Several non-native animal species have been brought into Vietnam in recent years, scientists say, warning that a failure to check this could see the invaders displace native species and damage the ecosystem.

Fishermen on the Saigon River have recently caught a lot of suckermouth catfish (Hypostonuns lecostomus) – an imported ornamental fish.

Fisherman Nguyen Van Chuc of Ho Chi Minh City ’s Binh Thanh district said he caught 100 of them daily.

“The fish have been reproducing rapidly and I can now catch them every-where.”

Dr. Nguyen Tuan of the Research Institute for Aquaculture No. 2, said the suckermouth catfish eats indiscriminately and reproduces rapidly.

“To compete for food, the fish invades the environments of other species and damages them,” he said.

Ba Kinh, a fisherman who lives in Ho Chi Minh City’s Thu Duc district, said in the past he could catch 30-35 snake-head fish, catfish, anabas, and shrimps daily in the Saigon River, but now he caught only 10 anabas.

“May be the suckermouth is one of the causes of the disappearance of other fish in the river,” he said.

The suckermouth has also appeared in rivers in the Mekong Delta in recent years.

Two carnivorous fish species, ca chim trang (Colosoma brachpomum) and ca hoang de (Cichla ocellaris), are threatening the ecology of the Tri An Reservoir in the southeastern province of Dong Nai, according to local scientists.

Farmers originally brought the two fish species, which are native to the tropical areas of the Amazon River, and bred them in the reservoir. They are now reproducing rapidly and making short work of their indigenous consins.

Yabby (Cherax destructor), a species of crayfish from Australia, was recently imported and bred by local farmers in the central province of Phu Yen.

Tuan said the yabby is threatening irrigation works because of their habit of burrowing into levee banks and dam walls.

“If farmers let the yabby get out of captivity, they can cause considerable damage to dams on the Red River,” he warned.

Dr. Nguyen Dang Nghia, director of the Agriculture Technology Transfer Centre, said authorities are lax about controlling the entry of non-native species into the country.

Several species had been imported without careful research into their impact on the local ecosystem, he said.

Many animals are also illegally imported into the country.

Phan Van Nghiem, head of the HCM City Department of Health’s Medicine Division, said officials had discovered and destroyed some strange mosquito larvae imported illegally. (VNA)