ABSTRACT
It becomes increasingly important that biological methods be used for controlling undesirable aquatic plants in artificial impoundments and natural waters since many of our existing chemical control methods are potentially hazardous to the ecological balance of ponds, lakes, rivers, and to man himself. A number of organisms exist that can effectively control or eliminate certain aquatic plants. Several fish species have shown promise as weed control agents. One of these is the white amur, Ctenopharyngodon idella Valenciennes, also known as grass carp. 1 This fish has been in the U.S. for a decade, but it is an exotic species, indigenous to large rivers in China. One major reason that white amur are not widely used in this country is the fear that they may become established in our natural waters, as did the common carp, and compete for food organisms with native fish. Hora and Pillay 2 reported that white amur do not spawn in ponds but in large rivers. If this is so, and it seems to be, they can possibly be used in ponds not connected to natural waters.
