Feeding of Whale Shark
Whale sharks are filter feeders that sieve small animals from the water. As they swim with their mouth open, they scoope masses of water into their mouth and through spongy tissue between their 5 large gill arches. The sharks use gills rakers that filter the nourishment from the water. Anything that does not pass through the gills is eaten and water is expelled through 5 pairs of gill slits. Gill rakers are bristly structures (the thousands of bristles are about 4 inches or 10 cm long) in the sharks's mouth that trap the small organisms. The shark can process over 1500 gallons (6000 liters) of water each hour.
Understanding the whale shark diet is especially important because food sources determine much of its movement and location. Its food list includes the eggs of little tunny (Euthynnusalletteratus), mackerel, sardines, anchovies, copepods (small crustaceans), shrimp, plankton, krill and squid.