Experts baffled by mystery of Thames walking fish
An unusual “walking fish” found washed up in the Thames estuary thousands of miles from home has left wildlife experts baffled and sparked fears of an invasion of British waterways.
Walking catfish, which are native to South East Asia, have the ability to “walk” over land using their stiff pectoral fins to keep themselves upright. They also have an organ that enables them to breathe air when they are out of the water.
But the UK’s Environmental Agency warned that the creatures pose a threat to native species by competing with them for food and spreading disease and parasites.
Catfish are a growing problem in the wild in the United States, where they have colonised large areas after escaping or being released from fish farms or aquariums since they were first imported to the country from Thailand in the 1960s.
In Florida, fish farmers have been forced to erect fences around their ponds to stop the catfish preying on fish stocks.
London angler Birol Koca, who found the dead fish, said he had called the Environment Agency immediately.
“I spotted the dead fish laying on the shore and instantly recognised it as a catfish,” Koca said. “I knew that these fish should not be in our local rivers so I called the Environment Agency’s 24 hour Incident Line.”
Experts suspect the fish may have been a pet that outgrew its tank and was released into the wild deliberately but they are calling on anglers to be vigilant.
“Non-native fish can pose a significant risk to the local environment. The local angler acted very responsibly,” said Emma Barton, Fisheries Officer for the Environment Agency. “By working with us, they have helped ensure that the Thames and the wider environment is protected. We urge others to do the same.”