Measuring the ecological and economic diversity of fish

Abstract

A new measure of fish biodiversity that captures not only the species’ number and abundance, but also its economic value is introduced. The measure is formulated by weighting the Simpson’s index with price. Its application to the traditional fisheries o f Lake Malawi reveals a decline in fish catch biodiversity. The decline is associated with a shift in fish catch from high valued to low valued species. Thus, this biodiversity measure can show the trend in fish biodiversity by using data on fish catch and price per species only. The availability of catch and price data for most fisheries makes this measure to be applicable as a monitoring indicator for the sustainable management o f fisheries.