'Canary in the Ocean': Massive Fish Flight Shows Climate Change is Here

As ocean waters continue to heat up along with the rest of the planet, fish and other aquatic life forms are fleeing from their habitual regions to find the lower temperatures they have depended on for centuries, according to a new study released Wednesday.

"Fish are kind of the canary in the coal mine here, or the canary in the ocean," Boris Worm, a professor of marine biology at Dalhousie University in Halifax, Nova Scotia, who was not part of the study, told the Washington Post. "They are showing you [climate change] is underway. It's changing, and they are adapting. And the question is, how will we adapt? Or will we?"

The report, published in the journal Nature and conducted by researchers at University of British Columbia, shows that as the planet consistently warmed over the past few decades, fish have been pushed further and further towards the world's poles--upsetting ecosystems around the globe.

"This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions," the report states.

The study is the first of it kind, showing worldwide fish migration from as far back as 1970.

The Washington Post reports:

William Cheung, Daniel Pauly and their colleagues at the University of British Columbia looked at 52 distinct marine ecosystems that cover most of the world's coastal and shelf areas. Even after accounting for the impact of fishing and wide variations in the oceans that cover 71 percent of the planet, water temperatures rose steadily each decade between 1970 and 2006.

The researchers used the fish themselves as a kind of thermometer to demonstrate the increase in water temperature. By looking at the size of the catch in species' new habitats and comparing it with their preferred locations in 1970, the researchers calculated the "mean temperature of the catch," which, they said, rose significantly each decade over that 36-year period.

The authors said the migration of sea life poses the greatest danger to people in the tropics. As sea life moves away from the equator and toward both poles, new species are not moving in to replace them in the planet's warmest waters, the authors found. [...]

Merrick said warming seas affect not only sea creatures but also the food web on which they depend. Warmer temperatures may have affected the zooplankton population upon which some species feed, forcing them to look elsewhere for food, he said.

The research is one more confirmation that "global change is real and has been real for a long time," Worm added. "It's not something in the distant future. It is well underway."

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