Local fish species under threat

I am a regular visitor to Sungei Punggol, which flows into Punggol Reservoir, and Sungei Seletar, which flows into Nee Soon Swamp and Lower Seletar.

I must commend the National Environment Agency for doing a great job in maintaining these river systems. The water is so clear, you can see right through to the riverbed.

However, I am very concerned about the type of fishes I saw in both rivers.

At Sungei Punggol, I saw many giant snakeheads and a couple of tilapias.

At Sungei Seletar, I saw giant snakeheads, peacock bass, thread-finned acaras and some other unidentified cichlids, probably from the aquarium trade.

All the fish listed are invasive alien species. What is strikingly missing is the lack of small prey.

In a healthy river system, you will see thousands of small prey fish and a few predator fish. However, in both rivers, all I have seen are invasive predator species.

The biggest threat is the presence of giant snakeheads in our rivers.

I believe the snakeheads' invasion of Sungei Punggol has reached a critical stage where most local species have been preyed upon to the point of extinction.

I have also noticed a lack of fishing birds like egrets and herons around the rivers.

I hope the authorities can take action before all our local fish species are hunted to extinction.

The threat is very real as Sungei Seletar flows into Nee Soon Swamp, where the majority of our local fish species can be found.

Perhaps the authorities could organise controlled fishing competitions targeting snakeheads and peacock bass to help reduce their populations.

Kan Shik Kiong

A version of this article appeared in the print edition of The Straits Times on August 10, 2015, with the headline 'Local fish species under threat'. Print Edition | Subscribe