Catfish, giant

Pangasianodon gigas

phylum: Chordata

class: Osteichthyes

order: Siluriformes

family: Pangasiidae

status: Endangered, IUCN Endangered, ESA

range: Cambodia, China, Laos, Myanmar, Thailand, Vietnam

Description and biology

The giant catfish is one of the largest catfish species in the world. It can grow to almost 10 feet (3 meters) long and weigh up to 660 pounds (300 kilograms). The fish has smooth skin and a short pair of barbels (slender feelers extending from the head near the mouth). Adult giant catfishes lack teeth. It is believed they feed on algae grazed from stones in the riverbed.

Biologists (people who study living organisms) have very little information about the location of spawning (egg-laying) grounds and the reproductive habits of this catfish. Adults are known to migrate upstream in northern Thailand in April and May. The giant catfish is the fastest-growing catfish species and one of the fastest-growing freshwater fishes. Catfish raised in captivity have reached a weight of 220 pounds (100 kilograms) in just 3 years. Biologists believe the fish grows even faster in the wild.

Habitat and current distribution

The giant catfish is found in the Mekong River and its tributaries. Its range in the Mekong extends from the Vietnam-Cambodia border north through Cambodia, along the Thailand-Laos border and the Laos-Myanmar border, into Yunnan Province in China. It occupies the following tributaries of the Mekong: the Tonle River and the Tonle Sap (lake) in Cambodia; the Mun, Songkhram, and Kok rivers in Thailand; and the Yangpi River in China.

Adult giant catfish like to inhabit basins and deep depressions in large rivers in their range.

History and conservation measures

The giant catfish has been hunted for food for centuries. Although commercial fishing of the catfish had declined by the 1950s, it has recently increased.

Despite this increase, fishing is not a major threat to the giant catfish. What endangers this species more is the construction of dams along the Mekong to supply water to growing communities and farms in the region. Dams prevent the catfish from migrating upstream to spawning areas.

To keep the number of giant catfish from declining, the Fisheries Department in Thailand launched a captive-breeding program in 1967. In 1984, 80,000 of these captive-breed giant catfish were released into the Mekong. Two years later, that number increased to 300,000. Still, in 2001, catfish fishery in Thailand collapsed altogether due to the lack of fish. Numbers also dropped rapidly in Cambodia. The International Union for Conservation of Nature and Natural Resources (IUCN) began its process of upgrading the species status to critically endangered. Even so, in December 2003, the species' spawning grounds in the Mekong were due to be dynamited as part of a program of navigation channel improvements planned by the governments of China, Burma, Thailand, and Lao People's Democratic Republic. In the meantime, conservationists in Cambodia and Thailand were conducting migration studies and working with local fishers in order to try to save the giant catfish from extinction.

DID YOU KNOW?

The traditional Thai New Year's celebration, called Songkhran, begins April 13. From this time until the end of May, farmers in the northern regions of Thailand undertake an ancient ritual. They leave their fields and go to the banks of the Mekong River. They take to the waters in long wooden boats and, armed with large nets, seek to catch giant catfish.

Villagers in these northern areas consider the catfish sacred. Before the fishing can begin, rituals must be performed. In ancient times, pig or chicken sacrifices were offered to the Spirit of the Water and the Spirit of the Fish. Boats, nets, and fishermen were all blessed. Celebrations with food, drink, music, and dancing often lasted more than three weeks. Although not so involved as in the past, these sacrifices and celebrations still mark the beginning and end of the fishing season.