Update on Dead Fish Found in Ottawa River


An investigation by Quebec’s Ministère de l'Environnement et de la Lutte contre les changements climatiques (MELCC) has revealed that certain conditions of operation at a hydroelectric power station in Quebec caused a phenomenon of supersaturation in dissolved gas in the Lièvre River, causing the death of many fish in July. Many of the dead fish flowed into the Ottawa River.
Supersaturation in dissolved gas is the condition that exists when the total dissolved gas pressure in water is greater than the atmospheric pressure at the surface of the water. Such conditions are a threat to aquatic life but do not pose a direct risk to human health.

The Eastern Ontario Health Unit, along with municipal partners and Ontario’s Ministry of Environment, Conservation and Parks (MECP), continues to monitor and assess the situation and will issue public statements if the need arises.