Urgent action on climate change needed to rebuild fish stocks in Canada and beyond, study suggests

Spawning sockeye salmon, a species of Pacific salmon, are seen making their way up the Adams River in Roderick Haig-Brown Provincial Park near Chase, B.C., Tuesday, Oct. 14, 2014. THE CANADIAN PRESS/Jonathan Hayward

Fish stocks in Canada and globally will continue to decline and might never recover unless more action is taken to mitigate the impacts of climate change, a new study projects.

Dr. William Cheung, professor at the University of British Columbia's Institute for Oceans and Fisheries, is the study's lead author.

"Many of the fish stocks in the world are considered to be over-exploited and they need rebuilding and many regions and countries such as Canada aim to rebuild exploited fish stocks, such as Atlantic cod or Pacific salmon," he told CTV News.

"If we don't mitigate climate change, we will continue to see a decrease in these fish stocks."

He says researchers modelled a number of scenarios in order to gauge the effects of both a warming climate and fishing activity. A summary of the research explains that in a "worst case scenario" where nothing is done to mitigate global warming and overfishing continues, global fish stocks will further decline by 36 per cent.

"One of the reasons that we actually should care is that the fish are very important to the ecosystem as well as to people," Cheung said.

"Many people around the world, including many coastal communities in Canada are dependent on these fish stocks for their livelihood. Some of these communities, particularly Indigenous coastal communities, they really rely on this seafood as a main source of nutrients."

However, Cheung says the study does offer some insight into how to prevent further decline. Reducing fishing by an average of 25 per cent, for example, would allow stocks to rebuild even with a higher degree of warming. 

But he says managing fishing activity can't be the only strategy. Even if warming only increases by 1.5 C, which is the goal set in The Paris Agreement, the impact will likely be catastrophic in tropical regions.

"What the world is doing now in climate mitigation is not enough." Cheung says. "This study really highlights the importance of taking urgent action."

With files from CTV News Vancouver's Angela Jung