NC Wildlife Resources Commission
Grass Carp Permitting Protocol for Lake Gaston
January, 2007


1. Target density (Number of grass carp per vegetated acre)
a. The target density should be established as part of the comprehensive and adaptive management plan (Managing Aquatic Plants in Lake Gaston, A Long-Term Action Plan).
b. The Technical Advisory Group should clearly define the role of grass carp within the context of the management strategy and recommend appropriate density. The most recent consensus is 10 fish/vegetated acre, which is consistent with values documented in fisheries literature.

2. Stocking rate (Number of grass carp permitted for stocking)
a. The number of grass carp at large in the lake at the end of a given year will be modeled using a standard cohort analysis based upon 20% annual mortality and 0% escapement.
b. The amount of hydrilla will be determined at the end of the growing season each year, and the acreage will be provided to the NCWRC.
c. The annual estimated density of grass carp will be calculated as the number of grass carp at large in the lake divided by the acreage of noxious weeds.
d. The number of grass carp permitted for stocking the following year will be calculated as the number of grass carp required to make up the difference between the target density and estimated density.
[(target density) - (estimated density)] × (acreage of noxious weeds)
If the estimated density is greater than or equal to the target density, no grass carp will be permitted for stocking.