Blue crab: Italy releases 80,000 octopus hatchlings

Italian researchers have released about 80,000 common octopus hatchlings into the Adriatic Sea since June in a pilot project aimed at limiting invasive blue crabs that have damaged shellfish production in northeast Italy.

The University of Bologna team is breeding hatchlings in tanks at Cesenatico and releasing them near underwater reefs, where it has placed artificial dens made of cement and clay. The Octo-Blu project, launched last year and funded by the Emilia-Romagna region, aims to build a small near-shore octopus community that could prey on blue crabs.

Blue crabs are native to the North American Atlantic coast and arrived in the Mediterranean decades ago, likely via ballast water from ships. Their numbers have risen in recent years, and the Italian government and fishing groups have linked the increase to warmer waters and climate change.

Emilia-Romagna authorities said last year that blue crabs had caused almost €17 million ($20 million) in damage there since 2022. Farming and fishing group Coldiretti estimated damage across Italy at about €200 million, with Veneto also badly affected.

Researchers acknowledge limits to the octopus plan. The common octopus does not tend to live in the sandy, warm lagoon waters where blue crabs are causing the most damage. The Bologna team is also examining eels as a possible complement, while other experts have suggested seabass could be more effective against the crabs.