For the next few months we’re going to share some facts about the whale sharks every week with you. In this fourth episode we’re talking about the feeding & diet of the whale sharks!
Whale sharks mostly eat planktonic animals (euphausiids, copepods, fish and squid eggs or larvae) though they have also been observed to ingest small fishes like sardines and anchovies.
Whale sharks are able to feed in two different ways, ram filter feeding and suction filter feeding:
Ram filter feeding
This way of feeding involves swimming along with their mouths open and feeding on prey that happen to be caught as water asses through the gill rakers.
Suction filter feeding
Whit this way of feeding the whale shark can actually remain stationary in the water and by opening and closing its mouth can actively suck large quantities of water and prey into its mouth. When the mouth closes, the water is forced out through the filter pads and any prey is sieved out. Suction feeding allows the whale shark to feed on more mobile prey like small fish which would usually be able to escape from a ram filter feeder.
Whale sharks evidently only use the suction method when they are feeding on very high concentrations of prey. Consequently, some think that the sharks might actively search for specific areas or seasonal events where high densities of food are more likely and this might explain why whale shark aggregations are seasonal in most areas. In areas where there is no clear whale shark season (the Maldives) other factors like the lunar cycle might have stronger influences on the number of sharks observed. These are also natural triggers for spawning and plankton blooming events.
Information collected from tagging studies has shown that whale sharks are constantly diving and ascending spending only short periods of time near the surface and diving as deep as 1600 meters, evidently to search for the areas where there are high densities of prey in the water column.
If you are interested in facts about the whale sharks, make sure you read this blog every week. If you want more information and want to get the latest news from EcoColors subscribe to our monthly newsletter!