Publication Abstract

Some Consequences of Size-Selective Harvesting on Fitness and on Yield

S.P. Blythe

A size-structured clonal model is formulated for a population subject to constant-fraction harvesting above a threshold individual weight, and with size-dependent fecundity and feeding. Individual fitness under a given harvesting regime is investigated using invasibility criteria, and it is shown that, for the model presented, adapting growth rate to maximize individual fitness corresponds to maximizing adult biomass. Variation of yield with harvesting regime and individual growth rate is considered. It is shown that an evolutionary stable optimal harvesting strategy exists, through appropriate variation of the threshold harvesting size, provided that the constant-fraction harvesting rate is low enough. Some consequences for long-term management of exploited populations are considered, and future developments outlined.

Reference:

S.P. Blythe, 1990. Some Consequences of Size-Selective Harvesting on Fitness and on Yield. IMA Journal of Mathematics and Applied Med Biology, 7: 41-53.