Response to Long-term Nutrient Deprivation and Recovery in the CrayfishesProcambarus clarkiiandProcambarus zonangulus: Oxygen Consumption and Metabolic Enzymes

Abstract

Procambarus clarkii (Girard) and Procambarus zonangulus (Hobbs) have adapted to dynamic environments that undergo regular thermal and hydrologic cycles, resulting in extended periods with limited food. To understand the strategy of adaptation to long-term food deprivation, oxygen consumption and activities of several metabolic enzymes were measured over a 5-mo period of starvation and subsequent 1 mo recovery period. There was no significant effect of starvation on oxygen consumption rate for P. clarkii. The oxygen consumption rate for P. zonangulus was significantly lower than fed controls at 4 and 5 mo of starvation. Enzyme activities in both species responded rapidly to starvation. There was a significant decrease in the activity of metabolic enzymes in the hepatopancreas and abdominal muscle of both species at 2 mo, suggesting metabolic rate depression at some level occurs within the first 2 mo of starvation. The decrease in enzyme activities in P. clarkii with starvation lagged slightly behind that of P. zonangulus. The strategy of P. clarkii is better suited to conditions where rapid emergence is required to compete successfully for limited resources; however, survivorship is reduced long-term. P. zonangulus’ ability to reduce metabolic rate may enhance long-term survivorship when emergence is delayed.