Distribution and fecundity of the blue crab, Callinectes sapidus, in three lagoons of the Po River delta

The increasing introduction of non-indigenous species (NIS) into marine ecosystems poses significant ecological and economic challenges. Among these species, the Atlantic blue crab Callinectes sapidus (Rathbun 1896) has become a prominent invasive species in the Mediterranean Sea, particularly in the Po River Delta areas. This study aims to analyze the spatial distribution of C. sapidus in three lagoons of the Po delta: Scardovari, Barbamarco, and Canarin. Field sampling was used to collect data on population structure and seasonal variations. The second object of this study is to assess the fecundity through laboratory analysis in two different areas: the Po delta area and the south lagoon of Venice. Results indicate that C. sapidus exhibits a wide distribution of this species, suggesting a high degree of adaptability to the fluctuating environmental conditions of the lagoons, with a higher presence of male and mature individuals. Fecundity analyses revealed a high number of eggs, amounting to 2409759 for the Po delta area and 3439201 for the south lagoon of Venice. These findings provide crucial insights into the ecological impact of C. sapidus in non-native habitats and can contribute to the development of management strategies aimed at mitigating its effects on local biodiversity. Further research is necessary to refine predictive models of its population dynamics and assess long-term ecological consequences.