World Library  
Flag as Inappropriate
Email this Article

Fraser's dolphin

 

Fraser's dolphin

The Fraser's Dolphin
Size compared to an average human
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass: Eutheria
Order: Cetartiodactyla[1]
(unranked): Cetacea
(unranked): Odontoceti
Family: Delphinidae
Genus: Lagenodelphis
Fraser, 1956
Species: L. hosei
Binomial name
Lagenodelphis hosei
Fraser, 1956
Fraser's dolphin range

Fraser's dolphin (Lagenodelphis hosei) or the Sarawak dolphin is a cetacean in the family Delphinidae found in deep waters in the Pacific Ocean and to a lesser extent in the Indian and Atlantic Oceans.

Contents

  • Taxonomy 1
  • Description 2
  • Population and distribution 3
  • Conservation 4
  • See also 5
  • Footnotes 6
  • References 7
  • Further reading 8
  • External Links 9

Taxonomy

In 1895, Charles E. Hose found a skull on a beach in Sarawak, Borneo. He donated it to the British Museum. The skull remained unstudied until 1956 when Francis Fraser[7] examined it and concluded that it was similar to species in both the genera Lagenorhynchus and Delphinus but not the same as either. A new genus was created by simply merging these two names together. The specific name is given in Hose's honour.

It wasn't until 1971 that the whole body of a Fraser's dolphin, as it was by then becoming known, was discovered. At that time washed-up specimens were found on Cocos Island in the eastern Pacific, in South Australia and in South Africa.

Description

Fraser's dolphins are about 1 m (3 ft 3 in) long and 20 kg (44 lb) weight at birth, growing to 2.75 m (9 ft 0 in) and 200 kg (440 lb) at adulthood. They have a stocky build, a small fin in relation to the size of the body, conspicuously small flippers. The dorsal fin and beak are also insubstantial. The upper side is a gray-blue to gray-brown. A dirty cream colored line runs along the flanks from the beak, above the eye, to the anus. There is a dark stripe under this line. The belly and throat are usually white, sometimes tinged pink. The lack of a prominent beak is a distinguishing characteristic of the dolphin. From a distance however it may be confused with the striped dolphin which has a similar coloration and is found in the same regions.

Fraser's dolphins swim quickly in large tightly packed groups of about 100 to 1000 in number. Often porpoising, the group chop up the water tremendously. The sight of seeing a large group fleeing from a fishing vessels has been reported as "very dramatic".

It is also marked by having the smallest genitalia of any open sea dolphin.

The species feeds on pelagic fish, squid and shrimp found some distance below the surface of the water (200 m/660 ft to 500 m/1,600 ft). Virtually no sunlight penetrates this depth, so feeding is carried out using echolocation alone.

Population and distribution

Though only accounted for relatively recently, the number of reported sightings has become substantial — indicating that the species may not be as rare as thought as recently as the 1980s. However the species is still not nearly as well understood as its more coastal cousins. No global population estimates exist.

The dolphin is normally sighted in deep tropical waters; between 30°S and 20°N. The Eastern Pacific is the most reliable site for viewings. Groups of stranded dolphins have been found as far afield as France and Uruguay. However these are regarded as anomalous and possibly due to unusual oceanographic conditions, such as El Niño.

The species is also relatively common in the Gulf of Mexico but less so in the rest of the Atlantic Ocean.

Conservation

The Southeast Asian populations of Fraser's dolphins are listed on Appendix II [8] of the Convention on the Conservation of Migratory Species of Wild Animals (

  • Voices in the Sea - Sounds of the Fraser's Dolphin

External Links

  • Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. (2008). Lagenodelphis hosei. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 26 February 2009. Database entry includes justification for why this species is listed as data deficient
  • Whales Dolphins and Porpoises, Mark Carwardine, Dorling Kindersley Handbooks, ISBN 0-7513-2781-6
  • National Audubon Society Guide to Marine Mammals of the World, Reeves, Stewart, Clapham and Powell, ISBN 0-375-41141-0
  • Malaysian Naturalist, Vol 59/3 - 2006, page 5.

Further reading

  1. ^ Agnarsson, I.; May-Collado, LJ. (2008). "The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide reliable species-level phylogenies". Mol Phylogenet Evol. 48 (3): 964–985.  
  2. ^ Price, SA.; Bininda-Emonds, OR.; Gittleman, JL. (2005). "A complete phylogeny of the whales, dolphins and even-toed hoofed mammals – Cetartiodactyla". Biol Rev Camb Philos Soc. 80 (3): 445–473.  
  3. ^ Montgelard, C.; Catzeflis, FM.; Douzery, E. (1997). "Phylogenetic relationships of artiodactyls and cetaceans as deduced from the comparison of cytochrome b and 12S RNA mitochondrial sequences". Molecular Biology and Evolution 14 (5): 550–559.  
  4. ^ Spaulding, M.; O'Leary, MA.; Gatesy, J. (2009). "Relationships of Cetacea -Artiodactyla- Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution". PLoS ONE 4 (9): e7062.  
  5. ^ Cetacean Species and Taxonomy. iucn-csg.org
  6. ^ "The Society for Marine Mammalogy's Taxonomy Committee List of Species and subspecies".
  7. ^ Marshall, N. B. (1979). " 
  8. ^ "Appendix II" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.
  9. ^ Convention on Migratory Species page on the Fraser's dolphin
  10. ^ Pacific Cetaceans MoU
  11. ^ Western African Aquatic Mammals MoU

References

  1. ^ The use of Order Cetartiodactyla, instead of Cetacea with Suborder Odontoceti, is favored by most evolutionary mammalogists working with molecular data [1][2][3][4] and is supported the IUCN Cetacean Specialist Group[5] and by Taxonomy Committee [6] of the Society for Marine Mammalogy, the largest international association of marine mammal scientists in the world. See Cetartiodactyla and Marine mammal articles for further discussion.

Footnotes

See also

In addition, Fraser's dolphin is covered by Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU)[10] and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macronesia (Western African Aquatic Mammals MoU).[11]

[9]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.