The biggest salt water fish is the whale shark. The biggest specimen was captured November 11, 1947 close to Baba Island, Karachi, Pakistan. It registered a weight of 21.5 tons (47,000 lbs). The shark was 12.65 meters (41.50 ft) long. The girth was measured at 7 meters (23.0 ft).
The whale shark has a large mouth, which can extend up to 1.5 meters (4.9 ft) wide. These may contain up to 350 rows of teeth. Its eyes are set toward the front of the head. The creature has five huge pairs of gills.
The world’s biggest salt water fish has a white belly, but most of the body is grey. There are ridges along the animal’s side. There are checkerboard yellow spots and stripes on the skin. These are unique for each individual.
The skin can be 4 inches (10 cm) thick. The creature also has pectoral fins and a pair of dorsal fins. Younger whale sharks have large fins. The spiracles are to the rear of its eyes.
The whale shark feeds primarily on plankton. It also feeds on Christmas Island red crab larvae, krill and macro-algae. The creature is known as an active feeder. This in direct contrast to the basking shark which is a passive feeder.
Habitat and Distribution
The whale shark can be found in warm temperate and tropical waters. These creatures migrate every spring to the west of Australia’s continental shelf. There, the creatures feed on the plankton at the Ningaloo Reef.
Whale sharks are mostly pelagic. Most are seen offshore, but some have been found near the land. Some specimens have been seen near coral reefs and lagoons. Some of them have been seen at the mouths of rivers and estuaries.
Their movement is limited to about 430 degrees latitude. They are capable of diving to depths of 700 meters (2,300 ft). In spite of their size, these creatures are gentle. Divers can swim beside them without getting hurt. They have been known to play with divers and even let them ride on their backs.
There are stories of even larger whale sharks. Some fishermen have reported seeing specimens 18 meters (59 ft) long.
A 1925 report claims a whale shark was caught in a bamboo trap in 1919. It was 17 meters (56 ft) long and 37 tons (82,000 lbs). No evidence for these claims so the one caught off Karachi is still the biggest salt water fish.