Comparison of Two Methods Used by Divers for Sampling Benthic Invertebrates in Deep Rivers

Abstract

A modified Hess sampler was developed to estimate standing crop and was compared with rock-filled basket samplers. The baskets, although biased for some invertebrates, consistently collected more individuals and taxa. Both methods showed high efficiency, as measured by the coefficient of variation, which generally decreased with increasing pollution. The relative proportions of each invertebrate group collected by each method were similar in many instances and each method was shown to be appropriate in deep-water situations, depending upon the goal of the study. Key words: invertebrate, sampling, river, artificial substrates, divers