Atlantic White-sided Dolphin

Taxobox
name = Atlantic White-sided Dolphin


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image2_caption = Size comparison against an average human
status = LR/lc | status_system = IUCN2.3
regnum = Animalia
phylum = Chordata
classis = Mammalia
subclassis = Eutheria
ordo = Cetacea
subordo = Odontoceti
familia = Delphinidae
genus = "Lagenorhynchus"
species = "L. acutus"
binomial = "Lagenorhynchus acutus"
binomial_authority = (Gray, 1828)
range_

range_map_width = 250px
range_map_caption = Atlantic White-sided Dolphin rangeThe Atlantic White-sided Dolphin ("Lagenorhynchus acutus") is a distinctively coloured dolphin found in the cool to temperate waters of the North Atlantic Ocean.

Taxonomy

The Atlantic White-sided Dolphin was named by Gray in 1828. The specific name "acutus" comes from the Latin for 'pointed' and refers to the sharply pointed dorsal fin. "L. acutus" is one of six oceanic dolphins in the genus "Lagenorhynchus".

Physical description

The dolphin is slightly larger than most other oceanic dolphins. It is just over a metre in length at birth, growing to about 2.8m (males) and 2.5m (females) at maturity. It weighs between 200 kg and 230 kg once fully-grown. Females reach sexual maturity at between 6 and 12 years, and males between 7 and 11 years. The gestation period is 11 months and lactation lasts for about a year and a half - both typical figures for dolphins. Individuals are known to live for up to 22 years (males) and 27 years (females).

The key distinguishing feature is the white to pale yellow patch found behind the dorsal fin of the dolphin on each side. This variation in colour to the Atlantic White-sided Dolphin is unique amongst the mixtures of white, greys and blues of other pelagic cetaceans. The rest of the body's coloration is well demarcated: the chin, throat and belly are white; the flippers, dorsal fin and back are dark grey to black with the exception of the yellow patch; there is a further white patch below the dorsal fin, lying above a light grey stripe that runs from the beak, above the eye and down to the tail stock.

Dolphin group sizes vary by location, with groups averaging 60 in number close to the Newfoundland shores, but rather smaller east of Iceland. From the analysis of the stomach contents of stranded animals, fish such as herring and mackerel and squid appear to form the species' main diet. The Atlantic White-sided Dolphin is fairly acrobatic and keen to interact with boatsWhale and Dolphin Conservation Society - [http://www.wdcs.org/dan/publishing.nsf/allweb/C210381F636070C1802569D00039DC76 Atlantic white-sided dolphin] ] , however it is not as wildly gregarious as the White-beaked and Common Dolphins.

Population and distribution

The species is endemic to the North Atlantic Ocean. Areas of particularly high population density include the shores of Newfoundland and Cape Cod, the triangular area of sea between the United Kingdom, Iceland and Greenland and the North Sea. The total population is believed to be 200-300,000 individuals.

Human interaction

Historically, Atlantic White-sided Dolphins were killed in drives conducted from Norway and Newfoundland. These have ceased in recent years, although they still occur to a lesser extent from the Faroe Islands, where the meat and blubber are in high regard as food. [ [http://www.tinganes.fo/ew/media/Til%20enskan%20tekst/Update%20June%202003.doc UMSITINGEN: 10JUNR2003 report by the Faroe Islands' Prime Minister's Office, entitled: "WHALES & WHALING IN THE FAROE ISLANDS"] ]

Reported catches in the years from 1995 to 1998 were 157, 152, 350, and 438, respectively (Bloch and Olsen 1998, 1999; Bloch et al. 1997, 2000). In 2002, the number reported killed was 774. [ [http://www.tinganes.fo/ew/media/Til%20enskan%20tekst/Update%20June%202003.doc UMSITINGEN: 10JUNR2003 report by the Faroe Islands' Prime Minister's Office, entitled: "WHALES & WHALING IN THE FAROE ISLANDS"] ]

References

* Database entry includes justification for why this species is of least concern
*"Atlantic White-sided Dolphin" by Frank Cipriano, "Encyclopedia of Marine Mammals" pp49-51 ISBN 0-12-551340-2
*"National Audubon Society: Guide to Marine Mammals of the World" ISBN 0-375-41141-0
*"Encyclopedia of Marine Mammals" ISBN 0-12-551340-2

External links

* [http://www.wdcs.org: Whale and Dolphin Conservation Society]
* [http://www.arkive.org/species/ARK/mammals/Lagenorhynchus_acutus/ Atlantic White-sided Dolphin] at ARKive