Observations on the Frequency of Claw Loss in the Crayfish Procambarus charkii

Abstract

Abstract— The incidence of claw loss in the crayfish Procambarus clarkii was surveyed in two ponds. Pond 1 contained rice forage, and crayfish were trapped and removed three times per week. Pond C48 contained no supplemental forage, and no trapping occurred in the pond. In March claw loss in both ponds was similar with 87–91% of the population having both claws intact. Males and females showed no difference in the incidence of claw loss in either ponds. By May the abundant rice forage present in pond 1 during March had been depleted; however, the physical appearance of pond C48 changed little. In May claw loss was greater in pond 1 than pond C48; both males and females in pond 1 had a higher incidence of claw loss (increasing from 13% to 37%) than those in pond C48 (increasing from 9% to 17%). Claw loss in pond C48 males did not increase significantly; however, female claw loss increased approximately two‐fold. In May hepatopancreas water content was significantly higher for crayfish from pond 1 when compared to pond C48, suggesting lower energy reserves. During times of environmental stress, such as decreased food availability, decreased structure, low oxygen or temperature extremes, regeneration may influence energy allocation to growth and possibly reproduction, especially if energy reserves are low. Thus, information on the incidence of claw loss and energy reserves in crayfish exposed to different pond conditions may be useful in the design of management strategies.