As oceans warm, coral reef fish might prefer to move rather than adapt

Date: October 5, 2016

Source: University of Texas at Austin

Scientists have new evidence that coral-reef fish -- who are capable of adapting to warmer temperatures brought about by global climate change -- will probably opt instead to relocate to cooler parts of the ocean.

In experiments using a fish found in coral reefs around the world, the blue-green damselfish, Chromis viridis, researchers found that the fish were capable of adapting to living in water 2-4 degrees Celsius above their normal summer temperatures; however, when given the slightest chance, the fish moved to cooler water.

"When fish have to adapt to increased temperature, there are physical consequences. They may not be able to handles stress, or reproduce, or even grow," said marine scientist Dr. Jacob Johansen from The University of Texas at Austin. "But, when they seek out temperatures that they've evolved to be in over thousands of years, they can mitigate the impact of increasing temperatures and not sacrifice critical physiological processes."

Johansen and fisheries biologists from the University of Copenhagen and James Cook University collaborated on the study, published in the journal Global Change Biology.

Marine fish are faced with a tough decision. The ocean is warming at a faster rate than occurs on land, because oceans operate as sinks -- trapping in the heat. Many ocean fish will need to adapt or move to avoid death.

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