Commonly eaten fish could face extinction as planet warms

Most commonly eaten fish could face extinction as the oceans warm, according to researchers at the University of Reading. 

In the study, published in Nature Climate Change, the researchers used statistical analyses of a large dataset of globally distributed fish species to study their evolution over the past 150 million years. 

Their findings support the long-held expectation that fish will generally get smaller and move less as the world warms, due to having to increase their metabolism and needing more oxygen to sustain their body functions. 

This will impact smaller fish species because larger fish are able to travel longer distances owing to their greater energy reserves, whereas smaller fish are less able to seek out new environments with favourable conditions as the climate changes.

This means that fish species such as sardines, pilchards and herring will struggle to keep pace with accelerating climate change.

Overfishing has also been found to make fish smaller in size, so the new study adds to the list of pressures they face as a consequence of human actions.

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.

‘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.’

Photo by Linda Robert