17th May 2013

"Fish thermometer" reveals long-standing, global impact of climate change

Fish have been migrating toward Earth's poles in search of cooler waters since at least 1970, according to a new study by the University of British Columbia (UBC) that reveals yet more evidence of a warming planet. This has major implications for global food security in the future.

In a Nature study published this week, UBC researchers used temperature preferences of fish and other marine species as a sort of “thermometer” to assess effects of climate change on the world's oceans between 1970 and 2006.

They found that global fisheries catches were increasingly dominated by warm-water species, as a result of fish migrating towards the poles in response to rising ocean temperatures.

“One way for marine animals to respond to ocean warming is by moving to cooler regions,” says the study’s lead author William Cheung, an assistant professor at UBC’s Fisheries Centre. “As a result, places like New England on the northeast coast of the U.S. saw new species typically found in warmer waters, closer to the tropics.

“Meanwhile in the tropics, climate change meant fewer marine species and reduced catches, with serious implications for food security.”

“We’ve been talking about climate change as if it’s something that’s going to happen in the distant future – our study shows that it has been affecting our fisheries and oceans for decades,” says co-author Daniel Pauly, principal investigator with UBC’s Sea Around Us Project. “These global changes have implications for everyone in every part of the planet.”

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