastal popu- Full list of author information is available at the end of the article lation was documented to undergo a northerly range © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Halpin et al. Marine Biodiversity Records (2018) 11:3 Page 2 of 5 extension from southern to central California associated commercial and recreational whale-watching traffic off with warm water influx after the 1982-83 El Niño event British Columbia’s southern coast, no common bottlenose (Wells et al. 1990). Ship-based line-transect cetacean dolphins have been previously documented off Canada’s surveys off the United States west coast have infre- west coast (Ford 2014). However, on 29 July 2017 an un- quently documented the offshore population off north- usually large mixed-species aggregation of toothed ceta- ern California (Barlow 2016). Only three common ceans including common bottlenose dolphins and false bottlenose dolphins have been observed alive further killer whales was observed in British Columbia waters. north in the eastern North Pacific. These occurred in Puget Sound, northern Washington State – one in sum- Methods mer 2010, another in winter 2010-2011 (Cascadia Re- LRH sighted the animals during routine pelagic seabird search Collective 2011). Both animals subsequently and marine mammal surveys aboard the Canadian Coast stranded dead and their carcasses were recovered. In Guard ship John P. Tully – a 69 m offshore oceano- September 2017, a third animal was observed close to graphic science vessel. The initial sighting was made by shore, traveling south near Apple Cove Point in naked eye from the ship’s wheelhouse at a distance of Kingston, Washington State (Frey, unpublished observa- approximately 3000 m from the ship’s stern, and later tion). Two other strandings of this species have also oc- using Swarovski 8.5 x 42 binoculars. Photographs were curred in northern Washington – one near Sequim in taken with a Canon EOS 7D digital camera fitted with a the Strait of Juan de Fuca in 2004 (Cascadia Research 400 mm f/5.6 Canon lens. Collective 2011) and another in Samish Bay in 1988 (Ferrero and Tsunoda 1989). The latter individual was Results verified as belonging to the coastal population and is the Approximately 200 apparently healthy bottlenose dol- most northerly record of this species in the eastern phins of mixed age classes were observed traveling in an North Pacific. These sightings and strandings involved aggregation with approximately 70 false killer whales single individuals of this typically group-living species (Pseudorca crassidens) at 06:45 a.m. on 29 July 2017 and were most likely vagrant or accidental occurrences. (Fig. 1). Soon after the initial sighting, the herd Despite considerable ship-based and aerial survey ef- approached the ship at a distance of not closer than 400 fort for cetaceans off remote regions of British Columbia’s m, at which point the John P. Tully was stopped. The outer and inner coast (Ford et al. 2010;Nicholetal.2017; animals were observed approximately 180 km (sighting Williams and Thomas 2007), and high volumes of location: 50°16.03' N, 130°51.22' W, Fig. 2) offshore of Fig 1 Common bottlenose dolphins (Tursiops truncatus)(a,backgroundc, d) observed on 29 July 2017 in British Columbia waters. Individuals show identifiable morphological characteristics such as short to moderate-length beak, distinctly separated from the melon; gently curved mouth line, dipping downward from the tip of the beak and upwards at the base, and tall, falcate dorsal fins. False killer whales (Pseudorca crassidens) (b,foregroundc, d). Photo: L. Halpin. Halpin et al. Marine Biodiversity Records (2018) 11:3 Page 3 of 5 the northwest coast of Vancouver Island and to the species group provided an additional behavioral clue to south of Delwood Seamounts in waters with a depth of support positive identification of the species. > 2500 m. Sea surface temperature at the time and loca- tion of the sighting, as recorded by the John P. Tully at a Discussion depth of 4.5 m was 16.5°C. This sighting of a large group of common bottlenose Five northern right whale dolphins (Lissodelphis borea- dolphins off the northwest coast of Vancouver Island is lis) were also observed, but did not appear to be socializ- the first confirmed occurrence of the species in Canadian ing nor traveling closely within the larger aggregation of Pacific waters despite significant aerial and ship-based sur- bottlenose dolphins and false killer whales that appeared vey effort over the past 15 years (Ford et al. 2010;Nichol more tightly grouped. The northern right whale dolphins et al. 2017;WilliamsandThomas2007). There are also no tended to remain approximately 100 m distance from stranding records for the species in British Columbia the common bottlenose dolphins and false killer whales. (Ford 2014). The location of this sighting is approximately The animals within the large aggregation were mostly 1000 km north of the typical range of common bottlenose traveling fast, breaching often and porpoising, but they dolphins off the west coast of North America, and repre- occasionally slowed down or stopped and were spyhop- sents the northernmost record of the species in the east- ping at regular intervals throughout the encounter, ern North Pacific. An estimated 200 dolphins were which lasted approximately 40 minutes. By approxi- present in this group, which is an unusually large aggrega- mately 07:25 a.m. the herd had traveled out of sight. tion – group sizes of both inshore and offshore ecotypes Several morphological features, detailed in Jefferson et of the species off California typically average 10–20 ani- al. (2015), were used for positive identification of the mals and large aggregations occur in offshore waters common bottlenose dolphins including: a short to (Wells and Scott 2018; Barlow 2016; Jefferson et al. 2015; moderate-length stocky beak distinctly separated from Defran and Weller 1999).