A tiered aquatic life unit bioassessment model for Gulf of Mexico coastal streams

Document Type


Publication Date



© 2014 John Wiley & Sons Ltd. The tiered aquatic life unit (TALU) model allows quick and efficient bioassessment with goals that are based on practical, systematic sampling of commonly measured stream variables. A six-tier hybrid TALU model was developed as a proof of concept study for streams in six level IV ecoregions in the north-central Gulf of Mexico coastal plain. The model used in-stream habitat variables, land use, surveys of the unionid mussels, number of intolerant fish species and fish diversity in streams varying from 2nd through 6th order. The model classification identified sites considered a priori either as impaired or best available and minimised Type I (mistakenly concluding impairment) and Type II (failing to detect impairment) errors. The model also detected transitional sites, thereby illustrating incremental degradation or recovery, in contrast to previous monitoring tools focused on pass/fail approaches. Because the model classifies transitional sites and is easily modified to fit other ecoregions, it offers a useful foundation for resource managers to monitor the health of coastal plain rivers.

Publication Title

Fisheries Management and Ecology

This document is currently not available here.