A Study on the World's Biggest Fish: The Whale Shark

A Study on the World's Biggest Fish: The Whale Shark
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The Whale Shark

The whale shark is the only living member of its genus, Rhincodon. This gentle giant is a filter feeder that grows to a documented 41.5 feet in length and 75,000lbs. Although this is the largest scientifically documented whale shark there are several reports of fish reaching upwards of 65 feet with weights nearing 90,000lbs. To put this in perspective the second largest fish is a basking shark 40 feet and 8,000 pounds.

The unique yellow spotted pattern on the grey fish gives it the look of a clear night sky and several indigenous populations throughout the tropical range of the whale shark have names for it that reflect this. In Madagascar the whale shark is called “marokintana” meaning “many stars.” In Java the whale shark also evokes the stars. They call it “geger lintang,” which means “stars in the back.”

What Does a Huge Fish Eat?

The whale shark is a filter feeder although it does have 300 to 350 rows of small teeth. These teeth may be used for eating small fish but most scientists believe they are a remnant of evolution serving little purpose to the current shark. Like other large marine animals, specifically baleen whales, the whale shark filters macro algae, plankton and krill through its gill system by gulping in large amount of water and straining the small creatures in a mesh-like area in the mouth. They were once thought to be strictly filter feeders until a British expedition caught a large whale shark on tape feeding on small schooling fish. It has since been determined that they also feed on small squid as well.

Fish Stories

The largest documented whale shark ever was caught on November 11, 1947. Fishermen near Baba Island, Pakistan spent three hours dragging it back to shore where it was measured at 41 ½ ft. long and 23 ft. wide. The weight was taken on a commercial fish scale and came out to just over 47,000 lb.

Even though the Baba Island whale shark is the largest documented fish, there are several accounts of gigantic whale sharks being observed or even caught but none of these have sufficient documentation for the claims to be authenticated. Still, there is no reason to believe that creatures of the reports sizes don’t exist. The ocean is largely unexplored and with diving depths recorded as deep as 2300 ft. the largest of the whale sharks may simply be swimming in places we haven’t yet looked.

Edward Perceval Wright, while studying the species in 1868 near the Republic of Seychelles, claimed to have witnessed individual sharks approximately 50 ft long and relayed accounts by locals of some that were almost 70 ft in length.

Hugh M. Smith published a firsthand account of a huge fish caught in a bamboo trap in Thailand in 1919. This 1925 account stated that “the shark was too heavy to pull ashore, but Smith estimated that the shark was at least 56 ft long and weighed approximately 82,000 lb.

The 1934 account of a whale shark encounter with a ship named the Maurguani in the Southern Pacific Ocean tells of the ramming of the fish and its subsequent trouble as the fish became caught in the prow. The account claimed that 15 ft were visible on one side of the ship with 40 ft. more on the other.

The whale shark may be a living relic from a time when large filter feeders were kings of the sea. Once endangered due to commercial fishing it now thrives with sightings increasing every year. The Shark Trust and Project AWARE work with Whalesharkproject.org to foster preservation of this species by promoting underwater swims with the gentle giants. The website is full of user submitted images that show the world’s biggest fish in all its immense glory.


Wood, Gerald L., Animal Facts and Feats, Sterling Publishing, 1990

Maniguet, Xavier, Jaws of Death:Sharks as Predator, Man as Prey; HarperCollins, 1991

Whale Shark Project, https://www.whalesharkproject.org/

Image courtesy of Ravas51 at FlickR