Anchovies, herring and pilchard could face extinction as warming oceans increase pressure on their survival and hamper their ability to adapt, new research suggests.
The study indicates that the fish will struggle to keep pace with accelerating climate change as warmer waters reduce their size, and therefore their ability to relocate to more suitable environments
Professor Chris Venditti, an evolutionary biologist at the University of Reading, and co-author of the study, 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 study, published in Nature Climate Change, comes as a report from the UN’s Intergovernmental Panel on Climate Change warned the world will reach or exceed temperature rises of 1.5C over the next two decades.
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 globally distributed fish species to study their evolution over 150 million years.
It focused on Clupeiformes – highly diverse fish found all over the world – including anchovies, Atlantic herring, Japanese pilchard, Pacific herring, and South American pilchard.
But the researchers say the findings have implications for all fish.
The findings support the expectation among scientists that fish will generally get smaller and move less as the world warms because they have to increase their metabolism and therefore need more oxygen to sustain their body functions.
Researchers suggest this will have an impact on fish species as larger fish are able to travel longer distances owing to their greater energy reserves. Smaller fish are less able to seek out new environments with favourable conditions as the climate changes.