JAMES P. BOHANNON AND MARK A. KONIKOFF, Department of Biology, University of Southwestern Louisiana, Lafayette, Louisiana 70504, USA

JAY V. HUNER, Crayfish Research Center, University of Southwestern Louisiana, Lafayette, Louisiana 70504, USA

The effects of two substrate types on water quality, adult female mortality, egg mortality, and hatching success were studied for two species of crawfish. Sexually mature females of Procambarus clarkii (Girard) and P. zonangulus Hobbs and Hobbs were placed in artificial burrows containing water only, silt and water, or clay and water. There was little difference in female mortality among the treatments. After 32 days in the burrows egg mortality was significantly lower for both species in the silt treatment. Burrows with clay did not significantly alter egg mortality. Of females laying eggs, egg mortality decreased from 78% in water to 17% in silt for P. zonangulus and 19% to 0% for P. clarkii. More P. clarkii females hatched juveniles than did P. zonangulus during the same period.