Use of Echosounder Tracings to Estimate the Aboveground Biomass of Submerged Plants in Lakes

A method is presented to estimate the aboveground biomass of submerged macrophytes in lakes from echosounder tracings and from the growth form of the dominant species in the stand. The equation is[Formula: see text]where species that reach the surface to flower are categorized as form class 1, short understory species with floating flowers as form class 2, and species with underwater flowers, those lacking flowers, and those that, although able to produce flower, never flower in nature as form class 3. The standard error of the estimates is 421 g fresh wt.∙m −2 , a value comparable with the standard error of direct harvest by SCUBA divers. The echosounder-based method is limited to stands growing at depths greater than 70 cm with plants taller than 20 cm.