Fish Community Biomonitoring Standard Operating Procedures and Scoring Criteria

Fish Community Biomonitoring

The Georgia Department of Natural Resources, Wildlife Resources Division (WRD) Stream Survey Team (SST) is a small group of biologists, technicians, and seasonal workers who monitor the health of Georgia's wadeable streams by surveying fish communities. The abundance and diversity of Georgia’s fish species reflect the overall health of the stream and its habitat. WRD provides fish community health data to the Georgia Environmental Protection Division (EPD) for incorporation into the biennial assessment of water quality known as the 305(b)/303(d) Integrated Report.

Certain communities that hold National Pollutant Discharge Elimination System (NPDES) permits to discharge treated wastewater into State waters are required to monitor fish community health as a part of the Watershed Assessment and Watershed Protection Plan implementation process.

Fish Survey Techniques

Wadeable streams are sampled primarily using backpack electrofishers, although a tow barge electrofisher may be used in larger streams. With these electrofisher units, a low wattage electrical current is applied to the water that temporarily stuns fish. Stunned fish are then netted and held in aerated live buckets until identified, sorted by species, counted, and released.

The primary technique used to determine the quality of fish communities is called the Index of Biotic Integrity (IBI). This index uses the numbers and types of fish species present in a stream to produce a score or rating for comparison across streams within a particular ecoregion or in the same stream over time.  Additionally, habitat availability and water quality are measured to help explain similarities or differences in IBI scores among streams. This IBI work allows relevant and consistent evaluation of stream health across the state while providing a much-needed database of fish distribution records.  To date, the Georgia Fish IBI has been developed for four of Georgia's major ecoregions including the Ridge & Valley, Blue Ridge, Piedmont, and Southeastern Plains. The Southern Coastal Plain ecoregion continues to be studied for future IBI development.

Standard Operating Procedures and Scoring Criteria

Standard operating procedures (SOP), sampling protocols, and scoring criteria have been developed for several ecoregions in Georgia by the Georgia Department of Natural Resources, Wildlife Resources Division, Fisheries Management Section.

In 2020, the scoring criteria were updated to incorporate all WRD fish data collected through 2018 into individual metric datasets.  The scoring criteria trisection breakpoint lines and associated equations for the species richness metrics (#1-6) were updated and the fish lists and associated tolerance and trophic categories for each ecoregion/river basin combination were revised.

The January 2020 WRD Fish Community Biomonitoring SOP and Scoring Criteria documents are linked below: