Describing benthic impacts of fish farming with fuzzy sets: theoretical background and analytic methods

Diver observations have been recorded over a period of several years at a site severely impacted by finfish mariculture. The logged data were analysed using fuzzy logic in order to address the problem of interpreting sometimes qualitative and subjective information. The underlying methodology based on fuzzy set theory is developed and described in this paper, along with the techniques used to quantify the relationship between the information recorded by the divers, which was usually of a verbal descriptive nature, and a numerical index of benthic impact. Fuzzy logic proved to be a valuable tool for translating the dive log data into quantitative form.