Photo taken on Aug. 5, 2018 shows the Rhone Glacier covered with white blankets near the Furka Pass in Switzerland. The Rhone Glacier is protected by special white blankets to prevent it from further melting as a result of global warming. (Xinhua/Xu Jinquan)

Fish and other marine life may have to flee thousands of kilometers to escape damaging heat waves, according to research published Wednesday, highlighting the scale of disruption caused by these increasing surges in ocean temperatures.

Hot spells can cause dramatic changes to ocean ecosystems, devastating coral habitats, killing large numbers of seabirds and forcing species like fish and whales into colder waters.  

Researchers said the increasing number of marine heat waves are a sudden shock to local ecosystems.

They are an additional stress on oceans that are also seeing long-term warming, says the journal Nature.

The researchers looked at how far a species caught in a marine heat wave would have to travel to get back to a normal water temperature, in what they term "thermal displacement." 

Previous research focused on measuring the intensity of the temperature change at the location of the heat wave and the effects on static habitats, like kelp forests and coral reefs, researchers said.  

Thermal displacement "adds a new dimension" to our understanding of these heat waves, lead author Michael Jacox of the US National Oceanic and Atmospheric Administration told AFP.

"It's important because we know that many marine species can quickly move long distances to find favorable habitats. They won't just stay in place when the water is too hot, so the question is how far must they go to find cooler water?" he said.

AFP