UBC Urges Strong Action to Mitigate Climate Change

Image: The University of British Columbia.

A new study released by the University of British Columbia is projecting the impact of different global temperature increases and ranges of fishing activity will have on biomass, or the amount of fish by weight in a given area, from 1950 to 2100.

The simulations suggest that climate change has reduced fish stocks in 103 of 226 marine regions studied, including Canada, from their historical levels, and that these stocks will struggle to rebuild their numbers under projected global warming levels in the 21st century.

According to lead study author William Cheung, a professor at Canada’s Institute for the Oceans and Fisheries, more conservation-oriented fisheries management is essential to rebuild over-exploited fish stocks under climate change. But that alone is not enough, Cheung added.

The study projected that on average, when fisheries management focuses on the highest sustainable catch annually, that the additional climate impact on fish at 1.8 degrees Celsius warming would see fish stocks unable to rebuild themselves. If people worldwide fished only three quarters of the annual highest sustainable catch, fish stocks would be unable to rebuild at a higher degree of warming 4.5 degrees, according to the report.

Cheung noted that tropical eco-regions in Asia, the Pacific, South America and Africa are seeing a decline in fish populations as species both move further north to cooler waters and are also unable to recover due to fishing demands.

The study shows that even a slight increase of 1.5 degrees Celsius could have a catastrophic impact on tropical nations dependent on fisheries for food and nutrition security, revenue and employment, Cheung said.

The study shows that due to climate change the world is unlikely to return to historical levels of fish stocks. The world is at a turning point and what is needed is a coordinated global effort to develop practical and equitable marine conservation measures to support effective biomass rebuilding under climate change, he explained.

“These need to recognize the ways that marine biodiversity contributes to livelihood and economies, particularly in tropical marine ecoregions, as well as requiring more stringent limits on fishing activities to achieve greater biomass rebuilding potential,” he remarked.