The Mediterranean Sea is being invaded by hundreds of fish, jellyfish, prawns and other marine species from outside the region.
More than 1 000 non-indigenous species have been identified in the Mediterranean and the Black Sea. Over half have established permanent populations and are spreading, causing concern about the threat they pose to marine ecosystems and local fishing communities.
“Climate change and human activities have had a profound impact on the Mediterranean and the Black Sea,” says Stefano Lelli, a fishery expert for the eastern Mediterranean working for the General Fisheries Commission for the Mediterranean (GFCM).
This regional fisheries management body, established by FAO, is leading efforts to promote sustainable fisheries and aquaculture in the Mediterranean and the Black Sea. It works with fishers, conservationists, scientists and government authorities to better understand the rise in non-indigenous species and help countries improve their mitigation and management measures.
“We have witnessed a swift and significant alteration of marine ecosystems, and this has led to several impacts on local communities' livelihoods. In the coming years, we expect the number of non-indigenous species to continue rising,” adds Lelli.
The Mediterranean Sea is undergoing a “tropicalization” process as water temperatures rise, largely due to climate change. In addition, many species have migrated via well-travelled shipping routes such as the Strait of Gibraltar or the Suez Canal, often attached to the hull of ships or inside them in the ballast waters. Other species, such as the Pacific cupped oyster and the Japanese carpet shell, were introduced for aquaculture during the 1960s and 1970s and have since escaped and colonized Mediterranean ecosystems.
Once established, non-indigenous species can outcompete native ones and alter their surrounding ecosystems, with potential economic implications for fisheries and tourism or even human health. For example, six poisonous and venomous non-indigenous fish species, such as pufferfish, lionfish and several jellyfish species, are now present in the eastern Mediterranean and can be toxic to humans if touched or ingested.
FAO’s GFCM is supporting Cyprus, Egypt, Greece, Lebanon, Israel, Syria and Türkiye in the complex task of mapping, monitoring and managing these invasive species. This Commission also serves as a forum for the affected countries to share information and strategies.
“The results and lessons learnt from this process should build knowledge on non-indigenous species so they can be managed effectively,” says Elisabetta Morello, GFCM Fishery Officer.