Invasive species and tropicalization in the Mediterranean

The Mediterranean Sea is undergoing a rapid ecological transformation driven by rising temperatures and the influx of non-indigenous species via the Suez Canal. Research indicates that a new non-native species enters the region approximately every two weeks. Documented non-native species have increased to over 1,000, up from fewer than 800 recorded by the European Environment Agency between 2012 and 2017. These organisms, including lionfish, blue crabs, and rabbitfish, are displacing native species, altering food chains, and threatening local fisheries.

In Cyprus, scientists are utilizing experimental traps to monitor and control aggressive species like the lionfish, which lacks natural predators in these waters. This is particularly critical given that while the Mediterranean accounts for only 0.8% of the global ocean area, it supports up to 18% of the world's marine species.

Prof. Dr. Deniz Ayas of Mersin University describes this phenomenon as the ‘tropicalization’ of the Mediterranean. As warming waters allow tropical species from the Red Sea—such as pufferfish, catfish, and various sea urchins—to establish stable populations, the entire biological structure, including plankton and seagrasses, is shifting.

Recent research from Tel Aviv University highlights this process, known as Lessepsian migration. The eastern Mediterranean is currently warming at approximately twice the global average rate, thinning the natural thermal barrier that previously prevented tropical species from surviving in northern waters. Scientists have identified three Red Sea fish—the star pufferfish, cinnabar goatfish, and yellowspotted trevally—that are highly predisposed for future migration.