Bonytail (Gila elegans) may enhance survival of Razorback Suckers (Xyrauchen texanus) in rearing ponds by preying on exotic crayfish

摘要

This study examined the potential of bonytail (Gila elegans) to enhance survival of young razorback sucker (Xyrauchen texanus) in rearing ponds by serving as a biological control agent for young stages of Red Swamp Crayfish (Procambarus clarki). Large populations of crayfish in rearing ponds negatively affect the survival of razorback suckers, through predation and competition for food. Traps made with 6.34 mm (0.25 inch) mesh have been used in an effort to reduce crayfish populations, however crayfish less than 17 mm carapace length (CPL) are able to escape. Juvenile bonytail in experimental trials ate young crayfish ranging in size from 3 to 15 mm CPL. Crayfish consumption was not reduced in the presence of an alternative food source, but was reduced slightly by the presence of cover. These results suggest that juvenile bonytail may reduce numbers of crayfish smaller than 15 mm CPL in ponds used to rear razorback suckers. If so, integration of rearing programs for endangered razorback sucker and bonytail could have beneficial effects for both species.