The Record of the Last Sturgeons Caught in the Po River (North Italy) Tells a Cautionary Tale of Reasons of Their Silent Disappearance

Three sturgeon species—the common European (A. sturio), beluga (H. huso), and Adriatic sturgeon (A. naccarii)—coexisted in the Po River Basin until the mid-1970s, representing centuries of bio-cultural heritage for northern Italy's riverine communities. Despite their historical and cultural significance, the dynamics of their decline remain undocumented in scientific literature. This study reconstructs the final chapter of natural sturgeon populations in the Po River through systematic analysis of quantitative data from 1970 to 1990, including catch records obtained during scientific monitoring campaigns, fish market auction records, gray literature, and interviews with veteran fishermen. Our findings reveal distinct extinction trajectories: the beluga sturgeon disappeared by 1974, while the last common sturgeon was captured in 1984. The Adriatic sturgeon showed greater resilience, persisting longer in the Po Delta with low but stable populations. Overfishing emerges as the primary driver of decline. Historical fishing practices targeted spawning migrations along the entire river course, while mechanization from the 1960s—motorized boats and nylon nets—intensified fishing pressure. Coastal trawling in the northwestern Adriatic further impacted anadromous species throughout their life cycle. The 1987 ministerial decree establishing a 100 cm minimum catch size came too late to prevent extinctions. This research establishes the first comprehensive baseline of pristine sturgeon populations in the Po River system, revealing how intensive exploitation dismantled centuries-old ecological and cultural relationships. These findings provide crucial historical context for ongoing restoration efforts and highlight the interdependence between functional river ecosystems and human societies.