Comparison of two bioassessment protocols in five Georgia streams

We compared two stream water quality biomonitoring methods used by the environmental agencies of the state of Georgia. One uses fish communities; the other uses benthic macroinvertebrate populations. Five wadeable streams of varying water quality, size, and impacts in the greater Atlanta area were selected as study sites at which both bioassessment protocols were carried out, along with a physical habitat assessment. To compare the protocols, we examined correlations between specified indices of stream health based on each protocol as well as correlations among their individual components. Although general classification of the five streams by the indices from the protocols was consistent, the indices for stream assessment themselves were not correlated. Furthermore, many component metrics were not correlated with their index, especially for the fish indices. As a result, these indices may need to be considered and modified to reflect properly stream impact and degradation.