Dispersion of revenue in mixed fisheries

Measures of concentration taken from industrial economics are used to provide a measure of the dispersion of national fleet revenue among contributing species. The Gini coefficient and Herfindahl index provide a basic conceptual framework given variations in the number of species and their contribution. The paper analyses data for landings by species in a recent year in Denmark, France, Italy, the Netherlands and the United Kingdom. The Herfindahl index is considered as an alternative to adjusting the Gini Coefficient to allow for reliance on differing numbers of species. It is concluded that both statistics contribute to describing the degree of dependence on a number of species within a fishery.