Initial impact of low stocking density of grass carp on aquatic macrophytes

Grass carp (Ctenopharyngodonidella Val.) stocked at a low density (29 kg ha−1) to one of two small ponds significantly reduced the biomass of aquatic macrophytes (especially of the filamentous alga Cladophoraglobulina Kütz.) and changed the species composition of the higher aquatic plant community. After grass carp stocking (in 1999), Myriophyllumspicatum L., Ceratophyllumdemersum L. and Lemnaceae species replaced the species present originally: Eleocharisacicularis (L.) Roem. et Schult., Potamogetonpusillus L. and P.pectinatus L., which were dominant in 1998.