NEA detects high salinity levels in Marina South canal, likely cause of mass fish deaths

SINGAPORE: The National Environment Agency (NEA) has attributed the death of hundreds of fish in a canal at Marina South to high salinity levels caused by seawater intrusion during high tide.

The incident, spotted by a passer-by on 4 December, was captured on video by the observer’s husband and later uploaded to the Complaint Singapore Facebook page.

The footage, recorded around 4.30pm, showed dozens of lifeless fish drifting in the water, with some carried along by the current.

The man who filmed the scene remarked on the size of the fish, describing them as “quite large.”

Further along the canal, he discovered an even larger group of dead fish, estimating the number to be in the hundreds.

In the video, he speculated about the cause, asking, “What happened to Singapore’s water?”

The couple did not report the incident to the authorities, as they were only passing by.

Netizens Speculate Causes Behind Fish Deaths

The video sparked online discussions, with netizens offering theories about the mass fish deaths.

Some speculated that pollution or contamination might be the cause, with one commenter questioning whether toxins had been disposed of in the canal.

However, another user dismissed the concerns, claiming the phenomenon was “perfectly normal.”

They explained that the fish were likely freshwater species swept into saltwater when the Marina Barrage dam opened during heavy rainfall.

Unable to tolerate the salinity, the fish would have died as a result.

Meanwhile, another commenter expressed concern about potential pollution and urged authorities to clean the canal to prevent further environmental issues.

NEA Investigation Finds No Pollution

In response, NEA conducted an on-site investigation on 5 December. The agency reported that the canal water appeared clean, with no visible oil sheen, discolouration, or odour.

Officers traced the canal, upstream drains, and surrounding areas but found no evidence of pollution from industries or construction sites.

Water sample tests, however, revealed high salinity levels, which NEA attributed to seawater entering the canal during high tide.

NEA confirmed that its appointed service provider had carried out clean-up operations, removing approximately 200 dead fish from the canal.