Delphinus capensis, Gray, 1828
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publication ID |
https://doi.org/ 10.5281/zenodo.6610922 |
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DOI |
https://doi.org/10.5281/zenodo.6608642 |
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persistent identifier |
https://treatment.plazi.org/id/BD4CCC61-7621-FFE9-FF7B-FA9AE151F7EB |
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treatment provided by |
Diego |
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scientific name |
Delphinus capensis |
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11. View On
Long-beaked Common Dolphin
Delphinus capensis View in CoL
French: Dauphin du Cap / German: Langschnauzendelfin / Spanish: Delfin de hocico largo
Other common names: Cape Dolphin, Long-beaked Saddleback Dolphin; Indo-Pacific Common Dolphin (tropicalis)
Taxonomy. Delphinus capensis Gray, 1828 View in CoL ,
Cape of Good Hope.
Only a single species of common dolphin was recognized before 1994 when it was splitinto D. delphis and D. capensis . Taxonomy of D. capensis is uncertain. Difficulties in distinguishing D. capensis from D. delphis in regions where they are sympatric and more recent genetic work have called into question monophyly of D. capensis , which may have arisen independently in several oceans. The genus Delphinus may thus contain more than two species. A distinct geographical subspecies, the “Indo-Pacific Common Dolphin” (D. c. tropicalis), with a very long beak occurs in the Indo-Pacific Ocean; it was once classified as a separate species. Two subspecies recognized.
Subspecies and Distribution. D.c.capensisGray,1828—distinctpopulationsalongWcoastofNorthandSouthAmerica,theEcoastofSouthAmerica,WAfrica,andtheWPacificOceanfromSJapanandKoreatoNTaiwanandinNewZealand.
D. c. tropicalis van Bree, 1971 — coastal Indo-Pacific Ocean from E & S Africa to S China and W Taiwan, including Red Sea, Persian Gulf, and Gulf of Thailand. View Figure
Descriptive notes. Total length 202-260 cm (males) and 193-222 cm (females); weight up to 235 kg. The Long-beaked Common Dolphin is similar in appearance to the Short-beaked Common Dolphin ( D. delphis ), but it has slightly more slender build and longer beak, and its melon slopesless steeply. Dorsal fin is moderately tall and falcate, with pointed tip, and flippers are small and slender,also with pointed tips. Some adult Long-beaked Common Dolphins,likely males, possess post-anal protrusion. Color pattern is similar to that of the Short-beaked Common Dolphin, with dark-gray dorsal surface, white belly, and hourglass pattern on flanks. Thoracic portion of hourglass tends to be darker and more muted than on the Short-beaked Common Dolphin. There is also distinct dark stripe running from flipper to anus—a feature that tends to be faint or absent in the Short-beaked Common Dolphin. More of beak is black on the Long-beaked Common Dolphin, and dark eye patches may be continuous with flipper-anus stripe. Dorsal fin and flippers tend to be dark, occasionally with faint pale central patches. The Indo-Pacific Common Dolphin has longer beak (9-4-9-7% of body length) than the nominate subspecies (6-:9-7-6% of body length), and as such,it also has a larger tooth count: 54-67 pairs in upperjaw and 52-64 in lowerjaw vs. 47-60 pairs in upper jaw and 48-57 in lower jaw for the nominate subspecies.
Habitat. Coastally distributed, usually within 180 km of shore, and preferring shallow, warm water less than 180 m deep, but not found around oceanic islands distant from continental mainland.
Food and Feeding. Little is known about the diet of the LLong-beaked Common Dolphin, and available data comes from only a few populations. Off Brazil, it prefers cephalopods, but off southern California, Pacific American pilchard ( Sardinops caerulea), northern anchovy ( Engraulis mordax), Pacific saury ( Cololabis saira), Pacific bonito ( Sarda chiliensis), and California market squid ( Doryteuthis opalescens) are preferred. Off South Africa, dominant prey includes South African pilchard ( Sardinops sagax ocellatus) and South African anchovy ( Engraulis capensis ). Cooperative herding of fish schools has been observed in the northern Gulf of California.
Breeding. Very little known is known aboutlife history and reproductive biology of the Long-beaked Common Dolphin. Sexual maturity is thought to occur when individuals are ¢.200 cm in length. Because of its more tropical distribution, the LLong-beaked Common Dolphin likely has less breeding seasonality than does the Short-beaked Common Dolphin.
Activity patterns. Like the Short-beaked Common Dolphin, the L.ong-beaked Common Dolphin is also known to be aerially active in large groups, frequently breaching while traveling, and it is known to readily bow-ride vessels.
Movements, Home range and Social organization. Group sizes of the Long-beaked Common Dolphin are less than twelve to more than 1000 individuals. Social segregation by sex and age classes is suspected and thought to be similar to the Short-beaked Common Dolphin. Little is known about movements and home ranges of populations of Long-beaked Common Dolphins. In South African waters, LLong-beaked Common Dolphins are known to seasonally follow migrating sardines.
Status and Conservation. CITES Appendix II. Classified as Data Deficient on The IUCN Red List. The Indo-Pacific Common Dolphin has not been assessed independently. There are currently no estimates of global abundance for the Long-beaked Common Dolphin, but there are several regional abundance estimates. There are ¢.55,000 individuals off Pacific Mexico, ¢.69,000 individuals in the Gulf of California, and ¢.15,000-20,000 individuals off South Africa. A recent abundance estimate for the Long-beaked Common Dolphin off California is 183,396 individuals—higher than previous estimates. The Long-beaked Common Dolphin is classified as Data Deficient due to unknown severity of direct and incidental catch off West Africa, East Asia, and South America; it is occasionally taken as direct catch. They are taken by harpoon off Margarita Island in eastern Venezuela and occasionally in Japanese drive fisheries. They are also taken opportunistically off north-eastern Taiwan and incidentally in Taiwanese oceanic driftnets. Observed lesions and scars on LLong-beaked Common Dolphins from bycatch indicate that there are violent interactions with fisheries off Peru. It is frequently caught in purse-seine fisheries there, although catch rates have diminished since 1994. They are only rarely caught incidentally in tuna purse-seine fisheries in the tropical Pacific Ocean and not to the same extent as the Short-beaked Common Dolphin. They are also occasionally caught in driftnet fisheries for broadbill swordfish (Xiphia gladius) and common thresher shark (Alopias vulpinus) off California and in gillnet, trawl, and purse-seine fisheries in Indian and Chinese waters. Marine pollution may also be a threat to the LLong-beaked Common Dolphin in some areas. High organochlorine concentrations (primarily DDT and PCBs) have been found in blubber of Long-beaked Common Dolphins caught in Brazilian waters. These contaminants likely come from heavily industrialized areas along the Brazilian coast. High concentrations of heavy metals, primarily zinc, cadmium, and mercury, have also been found in livers and kidneys of Long-beaked Common Dolphins in the Sea ofJapan off South Korea.
Bibliography. Amaral et al. (2012), Carretta, Chivers & Perryman (2011), Carretta, Price et al. (2004), Hammond et al. (2008h), Heyning & Perrin (1994), Jefferson & Van Waerebeek (2002), Jefferson et al. (2008), Kajiwara et al. (2004), Kim Seong-Gil et al. (2011), Kingston & Rosel (2004), Natoli et al. (2006), Perrin (2009d), Santos et al. (2002), Van Bressem etal. (2006).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
