Scientists at the University of Glasgow in Scotland say their research shows that the majority of fish populations in the world’s oceans are responding to climate change by relocating towards colder waters nearer the north and south poles.
This latest study, released on May 31, identifies many marine fish populations shifting toward the Earth’s poles or moving to deeper waters, all in an effort to stay cool. For much of marine life, water temperature affects critical functions such as metabolism, growth and reproduction. Various marine species have a very narrow livable temperature range. As a result, marine life changes caused by global warming have been up to seven-fold faster than animal responses on land.
This latest study examined data on 115 species spanning all major oceanic regions, totaling the responses of 595 marine fish populations to rising sea temperatures. It’s the first time such a comprehensive global analysis has been undertaken, according to the Glasgow scientists.
Over the last century, global warming has had substantial impacts on marine ecosystems, with fish species disappearing altogether from some areas. In some cases, marine fish may be able to adapt and change aspects of their biology in order to adjust to warmer conditions. Still, in many cases, a change in geographical range may be the only means of coping with rapid warming, the study showed.
As the current effects of global warming on marine ecosystems are predicted to increase, and with sea temperatures forecasted to keep rising, the ability of researchers to predict fish relocations will be vital to protect global ecosystems and maintain food security, researchers said.
The study’s lead author, Carolin Dahms, said it’s possible that the 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, she added, scientists have observed that their ability to do so is impacted by other factors such as fishing, with commercially exploited species moving more slowly.
The paper, titled “Temperature change effects on marine fish range shifts: a meta-analysis of ecological and methodological predictors,” is published in Global Change Biology.