Effect of Temperature and Salinity on Size at Maturity of Female Blue Crabs

Abstract

Otter trawls and gill nets were used to collect 15,517 female blue crabs from nine Texas bay systems during 1984–1987. Carapace width, water temperature, salinity, and maturity stage were recorded for each blue crab. Logistic regression revealed that carapace width, salinity, and temperature were significant predictors of maturity. The logistic model is accurate, correctly predicting maturity stage 92.7% of the time. Probability of maturity increases with increasing carapace width; crabs mature at smaller sizes as temperature and salinity increase. At 25°C, size at 50% maturity is 138 mm at 0‰, 129 mm at 10‰, 121 mm at 20‰, and 112 mm at 30‰. At 20‰ salinity, size at 50% maturity is 139 mm at 10°C, 127 mm at 20°C, and 114 mm at 30°C. Results demonstrate the importance of including environmental factors in estimating and using blue crab life history parameters.