The warming of marine waters compromises the future of many species of fish, which will become smaller and smaller and will find fewer places to live and develop properly. Although there have already been other events of climate change throughout the life of the Earth, the current one is so rapid that many fish do not have time to adapt to the new circumstances and seem doomed to extinction. This is what will happen with some species so widely consumed in Spain such as sardines, anchovies or herrings.
New research suggests that sardines, anchovies and herring will have Difficulty keeping up with climate change accelerated as warmer waters reduce in size and thus their ability to move to more suitable environments.
The study, published in Nature Climate Change, also provides the first evidence that refutes the theory that the changes that the planet undergoes will result in more species, since exactly the opposite will happen. This will be so because many species will be less able to evolve to cope with warmer temperatures, increasing its risk of extinction.
Professor Chris Venditti, an evolutionary biologist at the University of Reading and co-author of the study, said in a statement: “Warming waters is a double whammy for the fishAs it not only causes them to evolve to a smaller size, but also reduces their ability to move to more suitable environments.
‘Our research supports the theory that fish will get smaller as the oceans warm under climate change, but reveals the worrying news that they won’t be able to evolve either to deal with this situation as efficiently as originally thought. With sea temperatures rising faster than ever, fish will be left behind in evolutionary terms and will have to fight for survival, ”adds Venditti.
“This has serious implications for all fish and our food security, as many of the species we eat could become increasingly rare or even non-existent in the coming decades.”
The first solid evidence
The study, led by the Center for Advanced Studies in Arid Zones (CEAZA) in Chile and the University of Reading in the United Kingdom, used statistical analyzes of a large data set of globally distributed fish species to study their evolution during the last 150 million years.
The study provides the first solid evidence how historical fluctuations in global temperature have affected the evolution of these species.
Specifically, the research focused on the Clupeiformes, a very diverse group of fish found throughout the world and which includes species important to fisheries, such as anchovies, Atlantic herring, Japanese sardine, Pacific herring. and the South American sardines. However, the findings have implications for all fish, the authors say.
And is that marine fauna faces a situation never seen before. Until now, fish have only had to deal with a maximum average increase in ocean temperature of around 0.8 ° C per millennium. But that’s a much lower variation than current warming rates confirmed by the National Oceanic and Atmospheric Administration (NOAA), of 0.18 ° C per decade since 1981.
The findings support scientists’ suspicions that fish will generally get smaller and move less as the world warms up, because they will have to increase their metabolism and therefore require more oxygen to maintain their bodily functions.
This will affect small fish species, because larger fish can travel longer distances, due to their higher energy reserves, while smaller fish have a harder time finding new environments with favorable conditions as the climate changes.
The research contradicts the assumption that an increase in smaller fish will mean more new species emerge due to the concentration of genetic variations within local areas.
On the contrary, scientists claim that warmer waters would lead to the development of fewer new species, which would deprive fish of another key weapon in tackling climate change.
Previously, overfishing had been found to reduce fish size, so the new study only adds a new element of pressure to this set of marine species.
Reference study: https://www.nature.com/articles/s41558-021-01123-5
Statement from Professor Venditti: http://www.reading.ac.uk/news-and-events/releases/PR858656.aspx
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