The Prince Albert II Foundation has endeavoured to support, over five years, a new CIESM Program – CIESM Tropical Signals Program – that will detect, quantify and map changes of selected, sensitive species indicating climate warming in the Mediterranean Sea.

In the Mediterranean Sea, changes in biodiversity are occurring at unprecedented rate. In particular, the warming of Mediterranean waters¹, is accelerating the establishment of tropical species² and the retreat of temperate species towards colder areas of the Basin. There is evidence that “tropicalization” has triggered the population growth of certain marine species that in the past occurred only rarely, facilitating the migration of thermophilic organisms in new habitats. For example, the barracuda fish (Sphyraena viridensis), a close relative of the tropical barracuda (Sphyraena barracuda) and a fierce predator of cephalopods, crustaceans and fishes, is becoming extremely common in Mediterranean waters. Such species, often of low economic value, may outcompete local species of commercial importance, for instance leading to marked impacts on fishery economy. The undesirable mass events of jellyfish, observed more and more frequently across the Mediterranean Sea, could be also related to climate change.

Despite the increasing signals of change, this ongoing process of Mediterranean “tropicalization”, remains poorly understood, based on fragmented, occasional, usually local observations.

Support from the Prince Albert II Foundation will help CIESM in establishing a cross-basin “warning system” network of sensitive, indicator species for early detection of marine biodiversity changes in response to climate.