Biological Assessment

The Montana Water Trust biologic monitoring program assesses the biological response of instream flow transactions. Biological assessment techniques provide an overview of the aquatic health of the ecosystem. The following provides a discussion of the equipment and methodologies currently implemented:

Underwater Census-Snorkeling:
This assessment is an underwater census that measures fish populations by snorkeling a selected reach to produce cost-effective, non-invasive results. The Montana Water Trust has received snorkel training from experienced professionals. The design of the snorkel methodology depends on the objectives of each transaction and is project specific.

Redd Counts-Spawner Surveys:
Redd counts, or spawner surveys, are an above-water survey to detect the presence of spawning adult fish. Redds are generally located in cool, clean flowing water in a riffle habitat. They are identified as an area with clean gravel, variable in size- depending upon the fish species. The Montana Water Trust applies redd counts on project streams that are recognized as spawning tributaries to larger systems.

Fish Traps:
The Montana Water Trust will apply fish trapping methodologies to assess the use of project streams by migratory species. The application of fish traps will be project and species specific. A permit must be obtained through Montana Fish Wildlife and Parks before using fish traps, and the traps must be continually monitored.