Environment Southland is investgating the death of a number of eels in the Waihopai River, behind Bill Richardson Drive in Invercargill.

The dead eels were mainly found at the edge of a stormwater outlet yesterday morning and Environment Southland's compliance team has joined Invercargill City Council staff to investigate.

There were no obvious signs of any pollution, but further dead eels were found within the pump chamber. 

Approximately 20 eels were found and Invercargill City Council is carrying out tests on its stormwater network to establish if there are any signs of contamination.

Environment Southland’s compliance team has also taken water samples and some of the eels will be sent away for further testing.

Local Iwi have been notified.