Consumers could soon find it increasingly difficult to get their hands on their favourite fish. According to a new study, warming oceans are increasing the pressure on their survival and could hamper their ability to adapt. Research published in Nature Climate Change suggests that warmer waters reduces their size and therefore their ability to relocate to more suitable environments.
Researchers say the study is the first to counter the scientific theory that decreased movement will result in more species, by suggesting the opposite is true.
Professor Chris Venditti, an evolutionary biologist at the University of Reading, said: “Warming waters are a double whammy for fish, as they not only cause them to evolve to a smaller size, but also reduce their ability to move to more suitable environments.”
He added: “Our research supports the theory that fish will get smaller as oceans warm under climate change, but reveals the worrying news that they will also not be able to evolve to cope as efficiently as first thought.
“With sea temperatures rising faster than ever, fish will very quickly get left behind in evolutionary terms and struggle to survive.
“This has serious implications for all fish and our food security, as many of the species we eat could become increasingly scarce or even non-existent in decades to come.”
The new research, led by the Centre for Advanced Studies in Arid Zones (CEAZA) in Chile and the University of Reading, used statistical analyses of a large dataset of globally distributed fish species to study their evolution over 150 million years.
The scientists claim that it provides the first solid evidence of how historical global temperature fluctuations have affected the evolution of these species.
It focused on Clupeiformes – highly diverse fish found all over the world.
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The findings support the expectation among scientists that fish will generally get smaller and move less as the world warms.
This is due to having to increase their metabolism and therefore needing more oxygen to sustain their body functions.
The warning comes after a damning report from the UN’s Intergovernmental Panel on Climate Change warned the world will reach or exceed temperature rises of 1.5C in the next two decades.