Stream monitoring: Fish

Many groups of organisms have been proposed as indicators of environmental quality. Ideally, a biological monitoring program will integrate multiple assemblages in order to better assess environmental quality.

Fish are one of the most widely used and useful organisms for measuring water resource quality. They are typically present even in the smallest streams and are easily sampled and identified with the proper equipment and training. The Clean Water Act mandates “fishable” waters and the public widely recognizes fish for their economic and aesthetic value.

Lake sturgeon sampled during electrofishing. For more information about fish, check out the Fishes of Minnesota website.

Fish are a diverse group of organisms and have a wide range of life history requirements. Some fish are sensitive to changes in water temperature, substrate composition, stream flow, or various water chemistry parameters, while others are tolerant of change in their environment. They occupy positions throughout the aquatic food web and characterize a range of trophic levels (planktivores, herbivores, omnivores, invertivores, piscivores). The structural and functional variety of fish communities make them excellent indicators of water quality and provide an integrated view of waterbody condition.

MPCA staff sampling fish.

The Minnesota Pollution Control Agency has been using fish community data to assess water resource quality for the last decade. In this period, IBI’s have been developed for streams in the Minnesota, Red, St. Croix, and Upper Mississippi River Basins. The objective is to develop biological criteria utilizing fish for all streams within Minnesota.

Biological assessments are used by Minnesota and many other states for several aspects of water resource management, including:

• Long term condition monitoring (status and trends)
• Aquatic life use assessment (305b)
• TMDL (303d) listing, de-listing, diagnostic, and effectiveness of implementation
• Problem investigation monitoring
• Effectiveness monitoring
• Issuing NPDES permits, 5 year review

Reports

• Conditions of Rivers and Streams in the St. Croix River Basin of Minnesota (wq-bsm2-01)  (file size=7 MB)
• Examining Relationships Among Stream Temperature Variables and Fish Community Attributes in Warmwater Streams of the Minnesota River Basin (wq-bsm2-02)
• Revisiting the Minnesota River Assessment Project (lrwq-s-2sy11)

Maps

MPCA Fish Community Sampling Stations in Minnesota

Standard operating procedures (SOPs)

• Reconnaissance Procedures for Initial Visit to Stream Monitoring Sites (sf-sop-recon)
• Fish Community Sampling Protocol for Stream Monitoring Sites (sf-sop-fish)
• MPCA Stream Habitat Assessment (MSHA) Protocol for Stream Monitoring Sites (wq-bsm3-02)
• Physical Habitat and Water Chemistry Assessment Protocol for Wadeable Stream Monitoring Sites (wq-bsm3-01)