Marine heat waves could wipe out fish stocks, UBC study finds

Howe Sound, B.C., is seen here in an undated file photo.

Vancouver -

A new study from the University of British Columbia says extreme temperatures caused by climate change will eliminate hundreds of thousands of tonnes from the world's fishery catch in addition to decreasing fish stocks.

In the worst-case scenario, where no action is taken to mitigate greenhouse gas emissions, researchers say they expect a six per cent drop in the amount of potential catches per year and a 77 per cent decrease in exploited species.

The study also suggests the effects from heat waves on fish stock would result in fisheries' revenues being cut by about three per cent and employment being chopped by two per cent globally, resulting in a potential loss of millions of jobs.

William Cheung, the lead author and director of UBC's Institute for the Oceans and Fisheries, says the study highlights the immediate need for Canada to develop ways to deal with extreme temperatures.

He says better data and active fisheries management systems that account for changes in ocean conditions will be vital.

Cheung says potential adaptations include adjusting catch quotas in years when fish stocks are suffering from extreme temperature events or, in extreme cases, temporarily closing fisheries so stocks can replenish.

“We need to have the mechanisms in place to deal with this,” Cheung said. “We also need to think ahead about how to help coastal communities by reducing any potential hardships these interventions may place.”

The heat wave that hit Western Canada in June, which set an all-time Canadian temperature record and resulted in the estimated death of more than a billion marine animals along the Pacific coast, shows these extreme heat events are already happening and having negative effects on marine life, Cheung says.

“We now know these extreme temperature events will happen, so we need to reduce the long-term stress on our systems, in regard to both fish stocks and fisheries, and do a better job at reducing greenhouse gas emissions,” he said. “The current action is not efficient and we need to do more to achieve that.”

This report by The Canadian Press was first published Oct. 2, 2021.