Hundreds of dead fish found in River Shuttle in Bexley

On Monday, June 21, members of the public reported a large number of fish found dead in the river and called the Environment Agency to investigate.

They found several hundred dead fish, most of which will reportedly now decompose without further damage to the water quality.

Water Quality and Fisheries Officers visited later that morning to investigate, and although there were no obvious signs of pollution present we noted a general discolouration and a recent deposit of silt.

The agency has said that unfortunately, the cause of the deaths still remains unknown.

River Shuttle - Geograph

It is believed that whatever caused the fish mortality is likely to have been flushed downstream and diluted by the time samples were taken.

However, the Environment Agency say they are currently having lab analysis carried out on the river water and the investigation remains open.

Thames Water, who operate the surrounding sewage system, also attended and found nothing wrong with the river water or sewage network, and the water quality is thought to be normal.

A spokesperson for the Environment Agency said: "Following reports received from the public we attended the site on the River Shuttle on 21 June. We found several hundred dead fish.

"On inspection our officers could find no issues with the water quality and Thames Water who also attended, confirmed that there were no problems with the nearby sewer network.

“Unfortunately the source and cause of the fish deaths still remains unknown. We have taken water samples for analysis and our investigation remains open.

"Whatever caused the fish mortality, is likely to have been flushed downstream and diluted. The remaining fish carcasses will decompose naturally without having a negative impact on water quality.

“We would urge anyone seeing signs of fish in distress to call our free, 24-hour incident hotline on 0800 80 70 60.”

The Environment Agency carries out many fish rescue operations, saving thousands of fish in rivers, lakes and streams by using aeration equipment or hydrogen peroxide to restore dissolved oxygen levels, clearing pollution, or in some cases relocating fish when it is possible to do so.

They added that reports of fish in distress often increase in the summer due to natural processes reducing oxygen levels in the water.

Last week there were similar reports of fish in distress on the River Cray near Foots Cray Meadow.

Hot, sunny weather can lead to low flows in rivers, and small still waters are particularly susceptible as ponds and lakes start to warm up.

This leads to a fall in dissolved oxygen which can be damaging or even fatal to fish. It is quite common too for contaminants from the roads, plus organic matter such as leaves, silts, sewage to build up in the drainage network during dry weather.

This can then be flushed into the watercourse during rainfall events having a dramatic but short lived impact on water quality.