An Evaluation of 5.87-cm and 6.03-cm Escape Rings for Blue Crab Callinectes sapidus Traps

Escape rings are used in traps for blue crab Callinectes sapidus to reduce sublegal (<127 mm carapace width [CW]) catch. Two escape ring sizes (5.87 cm and 6.03 cm) were compared using laboratory-derived retention curves and catch data from control traps without rings and experimental traps with one of the two rings. Percent sublegal catch and large sublegal (117– 126 mm CW) catch per unit effort (CPUE) was significantly greater in traps with 5.87-cm rings than in traps with 6.03-cm rings. Catch per unit effort of legal (≥127 mm CW) blue crabs was not significantly different between the two experimental traps, although small legal (127–136 mm CW) CPUE was significantly lower in traps with 6.03 rings. The modal size of blue crabs increased from control traps to traps with 5.87-cm rings to traps with 6.03-cm rings. Retention curves by 5-mm size-groups corroborated trends depicted by field data. A lower retention of females than males was demonstrated. The larger escape ring was recommended to maximize the benefits of sublegal crab CPUE reduction.