Whale Shark Facts
The whale shark (Rhincodon Typus) is the largest fish in the world and is expected to have existed for around 60 million years.
Historically, very little data on whale sharks has ever been collected because it was not considered commercially viable. In recent years this status has changed with the increasing demand for shark products from the Asian market. There are increasing reports of whale sharks being taken for their fins as other species of shark become less abundant. The whale shark is currently classed as vulnerable to extinction by the IUCN.
Despite their visible size, relatively little is known about the populations and reproductive cycle of these giants. Below you will find some interesting whale shark facts:
Distribution and Aggregations
Whale sharks are found in all tropical and warm temperate waters around the world except for the Mediterranean Sea. Most sightings are often of individuals, but in some areas the whale sharks aggregate to feed in their hundreds. Some of the confirmed aggregation sites are:
- Gulf of Tadjoura, Djibuti
- Gulf of Mexico
- Gladden Spit, Belize
- Galapagos Islands
- Gulf of California
- Tofo, Mozambique
- Qatar in the Arabian Gulf
Size and Longevity
The largest individual whale shark ever reported to date was from the Taiwanese fishery in 1987 and was recorded as 20m long and weighing 34 tonnes, whilst the next largest was 18·8m from the Indian fishery in Gujarat. Nobody really knows for sure how long whale sharks live for, but estimates put longevity at between 50 and 100 years.
Reproduction and Growth Rates
Whale sharks are ovoviviparous, which means that they produce eggs that develop inside the mother. The young then hatch out of their eggs while they are inside the mother. The mother later gives birth to them.
The whale shark Rhincodon Typus is one of three species of large sharks (the whale shark, basking shark, and the lesser-known megamouth shark) that are known to target plankton and small nekton as food sources. They are all considered ram filter feeders, filter feeding while swimming forward with mouth open. Unlike basking and megamouth sharks, whale sharks also use a suction filter-feeding mechanism. They feed by remaining stationary, either horizontally or vertically, and open their mouths forcefully, sucking in their prey.
Whale sharks are thought to feed on a wide range of prey including krill, copepods, crab larvae, coral spawn, fish eggs and larger prey such as small fishes and squid.
Whale sharks have around 300 rows of small teeth in each of their jaws but their function is unknown.
How to Identify a Whale Shark
Whale Sharks grow to enormous sizes which makes them very difficult to measure and photograph under water. Each Whale Shark has a unique pattern of spots and the scientists can use these spots to recognize individuals, identify new sharks and track known sharks as they move around the oceans.