More than 1,000 non-native species have been identified in the Mediterranean and Black Seas. More than half have established permanent populations and are spreading, raising concerns 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, an eastern Mediterranean fisheries expert who works for the General Fisheries Commission for the Mediterranean (GFCM).
This regional fisheries management body, established by the FAO, is leading efforts to promote sustainable fisheries and aquaculture in the Mediterranean and Black Seas. It works with fishermen, conservationists, scientists and government authorities to better understand the increase in non-native species and help countries improve their mitigation and management measures.
“We have witnessed a rapid and significant alteration of marine ecosystems, and this has caused various impacts on the livelihoods of local communities.
In the coming years, we hope that the number of non-native species will continue to increase”, adds Lelli.
The Mediterranean Sea is undergoing a process of “tropicalization” as water temperatures rise, largely due to climate change.
In addition, many species have migrated through busy shipping routes, such as the Strait of Gibraltar or the Suez Canal, often attached to the hull of ships or inside them in ballast water.
Other species, such as the Pacific cup 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-native species can outcompete native ones and disrupt surrounding ecosystems, with potential economic implications for fisheries and tourism or even human health.
For example, six species of poisonous and venomous non-indigenous fish, such as puffer fish, lion fish, and various species of jellyfish, are now present in the eastern Mediterranean and can be toxic to humans if touched or ingested.
This Commission also serves as a forum for affected countries to share information and strategies.
“The results and lessons learned from this process should generate knowledge about non-native species so that they can be managed effectively,” says Elisabetta Morello, GFCM fisheries officer.
Turning a threat into an opportunity Fishermen throughout the region have been affected by this trend.
However, with the support of the CGPM, they are finding new ways to turn these invasions into opportunities.
In southwestern Turkey, where invasive species can account for 80 percent of the catch in some areas, fishermen are gradually creating new consumer and export markets for species such as lionfish, sea urchins and Randall’s bream.
Lebanon is also training fishermen to catch non-indigenous species, encouraging consumers to try them.
“Rabbitfish, Red Sea goatfish and lionfish are some examples of non-native species that are becoming a source of income in Lebanon,” says Manal Nader, Associate Professor and Director of the Environment Institute of Lebanon.
Balamand University in Lebanon.
In Tunisia, two non-indigenous species of blue crabs, which threatened traditional fisheries, became a lucrative business when FAO and the Tunisian government helped connect fishermen to new markets.
The same is happening in Spain and other parts of the Mediterranean, which has triggered a specific GFCM research program to manage these species.
“Monitoring and mitigating the impacts of non-native species on marine ecosystems is costly and, in most cases, eradication is impossible,” says Miguel Bernal, GFCM Senior Fisheries Officer.
“Where commercialization and harvesting are possible, whether as a source of food, pharmaceuticals or otherwise, commercial fishing has proven to be the most effective tool to address this problem.”
Protection of native species To safeguard native species, the GFCM supports the creation of restricted fishing zones.
Well-preserved areas have been shown to be more resistant to the impact of non-native species.
“International and regional cooperation, as well as concerted action, is needed to address non-native species in the Mediterranean and Black Sea,” says Bayram Öztürk, author of the GFCM study on non-native species in the Mediterranean.
“It goes without saying that the impacts of non-native species must be monitored by all countries in the region.
Once a species is introduced, it may be too late to eradicate it.”
With the GFCM study, Non-native Species in the Mediterranean and Black Sea, as a first step, the Commission is now working with countries in the region to adapt fishing techniques, connect with new markets and help fishermen to create new livelihoods from these catches, while also maintaining their crucial work of preserving marine ecosystems through protected areas.