The grass carp, also called white amur, is one of the largest members of the minnow family, and often reaches weights in excess of 25 pounds. White amurs are native to larger East Asian rivers with Pacific drainages, including their namesake, the Amur River on the Chinese-Siberian border. Introductions have expanded their range into over 50 countries and according to some researchers, at least 40 U.S. states.
The grass carp is related to both the common carp and goldfish, but do not have barbels around the mouth as the common carp do. They also have soft dorsal and anal fin rays rather than the spiny rays of common carp or goldfish. Their body shape resembles a large creek chub or common shiner. The color of the grass carp varies from grey to golden brown or bronze on the back, shading to white on the belly.
Sterile or triploid grass carp are the only type of grass carp that are legal to stock in New York State. Triploid grass carp are created by subjecting the fertilized eggs to high pressures or temperature shock. These procedures result in the retention of an extra chromosome set, rendering the fish incapable of producing viable young. The sterile or triploid offspring are identical to the fertile or diploid parents with the exception of this extra chromosome set.
The stocking of fertile or diploid grass carp is prohibited in New York State. This is due to concerns over the potential impact they may have on sensitive aquatic habitats if their reproduction is not controlled.
Stocking rates for grass carp need to be carefully assessed for each body of water. These fish have voracious appetites and overstocking can result in the removal of too much aquatic vegetation. If the grass carp consume too many plants, important habitat is destroyed, and sport fish populations can be adversely effected. Therefore it is recommended that aquatic vegetation be maintained at approximately 20-30% of the ponds surface area. Stocking rates will vary between 5 and 15 fish per acre depending on the amount and type of vegetation, depth and age of the pond, and the type of water supply feeding your pond.
A permit must be obtained from the New York State Dept. of Environmental Conservation before grass carp can be purchased or stocked. Applications are available through DEC Regional offices, or we can mail you a permit application. The DEC does not charge for the grass carp stocking permit. When you receive your permit (usually within 2 weeks of submitting your application) it will indicate the maximum number of fish you may purchase. This number is based on information you supply about your pond on the application.
When you purchase your grass carp they will average about 12 inches in length. They will grow about an inch per month during the summer season. By the first November they will be approximately 18 inches long. Winter survival rates are excellent providing depth, water movement, and oxygen levels are adequate. Your fish will normally live from 5 to 10 years in your pond. Future stockings are necessary as the fish age and eventually die. You will know when restocking is necessary because of the increase of aquatic vegetation in your pond.
Grass carp are stocked in the spring, approximately between April 15th and June 10th. We also have had good success with a fall stocking from September 1st through October 15th.