There’s been a lot of anecdotal evidence that fish are migrating as a result of global warming. Over the past few decades, folks in the fishing industry have been noticing shifts in the quantity and type of their catch.
Now a major scientific study published in the journal Nature reports that since the 1970s, the composition of world’s major fisheries has changed. And that warming waters are the culprit.
After establishing temperature preferences for 990 fish and other marine animals, the research team looked at the tonnage of each species caught in 52 marine ecosystems that make up most of the world’s fisheries. Then, for each ecosystem, they looked at the temperature preference of each species, weighted by the amount caught from 1970 to 2006.
With the exception of the tropics, most of the areas scrutinized saw an increase in warm-water marine life and declines in cold-water species. And the increase in warm-water species was strongly correlated with increasing ocean temperatures.
The study’s lead author, William Cheung, is a professor at the University of British Columbia’s Fisheries Centre.
“We know that when the ocean warms, the organisms will try to find areas where they can grow best. One of the ways that they respond to the warming of the ocean is to shift their distributions to colder areas such as high latitude or in deeper waters. So we will expect to see that will affect fisheries catch because the fisheries are actually catching what is available in the ocean or in the fishing grounds.
This study is one more piece of evidence that climate change is happening now, with real consequences.
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Web Links
Warming Oceans are Reshaping Fisheries
Signature of Global Warming in Ocean Fisheries Catch
http://www.nature.com/nature/journal/v497/n7449/full/nature12156.html
Photo, taken on July 1, 2008, courtesy of Anderson Smith via Flickr.
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