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Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

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TABLE 21 continued. MANAGEMENT OPTIONS FOR CONTROL OF ALGAEOPTION MODE OF ACTION ADVANTAGES DISADVANTAGESChemical controls14) Management for nutrientinput reduction ♦ Includes wide range ofwatershed <strong>and</strong> lake edgeactivities intended toeliminate nutrient sources orreduce delivery to lake♦ Can involve use of wetl<strong>and</strong>treatment cells or detentionareas created from part oflake♦ Essential component of algalcontrol strategy whereinternal recycling is not thedominant nutrient source, <strong>and</strong>desired even where internalrecycling is important♦♦♦♦♦♦Acts against the originalsource of algal nutritionDecreased effective loading ofnutrients to lakeCreates sustainable limitationon algal growthMay control delivery of otherunwanted pollutants to lakeGenerally most cost effectiveover long termFacilitates ecosystemmanagement approach whichconsiders more than just algalcontrol♦♦♦♦♦May involve considerable lagtime before improvementobservedMay not be sufficient to achievegoals without some form of inlakemanagementReduction of overall systemfertility may impact fisheriesMay cause shift in nutrient ratioswhich favor less desirablespeciesMay cost more in the short term,as source management isgenerally more involved thanone or a few treatments ofsymptoms of eutrophicationBiological Controls15) Enhanced grazing ♦ Manipulation of biologicalcomponents of system toachieve grazing control overalgae♦ Typically involves alteration offish community to promotegrowth of large herbivorouszooplankton, or stocking withphytophagous fish♦♦♦May increase water clarity bychanges in algal biomass orcell size distribution withoutreduction of nutrient levelsCan convert unwantedbiomass into desirable form(fish)Harnesses natural processesto produce desired conditions♦♦♦May involve introduction ofexotic speciesEffects may not be controllableor lastingMay foster shifts in algalcomposition to even lessdesirable forms<strong>Lake</strong> <strong>Pocotopaug</strong> <strong>Restoration</strong> <strong>Evaluation</strong> 118May 2002

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