Lifetime reproductive potential of female blue crabs Callinectes sapidus in North Carolina, USA

Abstract

We examined lifetime clutch production and size at maturity for blue crabs Callinectes sapidus Rathbun in North Carolina, USA. Female crabs were collected at terminal molt and confined individually in the field for the duration of their lifetime. Crabs were monitored weekly for the pres- ence of eggs. Clutch quality and larval viability were assessed for each clutch. Crabs produced up to 7 clutches over 1 to 2 spawning seasons and survived up to 394 d after the terminal molt. Time to first clutch and time between clutches were positively correlated with carapace width and best described by degree-days, physiological time calculated as a thermal integral. Size at maturity was negatively correlated with water temperature on the day of the terminal molt. Egg lipid content (mean = 79.2% of dry mass), egg diameter (mean = 267.5 µm), larval carapace width (mean = 278.4 µm), and larval survival time without food (mean = 3.4 d) were similar for all clutches. The percentage of embryos developing normally decreased 40% from Clutch 1 to 4, and clutch volume decreased 50% from Clutch 1 to 5. Thus, most of a crab's reproductive output is from the first few clutches. Realistic esti- mates of fecundity and reproductive potential are essential for accurate spawning stock assessment and population modeling.