PCB uptake and transfer to humans by lake trout

Abstract

A mathematical model for contaminant uptake from food and water by fishes is combined with a model for yield as a function of fishing mortality in order to examine both the contaminant concentration in fishes and the amount of contaminant transferred to humans from fishes as functions of fishing mortality. The models are fitted to lake trout Salvelinus namaycush data from Lake Michigan, where there has been a persistent problem of PCB contamination. Transfer of contaminants from fishes to humans can be regulated through control of fishing. The concentration of contaminant decreases exponentially as fishing mortality increases because fishing reduces the number of older individuals in the population and concentration is a function of age. The amount of contaminant transferred from a fish population to humans increases to a maximum and then begins to decrease as fishing effort increases. The maximum rate of transfer occurs at a relatively low level of fishing.