Triploid grass carp are sterile, weed eating fish that often provide effective control of unwanted aquatic vegetation in ponds and lakes.

NC Administrative Code (15A NCAC 10C .0211 POSSESSION OF CERTAIN FISHES) allows triploid grass carp certified to be sterile to be bought, possessed and stocked locally for control of aquatic vegetation under a permit issued by the NC Wildlife Resources Commission.

Grass carp is an exotic species that can have unintended impacts on desirable aquatic vegetation within the waters stocked as well as adjacent waters if the grass carp escape. Aquatic vegetation provides valuable habitat to game and nongame fishes.

Inland, public fishing waters – Anyone stocking public waters must apply for a permit from the NC Wildlife Resources Commission.

Private ponds – The North Carolina Wildlife Resources Commission authorizes the private pond owner to use the receipt from a licensed triploid grass carp distributor as their stocking permit if all the following conditions apply:

• Triploid grass carp are being stocked in a private pond. Pursuant to 15A NCAC 10C .0102, a private pond is a body of water arising within and lying wholly upon the lands of a single owner or a single group of joint owners or tenants in common, and from which fish cannot escape, and into which fish of legal size cannot enter from public waters at any time. This does not include any impoundment located on land owned by a public body or governmental entity.
   
• The private pond is less than 10-acres.
   
• The private pond is being stocked with no more than 150 triploid grass carp. At a stocking rate of 15 fish per acre of water, 150 triploid grass carp are adequate to control vegetation in a 10-acre pond.

 

Anyone wanting to purchase more than 150 triploid grass carp or stock a pond greater than 10 acres must apply for a permit.

1. Before applying for a permit, applicants are encouraged to contact the fisheries biologist in their district to discuss the proposed stocking. See the Districts Biologists Map (pdf – opens new window) for contact information.
2. Please enter information into the Application (pdf - opens new window) to Stock Triploid Grass Carp online, print, and sign. For assistance in determining if a permit is required for a specific body of water, contact the district fisheries biologist located in your area.
3. Submit the signed application to the fisheries biologist in the district in which the body of water you’re interested in stocking is located.

Upon receiving the application, the fisheries biologist in your district, along with regional and state fisheries personnel, will review the proposed request and its potential impacts to the existing fish community, other aquatic organisms, and aquatic habitat in the water body to be stocked as well as downstream. Once a thorough review of the proposed stocking has been completed, the chief of the Division of Inland Fisheries will send you a written response.

You should receive a written response within 60 days.

There is no fee associated with the permit application review or issuance.

A source list of licensed triploid grass carp distributors is available from the NC Department of Agriculture.

The price of grass carp varies with the current supply and demand. Contact a licensed triploid grass carp distributor for a quote.

In most waters, a stocking rate of 10-15 fish per surface acre of water will result in control of unwanted vegetation. The ultimate level of control will depend on the type and amount of vegetation present.

Grass carp are susceptible to predation by predatory fish and fish-eating birds. For this reason, stocking larger fingerlings (9 inches or greater) is usually more successful in ponds and lakes where largemouth bass and other predators are present. Stocking smaller fingerlings in August when aquatic vegetation is most dense may allow sufficient survival and growth for the triploid grass carp to control the vegetation in the succeeding year.

Vegetation identification information is available through N.C. State University and the N.C. Division of Water Resources – Aquatic Weed Control Program.

Private pond owners can also contact the Agricultural Extension Service in their county for additional assistance.

Triploid grass carp are an effective control agent for the following species of aquatic plants: hydrilla, chara, elodea, widgeongrass, bladderwort, fanwort, coontail, pond weed (potamogeton), naiads, parrotsfeather and duckweed. These plants are generally described as submerged or floating aquatics with filamentous, relatively delicate stems.

Triploid grass carp are not effective in controlling the following plants: eelgrass, Eurasian watermilfoil, smartweed, stonewort, water hyacinth, American lotus, yellow waterlily, fragrant waterlily, maidencane, dollarweed, alligatorweed, torpedograss, and cattails. These plants are generally characterized as emergent or floating aquatics with sturdy, vascular stems. Grass carp are not recommended for control of these species.

The total elimination of all rooted aquatic vegetation from a pond or lake is not desirable. Vegetation provides valuable habitat that serves as nursery areas, refuges for small fish, and foraging areas. Eliminating this habitat can alter the ecological balance of a water body.

If all rooted vegetation is removed, it is probable that nutrients may express themselves in undesirable vegetation forms, such as dense blue-green or filamentous algal blooms. A body having algal blooms and no rooted aquatic vegetation is more likely to develop summer oxygen depletions that result in fish dieoffs.

Additional information is available through N.C. State University and the N.C. Division of Water Resources – Aquatic Weed Control Program.