Similar to the development of water quality criteria, many states are developing state-wide biological databases for fish and invertebrates. These databases are often used to determine a desired biological community attribute (e.g., maintain a certain number of species) that sets the bar against which other biological communities can be compared, enabling a biological criterion to be met. This is an emerging concept being applied thus far in several states to-date, including Ohio, Maine, and North Carolina.

GEI has remained a leader in the use and development of biological measures (metrics) for use in biocriteria and the assessment of the health of aquatic systems. Our long-term bioassessment studies provide a unique database for validation of biological metrics and biocriteria proposed by regulatory agencies, allowing us to ensure our clients understand and comply with such guidance when applied to their site.