Climate change

Mediterranean marine life fleeing to deeper waters, study finds

Written by Oceanographic Staff

As the oceans warm, marine life needs to find different coping mechanisms. In the Mediterranean, sea creatures flee to deeper, cooler waters, according to a new study.

A study, conducted by a team of researchers at Tel Aviv University and published in the journal Global Ecology and Biogeography, provides some insights into the reaction of Mediterranean marine life to climate change.

It argues that climate change and rising ocean temperatures make numerous marine species in the Mediterranean Sea change their habitats as they migrate dozens of metres deeper into cooler waters to survive. The team of researchers behind the study warns that ‘we are reaching the limit of many species’ capacity’.

By analysing 236 marine species collected in previous bottom-trawl surveys and their depth distribution, the team found that many fish, crustaceans and mollusks migrate approximately 55 metres deeper across the Mediterranean than they did in the 1980s. However, this pattern was not uniform between all species. While cold-water species migrate deeper than warm-water species, the study also found that “deep-water species deepen more than shallow-water species”.

While the entire planet experiences warming temperatures due to climate change, the research team says that it has been even more noticeable in the Mediterranean Sea. According to the study, the average water temperature in the Mediterranean rises by one degree Celsius every 30 years, while the rate is accelerating in the region.

Professor Jonathan Belmaker, who supervised the study, said: “It should be remembered that the Mediterranean was hot in the first place, and now we are reaching the limit of many species’ capacity.”

PhD student Shahar Chaikin added: “Our research clearly shows that species do respond to climate change by changing their depth distribution, and when we think about the future, decision-makers will have to prepare in advance for the deepening of species. For example, future marine nature reserves will need to be defined so that they can also provide shelter to species that have migrated to greater depths. And on the other hand, fishing in the future will involve fishing the same fish at greater depths, which means sailing further into the sea and burning more fuel.”

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Photography courtesy of Unsplash.

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