Lifespan, longevity, and ageing
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Observations: In one study in the wild, of ten specimens caught, the oldest was estimated to be 16 years old (Jefferson and Leatherwood 1994). Maximum longevity is unknown.
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Trophic Strategy
provided by Animal Diversity Web
Fraser's dolphins primarily eat fish, but they also feed on squid, cuttlefish and shrimp. There is strong evidence that these animals prefer to feed at depths of 250-500 meters and rarely at the surface.
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Morphology
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Other Physical Features: endothermic ; bilateral symmetry
Average mass: 164000 g.
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Distribution
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These dolphins are restricted to tropical and subtropical waters.
Biogeographic Regions: indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Benefits
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People in many Asian cultures hunt this species for food.
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Benefits
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Because they do not feed at the surface, they do not compete with fisherman for tuna or other pelagic fish.
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Conservation Status
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CITES Appendix 2
IUCN Red List of Threatened Species: least concern
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Behavior
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Perception Channels: tactile ; chemical
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Reproduction
provided by Animal Diversity Web
Breeding appears to be year-round with a possible peak in the summer months. The gestation period is thought to be about 11 months. Sexual maturity of both sexes occurs at about seven years of age. There is no sexual dimorphism except in the size and shape of the dorsal-fin, with male fins being larger than female fins.
Breeding season: Breeding appears to be year-round with a possible peak in the summer months.
Average gestation period: 11 months.
Average age at sexual or reproductive maturity (female): 7 years.
Average age at sexual or reproductive maturity (male): 7 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average gestation period: 335 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (female)
Sex: female: 2646 days.
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- Weinstein, B. 1999. "Lagenodelphis hosei" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lagenodelphis_hosei.html
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- Bret Weinstein, University of Michigan-Ann Arbor
Biology
provided by Arkive
The preference of Fraser's dolphin for deep waters is due to the prey on which it feeds; fish, squid and crustacean species that inhabit the deeper waters of the oceans. Feeding on such food requires Fraser's dolphin to dive down to depths of at least 250 to 500 metres to hunt. It is thought that Fraser's dolphin itself may be occasional prey for killer whales, false killer whales and large sharks, and circular wounds caused by the peculiar cookie-cutter shark (Isistius brasiliensis) have been found on this species (2) (3).
Fraser's dolphins are highly sociable mammals that swim around in tightly-bonded schools of 100 to 1,000 individuals (2) (6), often together with schools of melon-headed whales (Peponocephala electra), other dolphin species (2) (3), or in some areas, such as the Sulu Sea, with short-finned pilot whales (Globicephala macrorhynchus) (7). A school of Fraser's dolphins moves quickly, on very rare occasions riding the bow waves of boats, and with members of the school frequently porpoising; the term used to describe a dolphin leaping clear of the water when surfacing to breathe (2) (3).
Mating in Fraser's dolphin is believed to be promiscuous, and mature females give birth approximately every two years to a metre-long calf, after a gestation period of 12.5 months. Males reach sexual maturity at an age of seven to ten years, while females are able to reproduce at five to eight years of age (2).
Conservation
provided by Arkive
The south-east Asian populations of Fraser's dolphin are listed on Appendix II of the Convention on Migratory Species (CMS), meaning that this species would significantly benefit from international cooperation. CMS encourages the range states to develop agreements that will benefit the conservation of this species (9). In 1992, the Department of Agriculture of the Philippines banned the 'taking or catching, selling, purchasing, possessing, transporting and exporting of dolphins'. This order has not stopped dolphin hunting, but seems to have decreased the sale of dolphin meat openly in the market (8). The distribution, migratory behaviour, abundance and by-catch rates of Fraser's dolphin are poorly known (8), and thus further research into this sociable dolphin is likely to be the first step in the development of any conservation measures.
Description
provided by Arkive
This tropical dolphin was scientifically described in 1956 from an individual washed up on a beach in Borneo (2), but was not actually recorded alive until the 1970s (5). Fraser's dolphin can be identified by its stocky body and short beak, and by its small flippers, tail fin and triangular or slightly curved dorsal fin. The body bears a striking colour pattern, but one that varies with both age and sex. The back is brownish-grey, the lower sides of the body cream-coloured, and the belly is white or pink. A prominent black stripe runs along the side of the body from the eye to the anus; in adult males this is thick, while in adult females it is variable and in young dolphins the stripe is faint or completely absent. The same pattern occurs with a black stripe on the face; this is absent in calves and variable in females, while on adult males it is extensive and merges with the body stripe to form a 'bandit mask' (2).
Habitat
provided by Arkive
Inhabits deep, oceanic waters except in places where deep water approaches the coast, such as in the Philippines and Indonesia (2).
Range
provided by Arkive
Fraser's dolphin is a tropical species distributed in oceans between latitudes of 30°N and 30°S (2).
Status
provided by Arkive
Classified as Least Concern (LC) on the IUCN Red List (1), and listed on Appendix II of CITES (4).
Threats
provided by Arkive
While poorly-known, Fraser's dolphin is believed to be reasonably abundant due to the incredibly large schools that have been observed (1). In certain areas, however, it remains vulnerable to the threat of hunting and by-catch. In the lower Antilles, Indonesia and (before its protection) the Philippines, this species has been killed by harpoon and its meat consumed or sold in local markets. Some are also taken in fisheries in Taiwan and Japan, and in many areas Fraser's dolphin is caught unintentionally in fishing gear (2) (8).
Diagnostic Description
provided by FAO species catalogs
For a decade and half, this species was known only from skeletal material, until it was "rediscovered" in the early 1970's. It is a distinctive dolphin, with a stocky body and extremely small appendages. The short dorsal fin is triangular or slightly falcate. There is a very stubby, but well-defined, beak. The colour pattern is striking; the most distinctive feature is a dark band of varying thickness, running from the face to the anus (in some regions, the band is indistinct). This band is scarcely apparent on young animals, and appears to widen and darken with age in some animals. There is also a flipper stripe that starts at midlength along the lower jaw (in some animals the side stripe is so wide that it merges with the flipper stripe, creating a dark face mask). Otherwise, the back is dark brownish grey, the lower sides are cream coloured, and the belly is white or pink. Young animals in particular may have pinkish bellies. There are 38 to 44 pairs of sharp teeth in each jaw. Can be confused with: The unique body shape of Fraser's dolphin should rule-out confusion with other species, but striped dolphins which also have an eye-to-anus stripe, can be confused with Fraser's at a distance.
- bibliographic citation
- Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. .
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- Food and Agriculture Organization of the UN
Size
provided by FAO species catalogs
Maximum size is at least 2.7 m. They may reach weights of over 210 kg. Newborns are less than 1 m long.
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- Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. .
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- Food and Agriculture Organization of the UN
Brief Summary
provided by FAO species catalogs
There is little known of this tropical and subtropical species. Herds tend to be large, consisting of hundreds or even thousands of dolphins, often mixed with other species, especially melon-headed whales in the eastern tropical Pacific, Philippines and Gulf of Mexico, and Risso's dolphins and spinner dolphins in the Philippines. In some areas, it is considered shy and difficult to approach; in others it is a bit more approachable. It does not bowride in the eastern tropical Pacific, but it does in most other areas. Running herds create a great deal of white water. There is not much known of reproductive biology. Fraser's dolphins appear to feed on mid-water fish, squid, and crustaceans.
- bibliographic citation
- Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. .
- author
- Food and Agriculture Organization of the UN
Benefits
provided by FAO species catalogs
Catches in various fisheries throughout the range are known; however, none appear to be seriously affecting numbers. A few have been captured live and some killed in harpoon and net fisheries in the Philippines. They are occasionally taken in the Japanese drive fishery, and some are taken in Sri Lanka, the Caribbean, and Indonesia. IUCN: Insufficiently known.
- bibliographic citation
- Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. .
- author
- Food and Agriculture Organization of the UN
Fraser's dolphin
provided by wikipedia EN
Fraser's dolphin or the Sarawak dolphin (Lagenodelphis hosei) 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.
Taxonomy
Lagenodelphis hosei is species of the delphinid family, distinguished from other dolphins as a monotypic genus, Lagenodelphis.[4]
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[3][5] 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) by adulthood. They have a stocky build, a small fin in relation to the size of the body, as well as conspicuously small flippers. The dorsal fin and beak are also shorter than other species of dolphin. 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 this 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, numbering anywhere from 100 to 1,000 in number. Often porpoising, the groups chop up the water tremendously. The sight of seeing a large group fleeing from a fishing vessel has been reported as "very dramatic".
It is also unique in 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.
The Philippines is particularly known area for dolphin sightings, and is home to one of the larger populations of the Fraser's dolphin in the world.
Conservation
The Southeast Asian populations of Fraser's dolphins are listed on Appendix II [6] of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), since they have an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.[7]
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)[8] and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU).[9]
See also
Footnotes
References
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^ Kiszka, J.; Braulik, G. (2018). "Lagenodelphis hosei". IUCN Red List of Threatened Species. 2018: e.T11140A50360282. doi:10.2305/IUCN.UK.2018-2.RLTS.T11140A50360282.en. Retrieved 19 November 2021.
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^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
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^ a b Lagenodelphis hosei Fraser, F.C. 1956. A new Sarawak dolphin. Sarawak Museum Journal 7(8, ns): 478-503 [478].
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^ Hershkovitz, P. (1966). "Catalog of living whales". Bulletin of the United States National Museum (246): viii 1-259 [60]. doi:10.5479/si.03629236.246.
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^ Marshall, N. B. (1979). "Francis Charles Fraser. 16 June 1903-21 October 1978". Biographical Memoirs of Fellows of the Royal Society. 25: 287–317. doi:10.1098/rsbm.1979.0010. S2CID 71184662.
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^ "Appendix II Archived 11 June 2011 at the Wayback Machine" 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.
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^ "Convention on Migratory Species page on the Fraser's dolphin". Archived from the original on 15 October 2012. Retrieved 31 August 2011.
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^ Pacific Cetaceans MoU
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^ Western African Aquatic Mammals MoU
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Fraser's dolphin: Brief Summary
provided by wikipedia EN
Fraser's dolphin or the Sarawak dolphin (Lagenodelphis hosei) 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.
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Distribution
provided by World Register of Marine Species
pantropical
van der Land, J. (ed). (2008). UNESCO-IOC Register of Marine Organisms (URMO).
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Habitat
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oceanic
van der Land, J. (ed). (2008). UNESCO-IOC Register of Marine Organisms (URMO).
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IUCN Red List Category
provided by World Register of Marine Species
Least Concern (LC)
IUCN (2008) Cetacean update of the 2008 IUCN Red List of Threatened Species.
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