An integrated ecological and biochemical approach to the management of the invasive blue crab Callinectes sapidus in a Po Delta lagoon

To optimize management of the invasive blue crab Callinectes sapidus in Mediterranean lagoons, this study presents an integrated analysis of population dynamics, stock status, and biomass valorization in Valle Fattibello (Northern Adriatic Sea). Reproductive dynamics exhibited a marked seasonal pattern; while male-biased sex ratios suggest migratory behavior, the recording of high lagoon salinities (37 PSU) and a summer peak in ovigerous females (>25–33%) indicate potential in-situ reproductive success. Growth trajectories were found to be significantly sex-specific, with males exhibiting faster growth rates toward smaller asymptotic sizes compared to females. Fishery analysis over 116 days yielded 16 tonnes of biomass, yet Catch Per Unit Effort (CPUE) showed high temporal variability. We identified salinity as the primary driver of catchability, signaling that environmentally standardized assessments are critical for reliable stock monitoring. Complementing the ecological data, biochemical profiling revealed that proximate composition and fatty acid profiles are subject to significant seasonal and sex-related shifts. High n-3/n-6 PUFA ratios and substantial yields of astaxanthin, chitin, and proteins underscore a high-value biorefinery potential. Ultimately, these findings support a transition toward sex- and environment-aware management frameworks that integrate invasive species mitigation with the industrial valorization of blue crab resources in the Po Delta region