PROBLEMS CONTINUE ON POTOMAC AND SHENANDOAH WATERSHED
Stephen Reeser, a VDGIF district biologist and co-chair of the Shenandoah Fish Kill Task Force, gives the latest on the most troubled watershed in Virginia.

"We (Shenandoah Fish Kill Task Force) have been collecting fish from the North Fork, South Fork and Main Shenandoah and doing intensive health analysis on these fish," Reeser said. "We have focused on adult smallmouth bass and redbreast sunfish, but have also done some health work on other species. This work, being conducted by the USGS Science Center in Leetown, West Virginia, is focused on histopathology and is looking for signs of stress or poor health as well as measuring the immune system strength of these fish.

"We have also had fish tested for known viruses and bacterial infections by the USFWS Fish Health Lab in Lamar, Pennsylvania. A complete analysis and report of health work completed to date is not yet available. I can say that all of our fish have tested negative for any known fish viruses. The USGS folks are also doing similar fish health investigations in West Virginia and Maryland in the Potomac Watershed."

Reeser explained that the system experienced some fish kills, mostly involving adult smallmouths and redbreast sunfish, in March and April in the lower half of the North Fork Shenandoah (downstream of Woodstock) and a smaller kill in the South River. A kill involving northern hogsuckers occurred in late May on the Main Stem in Clarke County, and no explanation currently exists.

The biologist related that the VDGIF has not seen any measurable mortality of fish in the South Fork Shenandoah in 2006. However, reports came in that a small percentage of the adult smallmouths and sunfish had signs of stress, such as lesions and fin-rot. Also, the VDGIF has received reports of anglers catching a few adult smallmouths with lesions from the South Fork, North Fork, South River and North River.

Anglers are catching good numbers of smallmouths in the 9- to 10-inch range that are from the 2004 spawn, which survived the fish kills from the upper North Fork and South Fork.

"Overall, I would say that we have had a severe impact on the lower North Fork in 2006 and are still seeing signs of a stressed smallmouth and sunfish population throughout the watershed, based on a small percent of these species showing signs of lesions," Reeser said.

"My feeling is that we are dealing with possibly a compounding of multiple stressors. The river ecosystem and the effects within the watershed are extremely complex -- teasing out what is causing these fish kills is extremely difficult."

Riverkeeper Kelble emphasized that he has documented only approximately 10 percent of fry production in comparison with most years on the Shenandoah, partially because the most mature fish, the ones that know where and how to successfully spawn, are gone, mainly from the 2005 fish kill that took 80 percent of the adult smallmouths. He observed that the remaining barely mature fish, attempted repeatedly to spawn but with no success. The Main Stem saw virtually no reproduction.

"But perhaps more important than the low numbers of mature fish was sedimentation," Kelble said. "I did observe literally hundreds of nests which were abandoned without fry production, and I documented tremendous sediment and algal encroachment on these nests. Our low flows and high sediment load meant that most of the reliable spawning areas were unsuitable for nesting.