There are 200 new fish in the Mediterranean and it is the most invaded sea in the world. This is revealed by a research published by the journal ‘Global Change Biology’ – and coordinated by the Institute for biological resources and marine biotechnologies (Cnr-Irbim) of the Cnr of Ancona – which reconstructs the history of biological invasions in the mare nostrum. The study shows that in the last 130 years the Mediterranean has undergone the arrival of about two hundred new fish species thanks to climate change and, with hundreds of exotic species, it is now recognized as the most invaded marine region in the world. The research reconstructs this history for fish species introduced since 1896 and was carried out thanks to the support of the InterregMed Mpa-Engage projects and the @Cnr Useit project. The research coordinator Ernesto Azzurro of Cnr-Irbim explains that “the study demonstrates how the phenomenon has had an important acceleration since the 1990s and how the most recent invasions are capable of the most rapid and spectacular geographical expansions” . “For over a century – continues Azzurro – researchers from all Mediterranean countries have documented this phenomenon in the scientific literature, identifying over 200 new fish species and reporting their catches and their progressive expansion” and “thanks to the review of hundreds of these articles, and the georeferencing of thousands of observations, we were able to reconstruct the progressive invasion in the Mediterranean “. Experts note that this process has forever changed the history of our sea and point to two gateways to this colonization. “The species of the Red Sea, which entered the Suez Canal inaugurated in 1869, are the most represented and problematic. There are, however, other important vectors such as naval transport and release from aquariums. The researchers also considered the Atlantic origin via the Strait of Gibraltar “says Azzurro again. But what are the environmental and socio-economic effects of these ‘fish migrations’? “Some of these species constitute new resources for fishing, well adapted to tropical climates and already used in the easternmost sectors of the Mediterranean” explains the researcher Cnr-Irbim. At the same time, Azzurro stresses that “many ‘invaders’ cause the deterioration of natural habitats, drastically reducing local biodiversity and competing with native, endemic and more vulnerable species”. “The pace of colonization is so rapid that it has already changed the faunal identity of our sea. Therefore, reconstructing the history of the phenomenon allows us to better understand the transformation taking place and provides an emblematic example of biotic globalization in the marine environments of the entire planet” finally affirms the researcher of the Cnr.