A hydro plant along the Lièvre River is being investigated in the deaths of more than 2,000 fish that have washed up on riverbanks in Ottawa and eastern Gatineau, Que., over the last month, according to Quebec Environment Minister Benoit Charette.

Several species of fish have been spotted floating on the surface of the Ottawa and Lièvre rivers and beached along shorelines since July 10, sparking concerns from the Ottawa Riverkeeper and local residents about the safety of the water.

Necropsies on the first fish determined they likely died from a toxic spill.

But in a French-language interview with RDI, Radio-Canada's news network, the minister said there was no such spill.

"What is reassuring for the public is that we are not talking about a chemical spill or a product causing these deaths," Charette said.

"Rather we are talking about the nature of the operations of the plant in question."

Nothing has changed, plant spokesperson says

The plant is operated by Evolugen, the new name for Brookfield Renewable Canada, and is stationed along the Lièvre River in east Gatineau's Masson-Angers community.

The minister has called for an investigation to determine if the plant is responsible for the masses of dead fish, and said a command post will be set up near the plant.

A probe is also being placed in the river to analyze the water continuously, according to the Environment Ministry.

Results from tests on dead fish are expected to be received by the ministry on or about Aug. 6.

Lorian Belanger/CBC More

Meanwhile, a spokesperson for Evolugen said in a written statement Thursday that the company learned of Charette's comments from the media.

The statement also said nothing has changed about the company's operations or the way it produces electricity.

"It must be remembered that we do not add anything to the water of the river to produce electricity. We continue to offer our full co-operation to the various government entities responsible," the statement reads.

Gatineau mayor awaiting answers

The minister called Gatineau Mayor Maxime Pedneaud-Jobin to update him on the government's investigation.

The company has been a good corporate citizen in the past, the mayor said, and he is convinced it will co-operate with the investigation so the government can get to the bottom of what is happening in the river.

In the meantime, he said the minister assured him the government is also looking into other potential causes.

"We will be totally reassured once we understand what happened, because it's clear that nature is sending us a message and we have to listen," Pedneaud-Jobin said.

"Something is happening."

The minister was not available for further comment Thursday afternoon.

In a French statement earlier this week, Environment Canada said it's working with the province and other groups to determine the cause and whether any laws have been broken.