Investigation underway to determine cause of fish die-off in Port Franks, Ont.

Dead fish were found in the marina and beach of Port Franks, Ont. on July 28-29, 2023. (Source: Jennifer Powell)

An investigation involving the Ontario Ministry of the Environment, Conservation and Parks (MECP) and the Ausable Bayfield Conservation Authority (ABCA) is underway after a large number of dead fish were discovered in Port Franks.

In an interview with CTV News London, Jennifer Powell, an environmental researcher with the University of Toronto, said she heard reports of there being a fish kill on July 28.

A day later, dead fish were discovered found floating in the marina and along the beach.

On July 30, the Municipality of Lambton Shores said they were aware of the dead fish reports, and that the Ministry of Environment, Spills Action Centre and the Coast Guard had been contacted.

According to a release issued Tuesday, the MECP attended sites where dead fish were found to investigate possible causes of the fish die-offs, while a member of the ABCA also attended to assist in the investigation.

According to the conservation authority, the cause of a die-off of fish of a single species can be a virus. However, in this particular case multiple different species of fish have died.

“We appreciate the concern shown by our watershed residents and the reports they provided, to the ministry and to us, through phone calls and emails,” said Kari Jean, ABCA aquatic biologist.

Powell, who is researching endangered fish in the Ausable River this summer, said she’s heard reports of dead fish washing ashore all the way from Grand Bend to Ipperwash Beach.

While a virus, chemical spill or other combination of factors could be the culprit of the die-off, the ABCA said many contributing factors are at play, including low oxygen, temperature and weather.

Jean said it’s a “concern” when incidences like this occur, and that they are indicative of there being an underlying issue that needs to be addressed in order to reduce risks to freshwater fish.

“With the support of funding partners and local landowners, we are completing a number of local projects that can help to protect our fish species by slowing water down and allowing it to soak into the ground so that it doesn’t run off the landscape,” she said.

The investigation continues, and the ABCA said results will be made public once the MECP concludes its investigation.