From a fishing boat off the Adriatic Sea, Italian scientists successively released thousands of juvenile octopuses into the sea, in an effort to find ways to control the rapidly growing blue crab population and cause great damage to the aquaculture industry.
The project is implemented by a research group from the University of Bologna (Italy), with the expectation of using octopuses as a natural counterweight to blue crabs.
“We chose octopuses because in nature, they are formidable predators for crustaceans,” Antonio Casalini, a member of the research team, told AFP.
Blue crabs originate from the Atlantic coast of North America and appeared in the Mediterranean decades ago, possibly following transport ships here through braising water.
In recent years, the number of blue crabs has increased sharply. The Italian government and fishing organizations believe that warming sea levels and climate change may contribute to promoting the development of this species.
With strong and sharp claws, blue crabs can easily break the shells of mollusks, causing serious damage in northeastern Italy - one of the largest clam production areas in Europe.
The Emilia-Romagna regional government said that blue crabs have caused damage of nearly 17 million euros (about 20 million USD) in the locality since 2022. The Coldiretti Agriculture and Fisheries Organization also estimates damage across Italy at about 200 million euros (about 233 million USD).
A fisherman who also raises clams participating in the Davide Sanulli project said that blue crabs eat everything, including young clams from the seabed.
The project named "Octo-Blu" has been implemented since last year with funding from the Emilia-Romagna region, aiming to increase the number of octopuses and create more natural predators for green crabs.
At a laboratory in the port city of Cesenatico, researchers raised juvenile octopuses in a water tank. When they reached a suitable size, they were taken to the sea and released in areas near underwater reefs, where artificial shelters made of cement and clay were arranged.
About 80,000 octopuses have been released since June. The research team aims to double this number by the end of August, hoping that some of them will develop into adult octopuses.
The goal is to form a small population near the shore so that they can contribute to controlling the spread of blue crabs," Casalini said.
However, scientists admit that octopus is not the only solution. This species does not tend to live in shallow, warm and sandy waters - the characteristic environment of lagoons, where blue crabs cause the most serious damage.
The research group at the University of Bologna is considering the possibility of incorporating other predators, including grouper and eel. Scientists expect that the exploitation of many natural predators may contribute to limiting blue crabs, thereby reducing pressure on the marine ecosystem and the Adriatic coastal fisheries industry.
