Mesoplodon bidens 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Ziphiidae

Scientific Name: Mesoplodon bidens (Sowerby, 1804)
Regional Assessments:
Common Name(s):
English Sowerby's Beaked Whale, North Atlantic Beaked Whale
French Mésoplodon de Sowerby
Spanish Ballena de Pico de Sowerby, Zifio de Sowerby
Physeter bidens Sowerby, 1804

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L.
Reviewer(s): Hammond, P.S. & Perrin, W.F. (Cetacean Red List Authority)
There is no information on global abundance or trends in abundance for this species. It is not believed to be uncommon but it is potentially vulnerable to low-level threats and a 30% global reduction over three generations cannot be ruled out (criterion A).
Previously published Red List assessments:

Geographic Range [top]

Range Description:Sowerby's beaked whales are known almost exclusively from the colder waters of the North Atlantic, from at least Massachusetts, USA to Labrador, Canada in the west, and from Iceland to Norway in the east (Mead 1989; MacLeod et al. 2006). This is the most northerly distributed of the Atlantic species of Mesoplodon, with most records north of 30°N. There are a number of strandings or sightings considered to be extralimital in the Mediterranean Sea, and from the Gulf of Mexico side of Florida.
Countries occurrence:
Belgium; Canada; Denmark; France; Germany; Gibraltar; Iceland; Ireland; Netherlands; Norway; Portugal; Spain; Sweden; United Kingdom; United States
FAO Marine Fishing Areas:
Atlantic – northeast; Atlantic – northwest; Atlantic – eastern central
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Very little is known of the population biology of this species. It is one of the most commonly seen mesoplodonts in some parts of its range.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:As with other members of the genus, these whales occur almost exclusively in deep waters past the continental shelf edge. Although it is one of the most commonly stranded Mesoplodon species, there have been few sightings at sea, and it is poorly known. De Buffrénil (1995) mentioned that two sightings were north of Scotland and west of the Orkney Islands, in waters several 100 m deep. Hooker and Baird (1999) observed groups of Sowerby's Beaked Whales in the Gully, a submarine canyon off eastern Canada, on four occasions. Sightings were in water depths of between 550 m and 1,500 m.

Ostrom et al. (1993) evaluated the diet of Sowerby's beaked whales, based on isotopic comparisons among northwestern Atlantic cetaceans. They feed on squid and fish, including Atlantic cod (Gadus morhua).

Threats [top]

Major Threat(s): There is little specific information on the status or threats to whales of this species (Reeves et al. 2003). However, some are known to have been incidentally killed by whalers in Newfoundland, Iceland, and in the Barents Sea. A few entanglements in fishing gear (e.g., driftnets) have been documented. Waring et al. (2001) reported that for 1989-1998 observed bycatch in pelagic drift gillnets along the US East Coast amounted to 24 Sowerby's beaked whales. These were caught exclusively in the area from Georges Canyon to Hydrographers Canyon, along the continental shelf break and continental slope during July-October. This fishery has now been closed.

This species, like other beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration (Cox et al. 2006).

Evidence from stranded individuals of several similar species indicates that they have swallowed discarded plastic items, which may eventually lead to death (e.g. Scott et al. 2001); this species may also be at risk.

Predicted impacts of global climate change on the marine environment may affect this species of whale, although the nature of impacts is unclear (Learmonth et al. 2006).

Conservation Actions [top]

Conservation Actions: The species is listed in Appendix II of CITES. Research is needed to determine the impacts of potential threatening processes on this species.

Citation: Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. 2008. Mesoplodon bidens. The IUCN Red List of Threatened Species 2008: e.T13241A3424903. . Downloaded on 23 September 2018.
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