PRODUCTION OF Eichhornia crassipes 463 ON TWO METHODS TO ESTIMATE PRODUCTION OF Eichhornia crassipes IN THE EUTROPHIC PAMPULHA RESERVOIR (MG, BRAZIL)

(With 2 figures) This paper deals with variations in biomass and in the production of Eichhornia crassipes (water hyacinth) in a eutrophic tropical reservoir. Net production was assessed by both a traditional method and a demo-graphic approach. The initial biomass ranges from 96 g DW.m–2 to a maximum of 2027 g DW.m–2. Net production estimates varied greatly according to which method was used to calculate them (tra-ditional: 20.6 ton DW.hectare–1.year–1, demographic: 226.9 ton DW.year–1)