Sowerby's beaked whale (''Mesoplodon bidens''), also known as the North Atlantic or North Sea beaked whale, is a species of
toothed whale. It was the first
mesoplodont whale to be described.
James Sowerby, an
English naturalist and
artist
An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating an art. The common usage in both everyday speech and academic discourse refers to a practitioner in the visual arts only. However, th ...
, first described the species in 1804 from a skull obtained from a male that had stranded in the
Moray Firth
The Moray Firth (; Scottish Gaelic: ''An Cuan Moireach'', ''Linne Mhoireibh'' or ''Caolas Mhoireibh'') is a roughly triangular inlet (or firth) of the North Sea, north and east of Inverness, which is in the Highland council area of north of Scotl ...
,
Scotland, in 1800. He named it ''bidens'', which derives from the two teeth present in the jaw, now known to be a very common feature among the
genus.
Physical description
File:Mesoplodon bidens.jpg, Profile of an adult female
File:Mesoplodon bidens British mammals (Pl. 46) (21866206616).jpg, Adult male
File:Head of male Mesoplodon bidens.jpg, Adult male head, showing teeth.
Sowerby's beaked whale has a typical body shape for the genus, and is mainly distinguished by the male's dual teeth positioned far back in the mouth. The whale's beak is moderately long, and the
melon is slightly convex. The colouration pattern is a grey with light
countershading on the bottom, and frequently has
cookie cutter shark
The cookiecutter shark (''Isistius brasiliensis''), also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been reco ...
bites and scars from teeth (in males). The whale reaches 5 metres (16 ft) in females and 5.5 metres (18 ft) in males, with a weight of 1000-1300
kilogram
The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially ...
s (2200-2900 lb). The gestation period lasts for 12 months and the young are born at a length of 2.4 to 2.7 metres (8 to 9 ft) with a weight of around 185 kilograms (400 lb).
Diet
The diet of Sowerby's beaked whales consists of squid and small fish.
Population and distribution
Sowerby's beaked whale ranges from
Nantucket
Nantucket () is an island about south from Cape Cod. Together with the small islands of Tuckernuck and Muskeget, it constitutes the Town and County of Nantucket, a combined county/town government that is part of the U.S. state of Massachuse ...
to
Labrador in the western North Atlantic and from
Madeira
)
, anthem = ( en, "Anthem of the Autonomous Region of Madeira")
, song_type = Regional anthem
, image_map=EU-Portugal_with_Madeira_circled.svg
, map_alt=Location of Madeira
, map_caption=Location of Madeira
, subdivision_type=Sovereign st ...
to the
Norwegian Sea in the eastern North Atlantic. They typically range in waters 200 to 1,500 metres (650 to 5,000 ft) deep. No population estimates have been made. In 1991, there were about 90 records of the species, 80 from the eastern North Atlantic and less than ten from the western North Atlantic; the majority of the records are from around the British Isles.
On 10 January 2009, a female Sowerby's beaked whale was found at the port of
Fethiye on the
Aegean coast of
Turkey, far away from her natural habitat. The whale was successfully saved and released back to the open sea.
On 25 July 2015, biologists with the
New England Aquarium
The New England Aquarium is a public aquarium located in Boston, Massachusetts. The species exhibited include harbor and northern fur seals, California sea lions, African and southern rockhopper penguins, giant Pacific octopuses, weedy seadra ...
investigated the death of a beaked whale in
Massachusetts. The carcass of the long female, which weighed almost , was found on Plymouth Long Beach in
Plymouth, Massachusetts
Plymouth (; historically known as Plimouth and Plimoth) is a town in Plymouth County, Massachusetts, United States. Located in Greater Boston, the town holds a place of great prominence in American history, folklore, and culture, and is known as ...
. Biologists from the aquarium and the International Fund for Animal Welfare said they would perform a necrospy at the
Woods Hole Oceanographic Institution. The whale was initially identified as a Sowerby's beaked whale, but the aquarium said a more thorough examination and consultation with additional experts was needed as staff had not seen a beaked whale since 2006.
On 26 October 2018, a whale was found beached near the town of
Saltdean, on the
UK coast. The carcass was subsequently taken to the
Natural History Museum, London for post-mortem. On 29 August 2019, a stranded whale was rescued from
Dungarvan Bay, in southeast
Ireland. On the 4th July 2020, a whale became disorientated and strayed into
Wicklow, harbour on the east coast of
Ireland but was later discovered dead on
Wicklow, beach.
On 21 August 2020, a 3.86-metre (12.66 ft) female Sowerby's beaked whale washed up on the shore of a beach in
Caister-on-Sea, Norfolk. Emergency services assisted the whale out to sea in an attempt to encourage the animal to live. Unfortunately the next morning a report was received to suggest the whale was stranded and deceased at
Lowestoft
Lowestoft ( ) is a coastal town and civil parish in the East Suffolk district of Suffolk, England.OS Explorer Map OL40: The Broads: (1:25 000) : . As the most easterly UK settlement, it is north-east of London, north-east of Ipswich and sou ...
, on the UK coast, following reported sights of 2 whales in the nearby towns of
Brancaster and
Blakeney in Norfolk earlier in the month.
On successive days in October 2020, two Sowerby's Beaked whales were washed up on separate beaches in East Lothian. Both animals died. Post-mortems are due to be carried out by the National Museum of Scotland.
Behaviour
Sowerby's beaked whales are reclusive creatures that stay away from ships and are rarely sighted. The whales are occasionally in groups of 8 to 10 individuals (males, females, and calves) and have been known to strand in groups as well. They are believed to primarily feed on
squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
and
mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
s, but
cod
Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...
has also been found in their stomachs. They have been known to dive down at times approaching 30 minutes.
Conservation
The species has been hunted infrequently by
Norwegians, but such practices have long since been abandoned. There are some deaths due to entanglement in
fishing gear
Fishing tackle is the equipment used by anglers when fishing. Almost any equipment or gear used in fishing can be called fishing tackle, examples being hooks, lines, baits/ lures, rods, reels, floats, sinkers/ feeders, nets, stringers/ ke ...
, but it is unlikely to be very damaging to the species. Sowerby's beaked whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (
ASCOBANS) and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (
ACCOBAMS
The Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic Area, or ACCOBAMS, is a regional international treaty that binds its States Parties on the conservation of Cetacea in their territories. ...
). The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia
Western African Aquatic Mammals MoU.
/ref>
See also
* List of cetaceans
Notes
References
*
*''Encyclopedia of Marine Mammals''. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002.
*''Sea Mammals of the World''. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002.
External links
Whale & Dolphin Conservation Society (WDCS)
{{Taxonbar, from=Q215335
Mesoplodont whales
Cetaceans of the Atlantic Ocean
Fauna of Scandinavia
Mammals described in 1804