CHARACTERISTIC RETURN TIMES FOR HARVESTED POPULATION-MODELS WITH TIME LAG

The characteristic return time for a population model measures the time required for the system to return to equilibrium if perturbed. We show that for a one-dimensional model with a time lag an increase in the harvest rate (for constant-yield harvesting) or the harvest effort (for constant-effort harvesting) may produce a decrease in the characteristic return time. This depends on the nature of the model and the size of the time lag, and may give a means of testing the validity of models experimentally. © 1979.