Climate Change Could Devastate Tropical Fisheries

A new study finds that as the oceans warm, fish will become smaller and head toward cooler waters.
(Photo: Flickr)
Dec 4, 2015· 1 MIN READ
Taylor Hill is an associate editor at TakePart covering environment and wildlife.

This year is likely to be the first time the earth’s average annual temperature will be 1-degree Celsius warmer than it was prior to the industrial age.

But if global greenhouse gas emissions continue at their current pace, the world’s oceans are expected to see an average surface-temperature increase of 2 degrees to 3.5 degrees by the end of the century, which could dramatically affect the survival of scores of marine species.

“The types of fish that we will have on our dinner table will be very different decades later compared to now,” William Cheung, associate professor at the University of British Columbia, said in a statement.

The fish on people's dinner plates will change due to climate change and ocean acidification, according to University of British Columbia scientists.

Cheung is codirector of the Nereus program—a global initiative founded by the Nippon Foundation and the university to promote sustainability of the world’s oceans.

In a report released for the Paris climate talks, Nereus outlines how climate change, overfishing, and habitat destruction could devastate the world’s seafood supply.

The maximum weight of fish communities is expected to shrink, on average, by 14 to 24 percent globally from 2000 to 2050 under a high CO2 emission scenario. (Chart: Nereus)

As the oceans heat up, the tropics—where many island nations depend on fisheries for survival—will be the first to notice a change. Fish are expected to move to cooler water, generally toward the poles, in the coming years.

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Unless the world curbs carbon emissions, mass fish migration from the tropics is expected to occur 65 percent faster than if global temperature increases are limited to 2 degrees.

Additionally, a warming ocean means smaller fish—hotter temperatures can stunt growth and reproduction in many fish species.

Under a “business as usual” emissions scenario, the weight of fish on average is expected to shrink by 14 to 24 percent globally from 2000 to 2050.

“Fisheries will be catching more warm-water species, of a smaller size, and that will affect fish supply through our domestic and oversea fisheries as well as imports,” Cheung said.

“Global marine ecosystems have already been largely altered by overfishing,” Daniel Pauly, a University of British Columbia professor and an adviser to the Nereus program, said in a statement. “This report clearly points out that any solution needs to deal with the CO2 problem as well.”