Aquatic Weed Control in Ponds - Aquaculture at Kentucky State ...

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Robert M. Durborow, Ph.D., ProfessorState Extension Specialist for AquacultureAquaculture Center, Kentucky State UniversityFrankfort, Kentucky 40601Telephone: (502) 597-6581Fax: (502) 597-8118Email: robert.durborow@kysu.eduCraig S. Tucker, Ph.D., ProfessorDirector of Southern Regional Aquaculture CenterDelta Research and Extension CenterMississippi State UniversityStoneville, Mississippi 36842Boris I. Gomelsky, Ph.D., Associate ProfessorAquaculture CenterKentucky State UniversityFrankfort, KY 40601Richard J. Onders, Research Co-investigatorAquaculture CenterKentucky State UniversityFrankfort, KY 40601Steven D. Mims, Ph.D., ProfessorAquaculture CenterKentucky State UniversityFrankfort, KY 406012
Aquatic Weed Control in PondsBob Durborow, Craig Tucker, BorisGomelsky, Rick Onders and Steve MimsPonds are ideal habitats foraquatic plants, and some will always bepresent. Plants are a necessarycomponent of pond ecosystems becausethey perform valuable functions.Photosynthesizing plants produceoxygen that is needed to sustain fish life.Also, plants assimilate ammonia that isexcreted by fish thereby helping toprevent accumulation of potentially toxicconcentrations of ammonia.Nevertheless, plants can cause problemsin ponds and control measures oftenmust be used to eliminate or reduce theirabundance.Types of weedsThe plants that grow in pondscan be categorized into two groups. Thealgae are primitive plants that have notrue roots, stems, or leaves, and do notproduce flowers or seeds. Algae can becategorized as phytoplankton orfilamentous algae.The higher aquatic plants aremore advanced, and usually have roots,stems, and leaves, and produce flowersand seeds. Higher aquatic plants caneither be submersed, emergent, orfloating.AlgaePhytoplankton. These algae aremicroscopic simple plants suspended inwater or forming floating scums of nearmicroscopiccolonies on pond surfaces.Communities of phytoplankton arecalled the “bloom.” There are hundredsof species of phytoplankton, andidentification of the different species isdifficult, requiring a microscope.Phytoplankton are the mostcommon type of plant found in ponds.Moderate densities of phytoplankton aredesirable in ponds because they shadethe pond bottom preventingestablishment of more troublesome typesof plants. Phytoplankton become a weedproblem when they become excessivelyabundant or when certain undesirablespecies become dominant in thecommunity. Excessive phytoplanktonabundance causes serious water qualityproblems such as frequent periods ofdangerously low concentrations ofdissolved oxygen. This problem is oftenassociated with dense blooms of bluegreenalgae (Figures 1 & 2). The bluegreenbloom floats to the top of the pondforming a scum that can block sunlightand prevent proper photosynthesis.These blooms can also cause an offflavorproblem in fish raised inaquaculture ponds.Figure 1. Blue-green algae(cyanobacteria) forming a surface scum.Figure 2. Blue-green algae floating on apond surface.3
Page 1: Aquatic Weed Control in PondsRobert
Page 5 and 6: Figure 6. The filamentous algae,Pit
Page 7 and 8: Polygonum spp. (smartweed) - leaves
Page 9 and 10: Prevention of aquatic weedsAlmost a
Page 11 and 12: Water draw-downs. Periodicwater dra
Page 13 and 14: y the Environmental Protection Agen
Page 15 and 16: days after application up to 4.25 p
Page 17 and 18: pond surface at once. (Partial or s
Page 19: to a non-toxic level and these nutr
Page 22 and 23: Aquatic group &vegetationCopper sul
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Aquatic Weed Control in Ponds - Aquaculture at Kentucky State ...

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