The use of systems open to emigration for the study of population regulation: Bluegill.

• Main Author: Hill, Jeffrey Phillips.
• Other Authors: Matter, William J.
• Language: en
• Published: The University of Arizona. 1990
• Subjects: Biology
• Online Access: http://hdl.handle.net/10150/185053

Experiments with bluegill (Lepomis macrochirus) were conducted using the open system proposed by Matter et al. (1989) to examine factors that influence animal residency in these systems. Tests of the exits from the system suggested that they accurately identified resident and emigrant animals. The food and cover provided were shown to be appropriate and sufficient resources for bluegill. Shade covers and initial closure of exit used by Bianchi (1984) were unnecessary to achieve animal residency. The number of resident fish at a fixed level of resources fluctuated widely due to some undetermined and uncontrolled environmental conditions. These results indicate that falsification tests of hypothesized mechanisms of population regulation in open systems, may not be conclusive unless all possible confounding variables can be excluded.