The value of Pacific sardine as forage fish

This paper develops a simple bioeconomic model to investigate the economic and ecological issues associated with the commercial harvest of Pacific sardines relative to their value as forage for commercially, recreationally, and ecologically important predators in the California Current ecosystem. The model was used to evaluate how changes in the net per unit value of sardines, the net per unit value of sardine predators, and the transfer efficiency of predators affect the total net value of sardines, i.e. the net value of catches and the net value from sardine predation. Given recent market conditions for sardines and their commercial predators, and transfer efficiencies derived from predation data of the 1960s, it was found that the value of commercially caught predators and the efficiency by which they convert sardines to exploitable biomass were most important in determining the viability of the sardine fishery. The values assumed for predators that are not commercially caught were of no consequence under these conditions. Taking the value of sardines as forage into account does not necessarily mean an either-or situation for the fishery. As long as there is some measure of net value from the fishery and net value from predation, both benefit society at large.