Factors affecting the daily movements of the crayfish Orconectes-virilis Decapoda Cambaridae
Surveys of the locations of marked crayfish and field experiments were conducted to determine factors affecting the daily movement of a stream population of O. virilis. Addition of artificial burrows did not affect the number of crayfish inhabiting a portion of the stream. Natural burrows from which the residents were removed were not fully reoccupied during that summer. Animals displaced to one portion of the stream showed no evidence of orientation to home areas. Experimentally changing the stream water level resulted in increased numbers of crayfish in the stream at night when the level was lowered and decreases when it was raised. Analysis of capture location data indicated that individual crayfish do not come out in the stream every night. When female crayfish have attached young, they move very little, move downstream just after the release of young and move upstream in the fall, as do males.