Employing Small Bodied Fish in a Weight-of-Evidence Approach to Discriminate Effects from Multiple Discharges

摘要

This study demonstrated the effectiveness of small bodied fish (longnose dace [Rhinichthys cataractae]) in effects monitoring studies. The main findings were: 1) the responses of the small-bodied fish mimicked those observed with large-bodied fish, and 2) these fish enabled us to further isolate the potential contributing sources of the observed effects in longnose sucker (Catostomus catostomus). This paper illustrates how a small bodied fish filled in an important gap in the overall weight-of-evidence approach to assessing potential impacts using representatives of multiple trophic levels (algae, benthic invertebrates, and fish). For example, the use of a small bodied fish proved to be very valuable in supporting the findings of the benthic algae and benthic invertebrate surveys, and helped to explain some of the responses observed in longnose sucker. At this study site, where previous observations were consistent with nutrient-enrichment, a multiple trophic level assessment was employed to separate the influence of a confounding discharge from a municipal wastewater treatment plant in a pulp mill effects study.