Grass carp are a Chinese minnow that can easily grow to 50 to 75 pounds in a large lake; some have been know to grow even larger. Grass carp were introduced to American lakes in the 1970s as a way to control unwanted vegetation. The grass carp eats its own weight in lake or pond vegetation every day, and as long as it is kept in still water, it cannot reproduce. There are two problems with grass carp. First, given enough time they will strip a lake or pond bare of all vegetation, which is unhealthy for most lakes or ponds. The second problem is that they are exceedingly smart and difficult to catch or trap.
Chum a section of a pond or lake with corn. Use canned corn or use feed corn than has been soaked in water for three days. If possible, choose an inlet in the lake or pond that will restrict the movements of the fish.
Bait a small hook with a ball of bread dough and cast from a hidden location into the chummed area. Grass carp are easily spooked if they see movement on the shore, so stay well hidden. Be patient. Grass carp are difficult to catch with a hook and line.
Toss a fishing net over the chummed area. Throwing a fishing net requires practice and skill. Hire someone to throw the net for you if you lack the necessary skill. Again, keep hidden as much as possible on the shore before throwing the net.
Drag a dragnet through the water if it is feasible, depending on the size and shape of the lake. Grass carp are difficult to catch in a dragnet unless they are concentrated in a small area from which is it already difficult to escape.
Shoot the fish with arrows. Bow hunting has proven to be an effective method of eradicating grass carp. If you are not proficient with a bow and arrow, then contact a local bow hunting club; members will welcome the challenge.