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|Title:||Recording fathometer techniques for determining distribution and biomass of Hydrilla verticillata Royle|
|Authors:||University of Florida.|
United States. Army. Corps of Engineers. Jacksonville District.
Aquatic Plant Control Research Program (U.S.)
Macéina, Michael J. (Michael John), 1954-
Shireman, J. V.
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: The primary objective of this study was to investigate the possibility of utilizing a recording fathometer to generate quantitative data by conducting transects of submersed vegetation. Data and techniques were evaluated and assessed for accuracy, advantages, and bias. Five quantitative vegetation parameters are presented for determining the abundance of hydrilla: (1.) transect percent cover, (2.) total percent cover, (3.) percent vertical cross-sectional area infestation, (4.) biomass and total standing crop, and (5.) mean hydrilla height and hyrilla-surface distance. Although certain disadvantages and problems were encountered utilizing a recording fathometer for submersed vegetation surveys, valid and accurate quantitative data were generated demonstrating seasonal and/or chemical and biological control fluctuation of hydrilla abundance in Lakes Baldwin and Wales. Conducting vegetation surveys with a recording fathometer proved to be an economical and feasible sampling procedure. Technological advances improving sensitivity and chart tracing output may be possible in the future. Refinement of the techniques presented could also improve the versatility and possibly increase the amount of information that could be obtained from tracings. The results of this study confirm that a recording fathometer can be a useful sampling device to aquatic botanists and researchers evaluating the impact of various control measures on hydrilla. White amur were stocked in Lake Baldwin during 1978. The biomass of all fish was estimated at 121 kg/ha for March 1979, and hydrilla biomass for the same month was estimated at approximately 0.6 million kilograms.
|Appears in Collections:||Miscellaneous Paper|