An important part of the fish populations of seas and oceans are adapting to the increase in water temperature - a consequence of climate change - moving towards the poles in search of colder conditions and/or similar to the usual ones up to now for each of them. species, according to a data review study carried out by researchers from the University of Glasgow (United Kingdom), whose results have been published in the journal Global Change Biology.
Carolin Dahms and Shaun Killen, authors of this meta-analysis (a study in which they review the results of many other studies already published), recognize that up to now most of the research in this area has been carried out with species of fishing/commercial value, therefore that there is a bias that should be completed with research with many other species of marine animals.
In any case, the researchers from the University of Glasgow warn that not all marine species can migrate and adapt to the new climatic conditions, and that even some of those prepared to move may suffer serious losses due to the fact that in the new cold waters they will not find suitable habitats or food for their survival.
"By analyzing the breadth of current global data on changes in marine fish in recent years, the authors of the new study have discovered how fish populations in Earth's oceans are responding to rising sea temperatures." , explains the University of Glasgow in a general way in an informative note on the results of its two researchers.
The main takeaway is that, in response to warming oceans, many fish populations are moving toward Earth's poles or into deeper water, all in an attempt to stay cool.
"For marine life such as fish, the surrounding water temperature affects critical functions such as metabolism, growth, and reproduction," the authors recall. Additionally, marine species often have a very narrow habitable temperature range, making even small differences in the water impossible to manage. As a result, changes in marine life caused by global warming have been up to seven times faster than the responses of animals on land.
The authors of the new study have examined data on 115 species spanning all major ocean regions, with a total of 595 marine fish population responses to rising sea temperatures, the first time such a comprehensive global analysis has been conducted. .
Carolin Dahms, lead author of the study, said: "We observed a striking trend in which species that live in areas that are warming the fastest also show the fastest changes in their geographic distributions.
“The rate of warming in some regions may be too fast for fish to adapt, so relocation may be their best survival strategy. At the same time, we see that their ability to do so is also affected by other factors, such as fishing, as commercially exploited species move more slowly.
Professor Shaun Killen, lead author of the study, said: "While relocation to cooler waters may allow these species to persist in the short term, it remains to be seen how these changes will affect food webs and ecosystems.
"If the prey of these species don't move as well, or if these species become an invasive disturbance in their new location, there could be serious consequences down the road."
Furthermore, the study found that how we measure and report these climate responses is also important. While the current literature is biased towards commercially important northern species, further investigation of some of the most rapidly changing ecosystems, such as in the Global South, will be needed in the future to improve our understanding of how our oceans will change.