Daily Weird News Report
An unusual marine experiment is underway in Italy’s Adriatic Sea: researchers are releasing young octopuses in the hope that they will eventually prey on invasive blue crabs.
The blue crabs, native to the Atlantic coast of the Americas, were likely introduced to the Mediterranean through ships’ ballast water. Although they were first observed in the region in the early 20th century, their numbers and range have increased sharply over the past decade, according to Smithsonian Magazine.
The crabs have damaged populations of mussels, clams, other crustaceans and fish. Their claws have also damaged fishing equipment. Italian experts estimated that the species caused about $116 million in economic losses in the country in 2024.
To investigate a possible biological response, the Emilia-Romagna regional government is funding Octo-Blu, a University of Bologna project launched in 2024. Researchers spent about two years studying interactions between common octopuses and blue crabs while developing methods to breed the octopuses in captivity.
The first hatchlings were released on June 11 and 17. Additional young octopuses, in their paralarval stage, were released the following month along with a female octopus. In total, at least 130,000 octopuses have entered the Adriatic, the magazine reported.
The idea is based partly on laboratory observations. Researchers saw young octopuses hunting blue crabs, including specimens weighing roughly one pound. An adult octopus could eventually consume as many as four blue crabs per day, although only about 1 percent of the millimeter-scale hatchlings are expected to survive to adulthood.
The strategy has significant uncertainties. Common octopuses do not typically live in the warm, sandy lagoon habitats where blue crabs are causing some of their greatest problems. Researchers say they are accounting for that issue, but an outside marine ecologist described the project as a carefully controlled pilot rather than a proven method of controlling the invasive species.
Over the coming months, the team will monitor the released animals through scuba surveys and reports from local fishers. Researchers hope to determine by the end of the year whether the octopuses have made any measurable difference to the blue crab population.
