Agenda - 06-19-2012 - 8a - Laserfiche WebLink

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4 tributaries of the Eno River is not known, although it has been reported to be present in Sevenmile Creek. It was the consensus of the meeting attendees that the presence of hydrilla in a flowing water (lotic) system is fairly unique. Hydrilla Impacts Given the propensity for this invasive plant to dominate native aquatic plants to the point that these other plants are effectively eliminated, it is safe to say that hydrilla has infested the upper Eno River and is likely to continue to spread. Some meeting attendees think that hydrilla has surpassed the nuisance level in the Eno and now represents a serious threat the ecosystem of the river. Hydrilla infestation is problematic for several reasons: a) public perception, b) water quality impacts, and c) ecosystem impacts. According to the Superintendent of the ERSP, Keith Nealson, "Hydrilla is the number one resource management problem in the Eno; more so than water flow." He reported that during the summer, when hydrilla is widely abundant in the river, he receives many questions and complaints about the presence of the plant. Hydrilla is very unsightly in the river since it spreads widely and is highly visible. The plant also interferes with fishing such that the Eno is virtually "unfishable" from July to October. In general, hydrilla has a very negative impact on the recreational experience of visitors to the state park. Water quality in the Eno can be negatively impacted by the presence of hydrilla. During the summer months, when hydrilla is abundant in the river, the concentration of dissolved oxygen (DO) in the river can be reduced. The naturally occurring DO cycle can also be impacted on a daily and seasonal basis, as much lower DO concentrations than normal can occur at night during the summer months, and when hydrilla plants die in the late summer months, the decomposition of the plants consumes a great deal of DO. These processes negatively impact water quality and can cause fish kills in the river. Hydrilla can also cause ecosystem impacts. The Roanoke Bass (ambloplites cavifrons) is naturally found in only the Tar and Neuse River basins in North Carolina. The extent of these sunfish has been greatly reduced such that it is now listed as Significantly Rare by the NC Natural Heritage Program. NC Wildlife Resources Commission staff report that hydrilla in the Eno seems to be reducing the number of larger sized Roanoke Bass in the river. The longer term impact of hydrilla on the Roanoke Bass in the Eno is not currently known, nor whether or not hydrilla is impacting any other significant or endangered species that exist in the Eno River. In addition, a relatively new disease has been linked to hydrilla. Avian vacuolar myelinopathy (AVM) is a disease that has been found to affect the brain tissue of waterfowl in the southeastern US. Plant- eating waterfowl, including Canada geese and mallard ducks, become sick with AVM and die as a result of ingesting Orange County Department of Environment, Agriculture, Parks & Recreation PO Box 8181, Hillsborough, NC 27278 Phone: (919) 245 -2510 Fax: (919) 644 -3351