Dead fish at Cobourg Marina are not cause for alarm

Alewife Fish dead in Cobourg Marina. By Dan Jones, Northumberland 89.7 FM News, LJI

By: Cecilia Nasmith, Northumberland 89.7 FM News

Cobourg

Following reports of a fish die-off event affecting the Cobourg Marina, staff investigations have identified the fish as the Alewife Fish.

This is a member of the herring family, abundant in Lakes Ontario and Erie. May and June are their months to move to shallow waters to spawn – an activity that is stressful and requires a lot of energy.

“Springtime mortality due to sudden changes in water temperature are common for Alewife Fish in the Great Lakes, which is what has occurred along the shoreline of Cobourg, causing a surplus of deceased fish to wash into the Cobourg Marina and Harbour,” Environmental Services Department Environmental Technician Jennifer Leno said in the town's press release.

The Town of Cobourg would like to inform citizens that this is not an unusual occurrence at this time of year. It can fluctuate, depending on the severity of the weather, but it occurs continuously in varying degrees – the last such large die-off event occurred in 2019.

The Ministry of Natural Resources and Ontario Fish and Wildlife have confirmed similar situations elsewhere along Lake Ontario shorelines. A ministry statement said, “While the sight of dead fish can be concerning, it is important to note that these events are natural and not indicative of a larger environmental or health crisis.”

The Ministry advises avoiding contact with any dead fish, and reporting these instances to MNR at 1-800-387-7332.

For questions, please contact the town's Environmental Services Department at 905-372-7332.