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What is the Stream Survey Team?
History (where did we come from?)From 1990 to 1993, fisheries workers from the Fort Valley office sampled over 500 streams in west central Georgia 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 (led by the Sierra Club) against the U. S. History (where did we come from?)
From 1990 to 1993, fisheries workers from the Fort Valley office sampled over 500 streams in west central Georgia 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 (led by the Sierra Club) 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 lawsuit, TMDL standing for Total Maximum Daily Load. Most other states have been impacted 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 EPDs 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 Stream Survey Team? The team 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 our first two years (1998 and 1999), our primary job was to re-sample the streams found to be impaired in the early 90s 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 region of central Georgia. In 2000, we worked below the fall line in the Southeastern Plains (or upper coastal plain). In 2001 and 2002 we worked primarily in the Ridge and Valley region of northwest Georgia, and in 2003 we returned to the Piedmont to focus on streams in highly urbanized areas. In 2004 we began work in the Blue Ridge Mountain region of northeast Georgia and that work continues in 2005. Future sampling will take us to southeast Georgia (Southern Coastal Plain ecoregion).
Survey Techniques (what do we do?)Wadeable streams throughout the state are sampled primarily using backpack electrofishers, although a tow barge electrofisher is sometimes utilized in larger streams. With these electrofisher units, we apply a low wattage electrical current 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. We also have the capability of expanding our work to include larger streams and rivers by using a boat-mounted electrofisher as the program expands.
The primary technique we are using to determine the quality of fish communities is called the Index of Biotic Integrity. This index utilizes 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, traditional physical and/or chemical parameters such as habitat availability and water quality are sampled in order to help explain why IBI scores are similar or differ among streams. At present, we have developed IBI ranges and habitat criteria for the Piedmont, Southeastern Plains, and Ridge and Valley ecoregions. Ultimately, fish IBI ranges and habitat criteria will be categorized for each ecoregion spanning the entire state. This work will allow relevant and consistent evaluation of stream health and will provide a much-needed database of fish distribution records in Georgia.
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