Fish deaths caused by over-gasified water

OTTAWA — Quebec’s environ-ment ministry says an oversat-uration of gas in the water at a dam at Brookfield Hydroelectric Centre is to blame for causing waves of fish to die this sum-mer.

Michel Rousseau, an assistant deputy minister for environ-mental control and dam safety, said Thursday that research by that ministry in recent weeks has shown that water flowing out from the dam into the Lievre River is too full of tiny air bubbles.

He said that when the fish swim in this bubbly water and filter it through their gills, it can cause them to die from a “gaseous embolism.” Speaking to reporters on Thursday, Rousseau said Quebec’s environment ministry has ordered the plant’s operators at renewable energy corporation Evolugen to carry out an inquiry to determine the specifics of how the dam is causing the water to become too gaseous, and how to solve the problem.

In the short term, the ministry is also ordering the dam’s managers to take measures to reduce as quickly as possible the amount of gas being put into the water at the dam.

Quebec’s environment minis-ter Benoit Charette said that it’s imperative that activities at the dam “be carried out with respect for the environment, and in this case, for the aquatic wildlife.”

“I am using measures at my disposal to do the maximum to ensure a return to normalcy in Gatineau,” he added in the provided statement in French.

The cause of the fish kill, which showed up en masse on Ottawa and Lievre river banks on July 8, 19, 29 and 31, had until now been a mystery, though Charette had said in previous comments that his ministry believed the Brookfield dam in Masson to be the cause.

On Thursday, Rousseau explained that other conditions in the water, such as temperature or content of bacteria or toxins, are not at levels that would normally cause fish deaths on this scale, and can thus be ruled out as causes.