In the second half of August 2026, a scientific experiment is under way along the Italian Adriatic coast that could prove groundbreaking for the ecology of the Mediterranean. Some 500,000 small octopuses are being released off the shores of Riccione and Cesenatico, with the aim of curbing biologically the blue crab invasion that has been spreading for years. The Octo-Blu project, coordinated by the Emilia-Romagna region and the University of Bologna, is one of the largest experiments of its kind ever conducted in the Mediterranean and is attracting international attention. On the morning of 24 August, a further release of juvenile octopuses took place off Cesenatico, as the Italian regional portal Forlì Notizie documents in its latest coverage, in the presence of the regional Minister for Agriculture and Fisheries, Alessio Mammi.
What the Octo-Blu project entails
The project bears the name Octo-Blu and was launched in 2024 by the Emilia-Romagna region in partnership with the Dipartimento di Scienze Mediche Veterinarie of the University of Bologna, within the framework of the European programme FEAMPA 2021-2027 (Fondo Europeo per gli Affari Marittimi, la Pesca e l'Acquacoltura). As the official news page of the Emilia-Romagna region documents in its announcement of 24 August, the releases, which have been carried out since 19 August using fast vessels of the Capitaneria di Porto of Cesenatico, are conducted under the scientific leadership of Professor Oliviero Mordenti and the researcher Antonio Casalini. As the university magazine of the Alma Mater Bologna reports in addition, the juvenile octopuses come from the university's breeding facilities and some are only a few days old. In the second half of August, a total of around 500,000 young octopuses of the species Octopus vulgaris are being released.
The choice of the two test areas is ecologically grounded. Off Riccione, in the province of Rimini, submerged barriers exist that have been colonised by marine organisms over the years and are rich in caves and hiding places, the natural habitat of the octopus. Off Cesenatico, in the province of Forlì-Cesena, artificial octopus dens have been created on the sandy seabed within an area closed to fishing, since the upper Adriatic features predominantly flat and sandy substrates in which the octopus cannot survive without places of shelter.
The blue crab and its ecological consequences
The blue crab (Callinectes sapidus), also known as the blue swimmer crab , originates from the Atlantic coast of North America and is thought to have reached the Mediterranean via the ballast water of merchant vessels. As the specialist portal Italia a Tavola notes in its detailed analysis of the project, the species has multiplied explosively in the Adriatic in recent years, favoured by rising water temperatures and altered salinity levels in the coastal waters of the Po Plain. The blue crab feeds almost indiscriminately: mussels, clams, smaller fish and crab larvae, causing considerable damage to the fishing and aquaculture enterprises that underpin the coastal economy of Emilia-Romagna, Veneto and the Marche.
The economic dimension has now grown so large that entire families of clam farmers around Chioggia and Goro have been forced to close their operations. The regional Minister for Agriculture, Alessio Mammi, described the blue crab at today's release as one of the most serious crises to have struck the Adriatic in recent years, with significant consequences for a strategically important sector of the Emilia-Romagna economy. The traditional Adriatic cuisine, which relies heavily on clams, venus clams and mussels, is also feeling the loss. Without effective countermeasures, the Emilia-Romagna region warns that a profound crisis in shellfish farming in the upper Adriatic could materialise within a few years.
Why the octopus
The common octopus is, in nature, an excellent predator of crustaceans and one of the very few natural enemies of the blue crab present in the Adriatic in significant numbers. As the Italian newspaper Il Tempo quotes from the Askanews report, the researcher Antonio Casalini measured the predatory behaviour of the octopus in multi-year laboratory trials at the University of Bologna: a sub-adult octopus weighing 600 grams is capable of catching a blue crab weighing more than 400 grams. The octopus thus belongs to the few species native to the Mediterranean that hold a size advantage over the invasive crab.
The reproductive potential of the octopus is, admittedly, high, but its survival rate in the wild is very low. Of the 500,000 juvenile octopuses released, a large proportion will die within the first few weeks, whether through other predators, unfavourable sea currents or unsuitable seabed conditions. The scientists expect only a fraction of the released octopuses to reach the age at which they can hunt the blue crab effectively. The experiment is intended to establish whether that fraction is sufficient to control the crab population in the long term, without the need for annual new releases.
Riccione and Cesenatico: the two test areas
The choice of Riccione and Cesenatico as test areas follows a clear scientific logic. Both locations lie on the Adriatic coast of Emilia-Romagna, south of Milano Marittima, and are known for their long fishing tradition. Off Riccione, the artificial barrier originally constructed to combat coastal erosion has, over recent years, become a secondary reef with a species-rich flora and fauna in which octopuses have good chances of survival. Off Cesenatico, by contrast, the scientists first had to create artificial dens, as the seabed there is sandy and shallow.
Both test sites will be monitored over the coming months using underwater video cameras, net surveys and stock assessments. The first reliable results are expected in spring 2027, when the surviving octopuses will have reached adulthood and their predatory performance can be measured in the wild for the first time. As the regional newspaper Corriere Romagna documents in its coverage of today's release date, should the project prove successful, it is planned to extend to further stretches of coastline in Veneto, the Marche and Apulia, where the blue crab invasion has by now reached a similar scale.
What travellers in the Adriatic region can see and eat
For travellers visiting the Adriatic in the coming months, the Octo-Blu project has a number of practical implications. Along the shoreline itself, the releases are not visible, as the octopuses dive immediately into deeper waters. In the restaurants of coastal towns, the blue crab is appearing on menus with increasing frequency, as individual fishermen and chefs seek to make culinary use of the invasive species and thereby push back against the ecological pressure it creates. The flesh is considered flavoursome and is often served in the American style with butter, lemon and parsley, or used in soups and ragouts.
Those wishing to sample the classic mussel and clam dishes of the Adriatic should seek out established restaurants between Chioggia, Goro, Rimini and Cesenatico, where the ingredients still frequently come from small regional producers. The long-term survival of this cuisine depends critically on whether the Octo-Blu project or similar initiatives can restore the ecological balance of the northern Adriatic . In the years ahead, it will become clear whether the 500,000 octopuses off Riccione and Cesenatico represent the beginning of a new ecological reality, or whether they remain a scientifically ambitious episode with no lasting effect.
