Measures of concentration taken from industrial economics are used to
provide a measure of the dispersion of national fleet revenue among co
ntributing 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 speci
es 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 n
umbers of species. It is concluded that both statistics contribute to
describing the degree of dependence on a number of species within a fi
shery. (C) 1998 Elsevier Science Ltd, Ail rights reserved.