Half of the fish species may survive after the oceans warm up

Half of the fish species may survive after the oceans warm up

Warming ocean waters can destroy coral reefs. This will result in the extinction of not only the fish that live there, but also other species, experts say.

A new study led by a team at the University of Helsinki has shown how fish populations will respond to possible coral extinctions caused by warming.

The thing is that when the water warms up, more and more often it comes to the so-called coral bleaching that results from damage to symbiotic algae. This in turn leads to reef die-offs.

According to the current knowledge, some reef fish cannot feed themselves then, others have a chance to find other habitats among the rocks. However, it was not known yet which species would survive.

So the researchers from an international team first made a precise map of the world's reefs. This part of the project confirmed the already known coral diversity - for example, many species in particular live in the Indo-Pacific region. According to specialists, places with particular biodiversity are the result of a joint interaction of latitude, local habitat, temperature and geographical conditions.

It also found that more diverse reefs harbor more species of fish. “This is not particularly surprising given that corals are a unique food source for some species. They also provide a three-dimensional shelter that is enjoyed by numerous species. At the same time, fish that rely on corals can provide food for those who do not depend directly on corals, 'says Prof. Giovanni Home from the University of Helsinki.

The forecasts then made indicated that if the coral reefs died out, as much as 40% would be lost. species of fish. This is to result, among others from disturbance of food chains - species that do not directly use reefs will also suffer.

The extinction can vary in severity depending on the location. In the Central Pacific, for example, more than 60 percent of it would disappear. species of fish, and in the West Atlantic - 10 percent.

"For anyone who enjoys reef diving and the millions of people who feed on the fish that live there, this thought experiment should be a concern," says Kevin Lafferty of the University of California, Santa Barbara. - But it can also inspire more reef conservation measures. The benefits of this will extend far beyond the corals, extending to fish and other organisms that depend directly and indirectly on corals "- emphasizes the researcher.

More information on the pages:

https://www2.helsinki.fi/en/news/sustainability-news/a-future-ocean-that-is-too-warm-for-corals-might-have-half-as-many-fish-species">https://www2.helsinki.fi/en/news/sustainability-news/a-future-ocean-that-is-too-warm-for-corals-might-have-half-as-many-fish-species

https://royalsocietypublishing.org/doi/10.1098/rspb.2021.0274">https://royalsocietypublishing.org/doi/10.1098/rspb.2021.0274

Marek Matacz (PAP)

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