Tidal Index of Biotic Integrity for the Texas Coast

Tidal streams on the Texas coast are frequently listed on the 303(d) List of Impaired Water Bodies for depressed dissolved oxygen. Depressed dissolved oxygen is a natural condition in warm, low gradient streams and preliminary data suggests this may be the case for some streams along the Texas coast. Currently there is no metric for measuring the biological community in tidal systems and therefore no mechanism for determining if a new dissolved oxygen criterion is appropriate for the presumed aquatic life use. Developing an index of biotic integrity (IBI) for tidal streams would allow for the evaluation of biological communities in brackish waters. The study will include characterizing fish and benthic macro invertebrate communities at both stressed and reference sites along the Texas coast. Community metrics will be used to test an IBI that can be used by the TCEQ for coastal regions.