By : Gamalat Y. Osman, Mansour A. Galal, Sherin K. Sheir* and Mona M. Soliman

Abstract

This study was designed to investigate the effect of starvation and drought on the adult Procumbarus clarkii. Samples were captured from the River Nile, Dakahleyia province, Egypt. Measurements were the animal weight and length and survival rate. The experiment was divided into four groups, control with food and water, starved with water only, drought with food only and starved – drought without any food or water groups. Crayfishes showed great tolerance for 14 weeks (P < 0.05). The body weight of the crayfish was more affected than the body and carapace lengths due to the loss of its chelae during starvation. In the starved groups, survival rate of the crayfish declined because its aggressive behavior such as killing each others (66.6%). Crayfishes could not tolerate drought for a long time (5 days). The body weight, length, and the carapace length were minimally influenced during drought, while the survival rate was dramatically affected within few days. The combined effect of both stressors affected the animal survival more drastically within four days (100, 50 and 0%). It can be concluded that starvation and drought caused serious changes in P. clarkii behavior, biometry and survival rate, which determine the ability of crayfish to adapt to one or more of the environmental changes.

2. Effect of starvation and drought on the activity of the freshwater crayfish, Procambarus clarkii.
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