KUALA TERENGGANU: First local anglers reported catching the pacu, a fish related to the piranha family, and the African catfish (Clarias gariepinus), then the Chao Phraya high fin catfish (Pangasius sanitwongsei), the peacock bass, a carnivorous genus of large cichlids, and the gargantuan redtail catfish (Phractocephalus hemioliopterus) were caught in the country’s rivers, lakes and dams.
Now, anglers have reported landing fish belonging to two new foreign carnivorous species – a cichlid known as the earth eater (Geophagus steindachneri) and the black ghost knifefish (Apteronotus albifrons).
The earth eater has been caught in the Timah Tasoh dam in Perlis, and in Selangor and Johor. It has a life span of up to five years and its menu includes tiny crustaceans, insects and larvae.
A native of South America, the carnivorous black ghost knifefish produces weak electrical impulses.
It has been found in rivers in Kedah, Perak and Selangor.
Universiti Malaysia Terengganu ichthyologist Dr Amiruddin Ahmad, who identified both species through photographs posted on Facebook, said irresponsible aquarists were releasing foreign fish into local rivers.
“When they are young these fish make great pets, but when they become unmanageable, hobbyists tend to release them into rivers. This is when the problem starts,” he told the New Straits Times in an exclusive interview.
“Once a fish is released into the river, it is impossible to remove it. It is a recipe for disaster if more than one fish belonging to the same alien species is released because they can spawn. Our river habitats are not dissimilar to the ecosystems of rivers in the Amazon.”
Amirrudin noted that experts had warned, time and again, about the potential ecological disasters that could result from the introduction of foreign invasive and predatory aquatic life, but they were still being brought into the country.
“Species like the peacock bass, redtail catfish, African catfish and the Chao Phraya high fin catfish were probably released by anglers into local rivers as game fish because they can grow to enormous sizes.
“But, they fail to see that big fish have big appetites. In the end, indigenous species, including our ferocious toman (giant snakehead) could disappear from their natural habitats. Local fish cannot compete with the Amazon giants.”
He said there could be grave repercussions for traditional riverine fishermen as these alien invaders did not have much value as food fish in Malaysia.
He said, the authorities should step in to protect the country’s freshwater fishery heritage and resources before it was too late.