STORIES
Blue Crab Crisis: Threat or Opportunity?
The blue crab invasion threatens fisheries in Italy, but Tunisia’s response offers a potential model for turning this crisis into an economic opportunity.
Tunisia

It can be described as a species substitution. It has arrived in the Mediterranean Sea from other parts of the World and found the right conditions to proliferate. But the consequences for fisheries are disastrous, with millions of euros of losses in terms of drastic drops in catches of fish, shellfish, and clams, the ruin of fishing gear, and hours of lay-offs. It's the case of the blue crab that exploded on the Italian coasts, especially in the northern Adriatic, in the summer of 2023. Italy is one of many countries that are dealing with this problem, and in the meantime, from the south coast of the Mediterranean Sea, Tunisia has something to teach.
When blue crabs skyrocketed in the North African Country in 2017, many fishermen lost their jobs and sold their boats. In response, 'the government deployed a contrast and adaptation strategy,' as explained by Stefano Liberti, journalist and writer, author of the book Tropico Mediterraneo—Viaggio in un mare che cambia (published by Laterza).
Tunisia promoted the creation of processing plants, gave subsidies to Tunisian and foreign investors, provided tax relief and a subsidy for purchasing raw materials, and paid a portion of the raw materials to the fishermen. So, many fishermen re-started to work. 'Today, there are 51 blue crab processing plants in Tunisia, producing it in all forms—whole, cut, cooked, raw, caviar, pulp', and 30 million euros of exports in 2022.'
'Today, there are 51 blue crab processing plants in Tunisia and 30 million euros of exports in 2022.'
For Liberti and Massimo Zuccaro, head of the Blue Economy and Sustainable Coastal Area Development of the International Centre for Advanced Mediterranean Agronomic Studies (Ciheam), the Tunisian one is a possible way forward. According to Liberti, Italy could replicate this model, but there are two main problems. The first is the certainty of investment. "We are talking about a huge amount of resources in a sector that does not exist yet', explains. "The second is that the Tunisian factories already occupy the market. So we should maybe find another market niche, playing on Made in Italy," he says.
And yet, 'the current numbers of the resource are so high to justify a similar effort,' and even Italian fishermen are looking in that direction, trying to ask the government to guarantee the purchase of blue crab at 1.5 euro per kilo allowing them to work and ensuring a minimum price.
Then, in the medium and long term, 'the construction of fair supply chains around the blue crab is paramount,' Zuccaro points out. One of the major problems now is the meager profit for fishermen. 'The price paid to the blue crab fisherman ranges from 0.5/1 euro to a maximum of 2 euro per kilo, depending on the size, while the fresh product is retailed at around 13-15 euro for the largest males (800-900 grams), 8-9 euro for the medium-sized ones (300-400 grams), 4-5 euro for the smallest (150-300 grams)', he says.
'For sure, we need to work on structuring a supply chain that makes fishing more profitable by experimenting with selective fishing gear that directs the capture of larger specimens and trying, more generally, to create value around the 'blue crab' product," Zuccaro explains.
So, the sale of fresh blue crab is 'only one possibility,' and 'there are other sales and production systems that would allow a tenfold increase in value,' he says. For example, the meat yield of blue crab is around 25 percent, but if it is sold when the carapace is not hard, the yield is close to 100 percent.
Another element is 'the possibility to enhance the waste from blue crab production' and see if, in addition to sending it to landfill, 'it's possible to activate innovative supply chains with a view to the circular economy, allowing further profit opportunities to around the blue crab potential industry.''
These are some of the challenges that CIHEAM intends to launch for research and development cooperation and collaboration in the Adriatic and the Mediterranean, with those Countries experiencing the same difficulties and problems related to the blue crab invasion. Zuccaro describes how 'this kind of work could be done within the next 3-5 years.'
The starting point is how to make the chains sustainable. And here, for Zuccaro, a paradigm shift is needed to understand that it 'is difficult to eradicate alien species when they become established.' So a new management perspective comes into play: as if the species is considered 'a native fish resource.''A new management perspective comes into play: as if the species is considered 'a native fish resource.'
This step has already been taken with the clam since it is an alien species imported in Italy from the Philippines by the Goro biologist Francesco Paesanti. 'There was a real biological explosion on the Po Delta River, which resulted in a significant profit. But at the same time, it created a fragile system based on one single mollusk presence,' Liberti remembers.
Today, a new alien species arrives in the same areas, supplanting the imported one. It is triggering issues for local and national economies. But 'in these crises, opportunities must be seized' and 'research and institutions have to be timely in coming up with solutions: stalling leads to being at the mercy of the waves,' Zuccaro concludes. For Liberti, the blue crab and hundreds of other alien species that arrived in the Mediterranean Sea 'are not the cause but a symptom of a wider crisis' in the environmental balance and management. 'We should take these phenomena as signals that the sea is sending us and pay more attention to what is happening.' Finally, learn the lesson.