Marine Wildlife Encyclopedia
Whale Shark Rhincodon typus
The whale shark is a graceful, slow-moving giant and the largest fish in the world. At 5 ft (1.5 m) wide, its mouth is large enough to fit a human inside, but it is a harmless filter feeder that eats only plankton and small fish.
To obtain the huge amount of food it needs, it sucks water into its mouth and pumps it out over its gills, where particles of food become trapped by bony projections called gill rakers and are later swallowed.
The whale shark has the thickest skin of any animal, at up to 4 in (10 cm) thick. Prominent ridges run the length of its body, and it has a large, sickle-shaped tail. The pattern of white spots on its back is unique to each shark, enabling scientists, through analysis of photographs, to identify individuals.
While little is known of their ocean travels, satellite tagging has shown that some whale sharks migrate across entire oceans. Whale shark eggs hatch inside the mother, and she gives birth to live young. Whale sharks are killed for their meat and fins (used in soup), although they are legally protected in some countries.
Annual Whale Shark Plankton Feast
Every year, around April, whale sharks migrate to Ningaloo Reef off northwestern Australia for a plankton feast. The plankton explosion results from a simultaneous mass spawning of the reef’s corals, possibly triggered by the full moon.
Threats to Whale Sharks
A majority of whale sharks are caught before they even reach maturity. Their fins fetch a high price in Asian markets, although trade is regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Overfishing is a serious concern as whale shark populations are decreasing in numerous regions and the average size of Australian whale sharks is shrinking.
What Oceana Does to Protect Whale Sharks
Oceana is working internationally to protect and restore shark populations. Through policy, science, legal and communications work, Oceana is pushing for true shark finning bans, species-specific shark management and reduced shark bycatch.