Sim Bak Heng New Straits Times 18 Jan 14;
RIVER THREAT: Unscrupulous importers to blame
JOHOR BARU: ALIEN predator fish are multiplying at such a rapid rate in Malaysian waterways that many indigenous river species have ended up as their meal.
The presence of the predator species, such as the Peacock Bass, Alligator Pike, Arapaima, Amazon Catfish, Armoured Catfish and Tiger Fish, as well as crustacean species, such as the Red Claw Crayfish and Blue Claw Crayfish, are wiping out many river species.
Environmentalists are blaming unscrupulous ornamental fish importers for illegally bringing in the predator species in the form of fish fry. The predator fish, especially the Arapaima and Alligator Pike, are attractive to enthusiasts and sold before they have matured.
Malaysia Nature Society (Johor chapter) chairman Vincent Chow said the problem would start when the predator fish matured and developed a big appetite, which many enthusiasts could not afford to meet.
"When aquarium operators and enthusiasts find it hard to maintain the fish, which can grow up to 2m long, they release the fish into rivers or ponds, where they breed rapidly. This is when the buffet-style feasting begins."
Chow said most rivers in the state that flowed through urban areas, including Sungai Skudai, Sungai Mengkibol and Sungai Kahang, were contaminated with predator fish and crustaceans.
"The Armoured Catfish, Tilapia, Red Claw Crayfish and Blue Claw Crayfish are the major predator species found in the rivers. These species are becoming the dominant ones, upsetting the food chain and ecosystem."
He cited the example of the Snakehead species, which was introduced in Florida, the United States, years ago. The fish multiplied so rapidly that the species became unmanageable, with reports of even humans having been attacked by them.
Some species also dig tunnels in riverbanks to lay eggs, causing some stretches to collapse.
Chow said the Armoured Catfish and the two crustacean species were the main culprits in destabilising riverbanks.
He called on the Fisheries Department to enforce the law in dealing with those found to be importing, selling and keeping alien predator fish.
