Invasive Species Devastate Clam Farms... Italy Releases 160,000 Octopuses

University of Bologna’s ‘Octo-Blu’ Project in Italy
Invasive Blue Crabs Devour Clams, Creating Trouble
Plan to Release 160,000 Octopuses in the Adriatic Sea

Italy is deploying 160,000 octopuses to combat the invasive blue crab species.

A photo to help understand the article, showing the appearance of the blue crab. Photo by Reuters and Yonhap News.

According to the U.S. science magazine Scientific American and the Associated Press on the 25th (local time), researchers from the University of Bologna and the government of Emilia-Romagna are carrying out the 'Octo-Blu' project in the Adriatic Sea of the Mediterranean. This involves releasing laboratory-hatched octopus larvae along the coast and installing artificial dens for them to settle in.

The blue crab is native to the Atlantic coast of North America. While considered a premium seafood along the U.S. mid-Atlantic coast and gaining interest in Korea for use in marinated crab dishes, it has become a nuisance in the Mediterranean, displacing local fish species and even forcing fishing operations to cease. The damage has been concentrated mainly in clam farms. The species can grow up to 1kg and is equipped with specialized claws adept at prying open shells, allowing it to devour clams and mussels indiscriminately. The northeastern region of Italy, known as Europe's largest clam-producing area, has been hit the hardest.

The monetary damage is also significant. According to Coldiretti, an Italian agricultural association, the total nationwide damage is estimated at around 200 million euros (about 322.7 billion won). The authorities in Emilia-Romagna reported that since 2022, damage within the region alone has reached 17 million euros (about 27.4 billion won). Local fisherman Davide Sanullini told the AP, “They consume every single juvenile clam that settles on the seafloor.”

Image to aid understanding of the article. Pixabay

The proposed solution is Italy’s native octopus. According to researchers, a fully-grown 1kg octopus can consume up to four medium-sized blue crabs per day under the right conditions. As part of the project that began in 2024, researchers have released laboratory-bred octopus larvae in Cesenatico and Riccione on the Adriatic coast, areas heavily populated by blue crabs. By June, 80,000 octopus had been released, and by the end of August, a further 80,000 will be added to reach a total of 160,000. Artificial dens made of cement and clay have been installed underwater near the release sites to provide the young octopuses with places to hide.

Antonio Casalini, a member of the research team, stated, “Instead of introducing a new species, the project aims to increase the population of native octopus that already inhabit the Adriatic Sea to naturally control the blue crab population.”

However, some marine ecologists have pointed out that the natural mortality rate for octopus larvae is as high as 99.9%, so the actual impact on population control may be limited. Another limitation is that octopuses are not well adapted to the warm, sandy mudflats where blue crabs are most concentrated. Addressing these concerns, Casalini explained, “Since a single female octopus can lay hundreds of thousands of eggs and has high reproductive potential, artificial releases can sufficiently help replenish the existing population.”

Other alternatives are also being discussed. Some experts suggest that European seabass may be more effective at controlling blue crabs. The Bologna research team is also considering eels, which favor crustacean eggs, as a complement to octopuses. In the long term, the team plans to continue releasing additional larvae and combine this with existing fisheries management policies to control the population.

This content was produced with the assistance of AI translation services.