RICHMOND, VA. — The Department of Environmental Quality and the Department of Game and Inland Fisheries continue to track and investigate springtime fish disease and mortality events that have occurred in several rivers in the western part of Virginia in recent years. Only a few isolated problems have been reported to date this spring, but as the period begins when these events have occurred in past years, the state agencies are enhancing their investigation by seeking input from the public.
Since 2004, fish disease outbreaks and mortality have occurred in the Shenandoah River basin. In spring 2007 similar events began in the upper James and Cowpasture rivers. The impacts appear to be most severe among smallmouth bass and sunfish, although other types of fish also have been affected. Outbreaks often are accompanied by open sores, or skin lesions, in many of the diseased fish. Typically these events have begun in the spring when water temperatures rise into the 50s and have continued until water temperatures reach the mid-70s, generally running from early April until mid-May.
In 2005, DEQ and DGIF formed the Shenandoah River Fish Kill Task Force, a group of stakeholders, including university and government scientists, environmental groups, fishing guides, and volunteer monitors – all with the goal of finding the cause of the annual spring die-off events. This coordinated approach helped state agencies set priorities, identify, conduct and evaluate research into causes of the springtime outbreaks.
Studies by state and federal scientists and several university researchers have focused on water chemistry, general health of fish and other aquatic life, and fish diseases. Water quality studies to date have not identified any individual chemicals at levels that would be expected to cause fish disease or mortality. Fish health studies indicate that fish are subjected to multiple stresses, with evidence of damaged skin, gills and internal organs. Fish appear to have a high number of internal parasites, and a high prevalence of a condition called fish intersex also has been observed in some species.
Biological pathogens, especially bacterial fish diseases, have come under greater focus during the past two years. Initial findings suggest links between certain bacteria and the disease outbreaks. Ongoing studies involving DEQ, DGIF and the U.S. Geological Survey’s Leetown, W. Va., Science Center, continue to explore the role of bacterial communities, along with environmental and contaminant factors that may cause immune suppression.
The public has made a significant difference in this investigation. State officials and environmental leaders have learned of many of these outbreaks from reports provided by fishermen, land owners and other river users. Knowing the timing and distribution of these events will help scientists focus on the areas where incidents are active, and will help generate the most meaningful data. This information also allows DEQ and DGIF to post current information on locations and severity of fish disease and mortality and share this information with the public through updates on the agency websites.
The public is encouraged to continue to provide reports on observations of diseased, dying or dead fish. Helpful information includes location, date, unusual water conditions, types and numbers of fish, and photographs. Anyone with information on dead or dying fish is encouraged to contact the DEQ regional office in Harrisonburg at (540) 574-7800, or toll-free in Virginia at 1-800-592-5482. Information also can be emailed to email@example.com.
via Virginia DEQ