Spotted Bass Habitat Evaluation Using an Unweighted Geometric Mean to Determine HSI Values

Abstract

Suitability Index (SI) curves developed by the U.S. Fish and Wildlife Service were used to evaluate habitat of adult spotted bass (Micropterus punctulatus) in riverine enviroments in northern Oklahoma. Reliability of suitability indices for individual variables appeared high. However, when the individual indices were aggregated into an overall habitat suitability index (HSI) by use of an unweighted geometric mean, correlations were low between HSI and species biomass. Accurate prediction of standing crop by aggregating individual suitability indices by an unweighted geometric mean appears to be unlikely. Rationale to explain failure of the geometric mean aggregation model is presented and an alternative procedure for predicting impacts is suggested.