Note: Since presentation of this plan in 2008, additional grass carp studies have led to increasing stocking rates to 18 grass carp per vegetated acre in 2012. This increase was supported by the LGA and the Lake Gaston Weed Control Council.
Lake Gaston is heavily utilized not only by lakeside property owners, but by anglers, boaters, and other visitors. Vegetation management activities have the potential to significantly affect (1) access to outdoor activities such as swimming, boating, skiing, and angling, (2) property values in and around the lake, (3) local businesses, (4) the county tax base, (5) water quality, (6) the environmental health of the system, and (7) tourism.
Hydrilla is a highly invasive aquatic weed, able to propagate by fragmentation, and through tuber and turion production. The Lake Gaston Association (LGA) recommends the use of triploid grass carp as the primary effort to control and/or eradicate the federally listed noxious aquatic weed hydrilla in Lake Gaston. Herbicide treatments will be used to supplement grass carp based on available funding.
No infested lake has ever successfully controlled hydrilla with herbicides alone. Herbicides are expensive. They are potentially dangerous, and therefore must be applied by a licensed applicator in accordance with the label.
Therefore, the LGA recommends stocking grass carp at a rate of 18 fish per vegetated acre of hydrilla, based on the Fall Total Lake Survey plus that acreage privately treated with contact herbicide. That the grass carp are a minimum of 12 inches in length and be widely distributed in several coves from bridges which would facilitate off loading. That future stocking be based on a total of 18 fish per vegetated acre until hydrilla is controlled without the excessive use of herbicides.
Herbicide treatment using public money will consist of only systemic herbicide treatments on hydrilla in coves where success of reducing the tuber count is achievable and multiple year treatments be applied to these coves in order to eliminate tuber count. Contact herbicide and algaecides using public money would be limited to public boat ramps, dry fire hydrants, and other invasive vegetation (i.e., Eurasian watermilfoil, Brazilian elodea, Lyngbya, etc). Since Eurasian watermilfoil is not the preferred food of grass carp, aggressive treatment of these areas with contact herbicide is recommended.
Definitions used in this plan
- Vegetated: The biomass of actively growing plants.
- Infested: The area where there are known hydrilla tubers.
- Acre: Unit of land measure equal to 43,560 sq ft (about an area 208 ft x 208 ft).
- Fall survey: The vegetated acreage of all aquatic plants in Lake Gaston