Given one female blue crab can produce millions of eggs, a population explosion in the lagoons may have been inevitable in the new environment. No matter how they were introduced to the region, the blue crabs found a paradise in the delta’s lagoons.
“They completely destroy clam farms. They completely eat all the seeds, even larger Manila clams,” said Mattias Gaglio, an ecologist at the University of Ferrara. “They completely disrupt the ecological network.”
The two most affected sites are the Scardovari and Goro lagoons, which often comprise most of the country’s clam production in a year, Gaglio said. In the Goro region, he and his colleagues showed clam production fell to an average of 4,000 tons in 2024 — a 70% decline compared to the previous decade. The Scardovari lagoon reported annual harvests down from 4,800 tons to 340 tons since 2023.
But scientists say it will be difficult, if not impossible, to rid the Italian lagoons of the blue crabs.