Atlantic Blue Crab Invasion Collapses Manila Clam Fishery in Italy's Po Delta

The story of Oscarina Soncin and her fellow fishers in Italy's Scardovari lagoon is not a U.S. federal policy story — yet. The invasion of Atlantic blue crabs (Callinectes sapidus), native to U.S. waters, has collapsed the Manila clam fishery in the Po River Delta within three years, according to CNN and peer-reviewed studies in the research bundle. Fishers like Soncin, who once pulled up 1,100 pounds of clams daily, now are selling boats or retraining for other careers. The event is driven by a combination of warming Mediterranean waters and a lack of natural predators, not by any U.S. agency rule or congressional bill.

But the reframe for U.S. observers is this: the same species of blue crab is native to the U.S. Atlantic and Gulf coasts, and warming waters are already pushing species northward and disrupting domestic fisheries — as seen in the 2022 collapse of Alaska's snow crab fishery, attributed by NOAA to a marine heatwave (research bundle: NOAA feature story, October 2023). The U.S. lacks a comprehensive federal strategy for invasive species driven by climate change, relying instead on fragmented state-level responses and voluntary programs. A strong USDA and NOAA framework — including dedicated funding for early detection, rapid response, and economic relief for affected fishing communities — could help prevent an Italy-scale collapse domestically. Without it, small-scale fishers from the Chesapeake Bay to the Gulf of Mexico face the same vulnerability: a biological invasion, not a ballot box, deciding their livelihoods.