Climate change driving away marine fish towards poles: Study

Global warming is causing the majority of fish populations in the sea to relocate towards colder waters nearer the north and south poles, according to a study on the impact of climate change on oceans.

The researchers from the University of Glasgow in the UK found that, in response to ocean warming, many marine fish populations are shifting towards the Earth's poles or are moving to deeper waters—all in a bid to stay cool.

For marine life such as fish, the temperature of the surrounding water affects critical functions such as metabolism, growth and reproduction.

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Marine species also often have a very narrow livable temperature range making even small differences in the water impossible to cope with. As a result, marine life changes caused by global warming have been up to seven-fold faster than animal responses on land, the researchers said.

The study, published in the journal Global Change Biology, examined data on 115 species spanning all major oceanic regions, totalling 595 marine fish population responses to rising sea temperatures.

"We observed a striking trend (where) species living in areas that are warming faster are also showing the most rapid shifts in their geographical distributions," said Carolin Dahms, lead author of the study.

"It's possible that rate of warming in some regions may be too fast for fish to adapt, and so relocating may be their best coping strategy. At the same time we see that their ability to do so is also impacted by other factors such as fishing, with commercially exploited species moving more slowly," Dahms said.

While relocation to cooler water may allow these species to persist in the short-term, it remains to be seen how food-webs and ecosystems will be affected by these changes, the researchers added.