posts tagged "sharks"
Whale Sharks are slow moving filter feeding sharks, the largest living fish species. The heaviest Whale Shark ever recorded was 36 tonnes (79,000 lb), but there have been unconfirmed reports of larger Whale Sharks. The Whale Shark is found in tropical and warm oceans, they are known to migrate every spring to the continental shelf of the central west coast of Australia.
Although whale sharks have very large mouths, they feed mainly, though not exclusively, on plankton, microscopic plants and animals, although the BBC program Planet Earth filmed a whale shark feeding on a school of small fish. The Whale Sharks mouth can contain between 300 and 350 rows of teeth, and has 5 large pairs of gills.
The Whale Shark mainly feeds on macro-algae, plankton, krill, Christmas Island red crab larvae and small nektonic life such as small squid or vertebrates. The many rows of teeth play no role in feeding; in fact, they are reduced in size in the whale shark. Instead, the shark sucks in a mouthful of water, closes its mouth and expels the water through its gills. During the slight delay between closing the mouth and opening the gill flaps, plankton is trapped against the dermal denticles which line its gill plates and pharynx. This fine sieve-like apparatus, which is a unique modification of the gill rakers, prevents the passage of anything but fluid out through the gills, trapping anything above 2 to 3 millimetres (0.079 to 0.12 in) in diameter. Material caught in the filter between the gill bars is swallowed. 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. Whale sharks migrate to feed and possibly to breed.
Habitat: Tropical and warm temperature oceans
Food: Plankton, macro-algae, krill, christmas island red crab, squids and vertebrates.
Life Span: 70 Years
Status: Vulnerable
Breeding: Litters have varied from 20 pups to 100
