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Trtclopyr for selective whole -bay mitfoll management there has also been concern that these low rate treatments may be selecting for hybrid watermilfoil (M. spicatum x M sibiricwn), and there is value in determining the ratio between EWM and hybrid watermilfoil in managed and un- managed bays. , The incorporation of biomass and hydroacoustic data into this project provided a more thorough assessment of the status of EWM and native plant responses to the treatment. Incorporating several monitoring techniques to assess treat- ment results can provide improved context on treatment out- comes to interested stakeholders and regulators. During this evaluation effort, there has been rapid change in the use of hydroacoustic technology to provide SAV maps of entire bays and lakes This technology will continue to move for- ward, and although we did not include mapping in our orig- inal project objectives, by the end of this project we were collecting data via navigation of the point -intercept grids that allowed rapid and relatively passive whole -bay map- ping of SAV in each bay. Although this technology is still being vetted and the strengths and weaknesses discussed (Valley et al. 2015, Radomskt and Holbrook 2015), there is significant promise for resource managers to incorpo- rate this technology to generate large-scale, low-cost maps of SAV distribution and abundance through time. Both of these assessment techniques suggest that low rate triclopyr applications can provide good initial control of EWM while minimizing any sustained impacts to the native plant com- munity. One key observation from the hydroacoustic units related to the abundance of coontail in the deep water sites in these bays. Although we were able to detect strong signatures of vegetation growing 1-2.5 m in height in water depths of 5-7 m, these extensive plant beds were almost exclusively dense monocultures of coontail, as confirmed by multiple rake tosses. This finding was not included in the frequency data; however, any future large-scale management plans need to include these large coontail beds. As a non -seated macrophyte, coontail is capable of sequestering nutrients from the water column and thus converting them into plant biomass, providing habitat and sediment stabilization in the deeper waters of these bays Moreover, these results sug- gest that plant surveys should account for maximum depth of plant colonization versus use of an arbitrary depth for sampling. . Although there has been discussion of the potential merits of early -season herbicide applications in the upper Midwest for improved selectivity (Poovey et al. 2002, Skogerboe et a1. 2012), results from this trial suggest some caution should be exercised when using large-scale triclopyr. Re- cent mesocosm work demonstrated that under some scenar- ios, early -season treatments were much less effective than later -season applications (Netherland and Glomski 2014). In contrast, the native plants included in this mesocosm trial were not impacted by treatment timing with tnclopyr. Early -season strategies may also be compromised by lack of a thermochne and potential rapid loss of herbicide to deeper water The integration of frequency, biomass, hydroacoustic data, and herbicide concentration data represented a significant investment of time in assessing a treatment outcome. Al- though such an extensive approach is not a good fit for ev- ery monitoring project, it does yield several complimentary pieces of information that can provide resource managers with a more complete picture of treatment outcomes. This approach is likely a good fit for large-scale, high-profile projects where stakeholders have disparate objectives. The ability to display distinct areas occupied by invasive plants and quantify their density can provide data in place of anec- dotal observations. Acknowledgments The authors than Mr. John Skogerboe for sampling assis- tance and Mr. Gabriel Jabbour, the proprietor of Tonka Bay Marina, for providing excellent logistical support through- out hroughout this project. Numerous discussions between the authors and Chip Welling of the Minnesota Dept of Natural Re- sources (MN DNR) were beneficial in adapting sampling strategies to capture useful information. Funding This study was funded by the MN DNR via a Coopera- tive ooperstive Research and Development Agreement with the US Army Engineer Research and Development Center. Permis- sion was granted by the Chief of Engineers to publish this work. References Crowell WJ, Pmulx NA, Welling CH. 2006. Effects of repeated fluddone treattnents over nine years to control Eurasian wa- terni foil in a mesotrophic lake. J Aquat Plant Manage. 44.133-136. Fox AM, Haller WT, Getsinger KD, Petty, DG. 2002. Dissi- pation of triclopyr herbictde applied in Lake Minnetonka, MN concurrently with rhodatnme WT dye Pest Manage Sci. 58:677-686. Getsinger KD, Madsen JD, Koschmck TJ, Netherland MD, 2002. Whole -lake fluridone treatments for selective control of Eurasian watermilfoil: I Application strategy and herbicide residues. Lake Resery Manage. 18181-190 GetsingerKD, Petty DG, Madsen JD, Skogeiboe JG, Houtman BA, Haller WT, Fox AM. 2000. Aquatic dissipation of the herbi- cide t6clopyr in Lake Minnetonka, Mummta. Pest Manage. Sci. 56 388400 321