Shenandoah Valley, VA -- A persistent fish kill has severely reduced the adult smallmouth bass and redbreast sunfish population in over 100 miles of the South Fork and
Mainstem Shenandoah River. Fisheries biologists estimate that 80% of the adult smallmouth bass and redbreast sunfish have died as a result of this fish kill. A more precise estimate on the fish loss will be made this fall as agency personnel compare population numbers with historic data from previous years. Impacts on other fish species in the river appear to be minimal. The good news is that young smallmouth bass and redbreast sunfish have not been affected by this episode.
Fish began exhibiting bacterial lesions (sores) and dying in late April following significant rain events. The majority of the fish mortalities occurred in the following weeks. The bacterial lesions were a secondary effect. The lesions on the fish have been associated with natural bacteria found in the river, but the underlying cause appears to be an unidentified stressor, which compromises the fish's resistance and make them susceptible to bacterial infection.
Similar fish kills involving the same species occurred on the South Branch Potomac River (WV) in 2002 and on the North Fork Shenandoah River in 2004. The cause of those two fish kills was never determined. However, similar land use within these three Potomac watersheds may suggest a link between the fish kills. Fish have been collected and sent to laboratories at Virginia Tech and the U. S. Fish and Wildlife Fish Disease Lab in Lamar, Pa. for analysis. No signs of viral infections were found and external lesions were consistent with some type of stressor.
Although the exact cause of these fish kill may never be proven, fisheries biologists with the Virginia Department of Game and Inland Fisheries (VDGIF) continue to work closely with the Department of Environmental Quality to investigate several scenarios. The most plausible of these scenarios would suggest that several natural environmental factors combined with water quality impacts associated with excess nutrients might be the culprit. Water quality standards for nutrients that can affect stream health do not generally apply in Virginia. However, the scientific community generally agrees that elevated levels of nitrogen and phosphorous can impair freshwater ecosystems. Many tributaries of the South Fork Shenandoah suffer from nutrient overload, which can cause algal blooms and excessive aquatic weed growth, which at times can degrade water quality and stress fish. To further complicate issues, streambank erosion, runoff from parking lots, rooftops, roads, and pesticide/herbicide runoff can also negatively contribute to stream health. Teasing out one cause for the fish kill is very difficult and complex.
Smallmouth bass in the Shenandoah River grow extremely slow and live a long time. Replacing the quality size smallmouth that have perished will take 5-10 years. However, the 2004 spawn of smallmouth bass is one of the largest ever recorded and these fish were not impacted by the kill. Based on spring/summer flows VDGIF fisheries biologists expect a good spawn this year as well, but will not be able to confirm the level of spawning success until fall. These young fish form a good basis for population recovery, but the quality fishery will not return if fish kills of this nature persist in the immediate future.
What can be done to prevent this from happening in the future? VDGIF encourages all citizens living in the Shenandoah Valley to work together to reduce nutrient runoff. One of the most effective ways to improve water quality is to restore vegetated buffer zones along all streams and drainages in the watershed. These riparian zones are natural filters that help remove excess nutrients, sediment, and other pollutants from the Commonwealths waterways. There are several programs available that provide financial and technical assistance to landowners in restoring these buffer zones. Interested landowners should contact their Soil and Water Conservation District, the Natural Resource Conservation Service or the Virginia Department of Game and Inland Fisheries to discuss potential programs and financial incentives."
by the Board of Directors, Friends of the North Fork Shenandoah River
The Friends of the North Fork Shenandoah River commends the organizers of this meeting for providing an excellent opportunity to focus attention on the massive fish kills in the North and South Forks and the main stem of the Shenandoah River in 2004 and 2005.
Fisheries biologists estimate that 80% of the adult smallmouth bass and redbreast sunfish in the South Fork died as a result of the 2005 fish kill. The fish population will take years to recover and this will only happen if a recurrence is prevented. However, a recurrence cannot be prevented until the cause of this massive fish kill is identified and eliminated.
These basin-wide fish kills are serious and worrisome events. They not only cause great concern and economic harm in the sports fishing community. They have serious implications for the health of the river and the potential health impacts to those exposed to the river -- including people and livestock. Something dire is happening to our river. We do not know its extent nor its broader implications for the ecosystem of the river and the people who swim, fish and canoe on the river or who obtain their drinking water from the river.
We can return to a healthier river by preventing the recurrence of these fish kills. But this is only possible if we understand them.
To learn how to prevent recurring fish kills will take a carefully-crafted, well-funded research program with appropriate leadership and coordination. The Shenandoah River Fish Kill Task Force is well on its way to delineating the intensive water quality and ecological monitoring that is needed as well as a team of premier environmental research scientists who would be capable of tackling the problem. That research will cost on the order of $500,000 and the research needs to be launched by spring 2006. Unfortunately, funding of this research is still lacking. The state has committed funds for only a small portion of the effort and the Task Force will not be successful without a greater and immediate commitment of funds.
We ask all who care about this great river to join with us in telling our local, state and federal representatives to support this very important effort and to provide the necessary resources and leadership for this research program. Not to do so risks not only the loss of the vibrant fishery we have consistently enjoyed on both Forks of this historic and beautiful river. If we do not act, the Shenandoah River will remain a river in decline.
