MANAGEMENT OF AQUATIC PLANTS IN MULTI-USE LAKES WITH GRASS CARP (CTENOPHARYNGODONIDELLA)

Abstract

ABSTRACT Recent hatchery advances producing sterile triploid grass carp and the relaxing of state and federal restrictions on their distribution are expected to result in widespread use of these fish for aquatic plant management in North America. This large Asian cyprinid is a voracious herbivore and must be used properly to avoid major reductions in desirable aquatic vegetation. Grass carp exhibit strong food preferences and should only be used to manage plants that they prefer. Their use to manage plants that they do not prefer can result in expansion of the target plant and severe reductions in non-target species. Food preferences must be verified regionally. For best results, plant biomass should first be reduced and then grass carp should be stocked at 2 fish per metric ton of remaining vegetation. Grass carp should not be used to control aquatic plants in waterfowl management areas. Because grass carp are very difficult to recapture, overstocking should be avoided. Overstocking grass carp has result...