The largest living fish, the whale shark (Rhincodon typus) is a huge carpet shark which cruises through tropical oceans around the world, feeding on plankton and small fish. On average, whale sharks reach 10 metres in length and weigh around 10 tonnes, however, the largest specimen discovered weighed 21.5 tonnes and was 12.65 metres in length (the equivalent weight and length of a fully-loaded bus)! They are grey in colour with a white belly; each individual also has a unique pattern of white spots. Like most sharks, they have two pectoral fins (side-fins) and two dorsal fins (back-fins).
The whale shark is a truly phenomenal animal and despite their size and intimidating name, they do not pose a threat to us. Rather, they prefer to use their 1.5 metre wide mouth to trap and digest colossal amounts of plankton as they glide through the ocean. They will also feed on clouds of eggs during the mass spawning of fish and corals. Impressively, their mouth can contain up to 350 rows of tiny teeth yet these teeth play no part in the whale shark’s feeding routine – they have become vestigial teeth over the course of evolution.
Unfortunately, this mighty fish is listed as endangered by the IUCN. One of the reasons for this is because hundreds of whale sharks are illegally slaughtered in China every year for their skins, oils and fins; they are also frequently hunted in the Philippines. Additionally, they are threatened by the impacts of fisheries, by-catch losses which reduce their availability of prey, and vessel strikes. Their gestation period is unknown, but their long life-span and late maturation mean that it will be difficult to raise their population numbers.
The whale shark’s huge size, combined with its docile nature and elegance make it almost a ‘shark of contrasts’, and it is this uniqueness which means we should help to protect them. Still very little is known about this species’ reproduction and breeding habits since neither the mating nor pupping of whale sharks has ever been documented, making their conservation all the more necessary.