Whale Shark
While its name may be deceiving, the whale shark is actually a shark, and the largest fish in the world. Whale sharks can grow to 65 feet in length and up to about 75,000 pounds in weight. Females are generally larger than males.
They are huge and streamlined, and have a beautiful coloration pattern on their back and sides that is made up of light spots and stripes over a dark gray, blue or brown background. They have a white underside.
Like the basking shark, whale sharks feed by filtering small organisms, such as plankton, crustaceans, tiny fish, and occasionally larger fish and squid. Unlike the basking shark, which moves water through its mouth by slowly swimming forward, the whale shark feeds by opening its mouth and sucking in water, which then passes through the gills. Along the way, organisms get trapped in the shark's dermal denticles (small, tooth-like structures) and the pharynx, which is a rake-like structure. A whale shark can filter over 1,500 gallons of water an hour.
Whale sharks are ovoviviparous and females give birth to live young that are about 2 feet long. Their age at sexual maturity and length of gestation is unknown. Not much is known about breeding or birthing grounds either, although in March 2009, a 15-inch long baby whale shark was rescued from a coastal area in the Philippines, where it had been caught in a rope. This may mean that the Philippines is a birthing ground for the species.
Whale sharks appear to be a long-lived animal. Estimates for longevity of whale sharks are in the range of 60-150 years.
The whale shark is listed as vulnerable on the IUCN Red List, because of hunting, its highly migratory nature, impacts of diving tourism and overall low abundance, which make it "vulnerable to exploitation."
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