Maximum harvest of a fish population that has the smallest impact on population biomass

The maximum sustainable yield (MSY) has been a useful concept in fishery population dynamics, but populations harvested by annual removal of the MSY become commercially extinct in a variable environment. In this study, a target point is obtained that maximizes yield while minimizing the impact of fishing on population biomass and that reduces the risk. Fishing mortality was expressed as pF(MSY), where p was a proportion, and the rate of population increase. biomass, and yield were found in terms of the proportion p. A p-value of 0.75 maximized yield, while maintaining biomass as high as possible for protection of the harvested population. At the target point of 0.75F(MSY), a small decrease in yield below the MSY resulted in a substantial increase in stock biomass. (C) 2002 Elsevier Science B.V. All rights reserved.