The largest of all fishes (Rhincodon typus), widely distributed in surface waters of tropical seas; length up to 18 m/60 ft; weight up to 20 tonnes; feeds mainly on small planktonic organisms. (Family: Rhincodontidae.)
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?Whale shark Conservation status: Vulnerable |
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Whale shark in the Georgia Aquarium. |
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Rhincodon typus (Smith, 1828) |
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Range of whale shark |
| Sharks Portal |
The whale shark, Rhincodon typus, is a gentle and slow filter feeding shark that is the largest living fish species. The name "whale shark" comes from the fish's large size and eating habits; that is, a shark as large as a whale that shares a similar filter feeder eating mode.
Distribution and habitat
The whale shark inhabits the world's tropical and warm-temperate oceans. The whale shark is solitary and rarely seen in groups unless feeding at locations with an abundance of food. These spots are unique to each whale shark and because of this they can be used to identify each animal and hence make an accurate population count. A juvenile whale shark's tail has a larger upper fin than lower fin while the adult tail becomes semi-lunate (or crescent-shaped).
The whale shark is not an efficient swimmer since the entire body is used for swimming, which is unusual for sharks and contributes to an average speed of only around 5 km/h. Perceval Wright spent time in the Seychelles, during which he managed to obtain several small whale shark specimens, but claimed to have observed specimens in excess of 15 m (49 ft), and tells of reports of specimens surpassing 21 m (69 ft). Smith describes a huge whale shark caught in a bamboo fish trap in Thailand in 1919. The shark was too heavy to pull ashore, but Smith estimated that the shark was at least 17 m (55.7 ft) and weighed approximately 37 tonnes (81,500 lb), which have been exaggerated to an accurate measurement of 17.98 m and weight 43 tonnes in recent years. In 1934 a ship named the "Maurguani" came across a whale shark in the Southern Pacific ocean, rammed it, and the shark consequently became stuck on the prow of the ship, supposedly with 4.6 m (15 ft) on one side and 12.2 m (40 ft) on the other.
Diet
The whale shark is a filter feeder - one of only three known filter feeding shark species (along with the basking shark and the megamouth shark). Whale sharks have been observed "coughing" and it is presumed that this is a method of clearing a build up of food particles in the gill rakers. The whale shark is an active feeder and targets concentrations of plankton or fish by olfactory cues rather than simply 'vacuuming' constantly. Whale sharks congregate at reefs off the Belizean Caribbean coast, supplementing their ordinary diet by feeding on the roe of giant cubera snappers, which spawn in these waters between the full and quarter moons of May, June and July, .
The whale shark does not need to swim forward when feeding;
Reproduction
The reproductive habits of the whale shark are obscure.
Conservation status
The whale shark is targeted by artisanal and commercial fisheries in several areas where they seasonally aggregate. Whale sharks are known to frequent the waters off Donsol in the Sorsogon province of the Philippines.
Whale sharks in captivity
A whale shark is featured as the main attraction of Osaka Aquarium Kaiyukan and as of 2005, three whale sharks are being studied in captivity at the Okinawa Churaumi Aquarium in Japan. The two females were added on June 3, 2006 in hopes that reproduction in whale sharks could be studied in captivity.
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