Fish deaths in Otago remain a mystery after new report inconclusive

The deaths of hundreds of fish in a Kaikorai stream remain unexplained, after a new report found there was no strong evidence to blame the regional council.
Hundreds of dead smelt, flounder, bullies, trout and inanga (whitebait) were found littering the shore of the Otago stream last month.

The Otago Regional Council, which manages the waterway, promised it would investigate what led to the deaths, but water samples released last week found no conclusive evidence of pollution from upstream.

However, the samples suggested the councils opening of the coastal mouth at the nearby estuary on the same weekend the fish died was a possible factor.

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A new report has found there was no strong evidence to link the opening of the coastal mouth to the fish deaths, despite the opening's timing suggesting it played a role.

Hamish McNeilly/Stuff
A new report has found no strong evidence to link the Otago Regional Council's opening of a coastal mouth to fish deaths.

The report, released on Wednesday by the council, was independently written by Ryder Environmental.

The new report made a series of considerations for the council to undertake in future coastal mouth openings, which is done as a common flood mitigation measure.

The measures include monitoring of water temperature and coinciding openings with rainfall and tides.

Otago Regional Council's general manager for operations, Gavin Palmer, said the council would take the suggestions for minimising environmental risk on board.

It is always a concern when a significant fish kill occurs," he said.

Meanwhile, the council released another independent report, by Wynn Williams, on Wednesday, which reviewed the council's response to the fish deaths and whether the opening of the coastal mouth was compliant with relevant legislation.

Otago Regional Council chief executive Sarah Gardner said the report showed the coastal mouth opening was a permitted activity and that the council's investigation into the fish deaths was thorough, timely and sound.


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