Rapid-response indicators of changes in resource state based on Mediterranean bottom-trawl surveys.

A method is proposed for developing operational indicators of resource state, with an example based on a set of 8 variables (mean abundance index in weight, mean body weight, median length, sex ratio, sex ratio by selected length class, mean and median female length at maturity, percentage of females at maturity) derived from surveys conducted in the Strait of Sicily (central Mediterranean Sea, 1994 2002) for six target species. The method combines univariate (kite diagrams, sphere displacement plots) and multivariate techniques (multi dimensional scaling).