Authors
Russell Lande, Steinar Engen, Bernt-Erik Saether
Publication date
1995/5/1
Journal
The American Naturalist
Volume
145
Issue
5
Pages
728-745
Publisher
University of Chicago Press
Description
Optimal harvesting theories based on the concept of maximum sustained yield assume a stationary distribution of population size, ignoring that extinction is the eventual fate of all populations. We analyze the dynamics of populations at risk of extinction from demographic and environmental stochasticity as well as harvesting. Diffusion theory is used to derive approximate formulas for the mean time to extinction, T, the expected cumulative harvest before extinction, Y, and the mean and standard deviation of annual harvest, ȳ and σy. In numerical examples we compare the performance of different harvesting strategies in terms of these statistics. We derive optimal harvesting strategies that maximize Y or ȳ. The optimal strategies always involve a threshold function in which harvesting occurs at the maximum possible rate above a critical population size, c, with no harvest below c. For a broad class of stochastic …
Total citations
19951996199719981999200020012002200320042005200620072008200920102011201220132014201520162017201820192020202120222023202414515899116109495787241071391115810965
Scholar articles