Regional and Temporal Variation in Size at Maturity of Female Blue Crabs (Callinectes sapidus) in Texas Coastal Waters

From 2006 to 2014, Texas Parks and Wildlife Department (TPWD) personnel collected size and maturity data from female Blue Crabs in all bays along the Texas coast.  Logistic regression revealed that coast wide size at maturity was negatively impacted by salinity, but that temperature had no effect. More specifically the model estimated that coast wide size at 50% maturity was 130.5 mm (95% confidence interval, 127.9-133.1) at 0 ppt, 124.4 mm (122.7-126.0) at 10 ppt, 118.2 mm (117.1-119.3) at 20 ppt, and 112.1 mm (110.6-113.5) at 30 ppt.  Size at maturity was found to vary substantially among bay systems in addition to the significance of environmental parameters on this relationship.  Finally, size at maturity was found to have decreased slightly from a similar study conducted by TPWD personnel from 1984-1987, though this decrease may not be biologically significant. Regardless of the driver behind these trends, the present analysis and explicit comparison of these results to a previous study suggests that Blue Crabs along the Texas coast are highly plastic in terms of size at maturity, especially spatially.  Coupled with decadal declines in Blue Crab populations, these results should justify conservative regulation by state management agencies in terms of spawner protection.