Life-history traits of an invasive Mediterranean population of Callinectes sapidus integrated analysis of growth, age, and reproduction

Understanding the life-history characteristics of invasive populations is important for predicting population dynamics and informing management decisions. Specifically, the reproductive biology and growth of the invasive blue crab Callinectes sapidus were investigated in Sardinian lagoons. A total of 269 blue crabs, 149 females (carapace width CW 70.3-194.3 mm) and 120 males (CW 57.1-208.8 mm) were sampled between 2023 and 2025. Six macroscopic gonadal maturity stages and three histologically validated embryonic development stages were identified. Fecundity ranged from over 1.4 to over 10 million eggs per berried female. Gonado-somatic Index values peaked in spring and summer, and berried females were more abundant in summer, indicating a main reproductive period during the warmer months. The size at maturity was estimated at 132.4 mm CW for females. Growth was estimated for the first time through direct counts of growth bands in gastric mill ossicles. Among the examined structures, the zygocardiac ossicle provided the most reliable results (% agreement = 78%), with 0–4 growth bands observed in both sexes. Age–length data fitted the von Bertalanffy model (CW∞ = 175.23 mm; k = 0.65; t0 = −1.02). These findings provide useful information to a better understanding this invasive species life-history traits.