CNBNews Hunting and Fishing: Walking Catfish Have Invaded the United States
Monday, November 26, 2012
The Walking catfish, Clarias batrachus, also known as the Magur or Pla Duk Dam, is a species of air breathing catfish with the ability to “walk” out of the water and across land. Its “walk” is more like a sort of wriggling motion with snakelike movements, as well as using its pectoral fins as “legs”. This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams and rivers (Mekong and Chao Phraya basins), flooded rice paddies or temporary pools which may dry up. When this happens, its “walking” skill comes in handy for moving to other sources of water. In Tamil it is known as keluthi or keluthu.
Walking catfish are around 11.81 in (30 cm) in length and have an elongated body shape. This catfish has long-based dorsal and anal fins as well as several pairs of sensory barbels. The skin is scaleless but covered with mucus, which protects the fish when it is out of water.
In the wild, the natural diet of this creature is omnivorous; it feeds on smaller fish, mollusks and other invertebrates as well as detritus and aquatic weeds. It is a voracious eater which consumes food rapidly and this habit makes it a particularly harmful invasive species.
The walking catfish is a native of South East Asia including Thailand, eastern India, Sri Lanka, Bangladesh, Burma, Indonesia, Singapore, and Borneo. It was probably introduced into the Philippines. The catfish is a tropical animal and prefers a water temperature in the range of 50 ““ 82.4Â°F (10 – 28Â°C).
In the United States it is a non-indigenous invasive species, which is now established in Florida and reported from California, Connecticut, Georgia, Massachusetts, and Nevada.
The walking catfish was imported to Florida, reportedly from Thailand, in the early 1960s for the aquarium trade. The first introductions apparently occurred in the mid-1960s when adult fish imported as brood stock escaped, either from a fish farm in northeastern Broward County or from a truck transporting brood fish between Dade and Broward counties. Additional introductions in Florida, supposedly purposeful releases, were made by fish farmers in the Tampa Bay area, Hillsborough County in late 1967 or early 1968, after the state banned the importation and possession of walking catfish.
Aquarium releases likely are responsible for introductions in other states. Dill and Cordone (1997) reported that this species has been sold by tropical fish dealers in California for some time.
In Florida, walking catfish are known to have invaded aquaculture farms, entering ponds where these predators prey on fish stocks. In response, fish farmers have had to erect protective fences to protect ponds. Authorities have also created laws that banned possession of Walking Catfish.