The Stream Survey Team (SST) is a small group of technicians, biologists and seasonal workers who monitor the health of Georgia's wadeable streams by surveying fish communities. The abundance and diversity of fish species in a stream reflects the overall health of the stream and its fish and wildlife habitat.
History (where did we come from?)
Fisheries workers from the Fort Valley office sampled over 500 streams in west central Georgia in the early 1990s in an effort to relate fish community health to land use. Three years after this study was completed, the data were pulled into a lawsuit brought by several conservancy groups against the U. S. EPA. The conservancy groups successfully contended that EPA had not required Georgia's environmental regulatory agency, the Environmental Protection Division (EPD), to enforce the Clean Water Act of 1972 in regard to the states list of impaired waters. The lawsuit has become known as the TMDL (Total Maximum Daily Load) lawsuit. Most other states were affected by similar, also successful, lawsuits. One outcome of the Georgia lawsuit was that the streams found to have impaired fish communities during the Fort Valley land use study were added to EPD's 303d list of impaired waters. Another result of the lawsuit in Georgia was that EPD is now required to write a TMDL prescription for each of the impaired streams. This prescription estimates the maximum load of pollutants the stream can assimilate and allocates point and nonpoint source loads accordingly.
How does all of that relate to the work of the SST? The SST was established in 1997 and tasked with providing input to the TMDL process by assessing the biotic integrity of streams using fish as indicators. During SST's first two years (1998 and 1999), the primary job was to re-sample the streams found to be impaired in the early 1990s and to provide guidance to EPD as to whether or not those streams should be removed from their TMDL list. This work and other work completed during 1998 and 1999 took place in the Piedmont ecoregion of central Georgia. Since 1999 the SST has assessed streams throughout the state, from the Blue Ridge mountains to the coastal plain. Nearly 1500 stream surveys have been completed and the Georgia Fish Index of Biotic Integrity has been developed for four of Georgia's five major ecoregions.
Survey Techniques (what do we do?)
Wadeable streams are sampled primarily using backpack electrofishers, although a tow barge electrofisher is sometimes used in larger streams. With these electrofisher units, a low wattage electrical current is applied to the water, which temporarily stuns fish. Stunned fish are then netted and held in aerated live buckets until identified, sorted by species, counted, and released. As the SST program expands, it is hoped to develop techniques for doing Index of Biotic Integrity (IBI) assessments in larger streams and rivers by using boat-mounted electrofishers.
The primary technique being used to determine the quality of fish communities is called the Index of Biotic Integrity. This index uses the numbers and types of fish species present in a stream to produce a stream score or rating for comparison across streams within a particular ecoregion or to 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.