Cost and effectiveness of hand harvesting to control the Eurasian watermilfoil population in Upper Saranac Lake, New York

Journal of Aquatic Plant Management, 48:1-5

Daniel Kelting & Corey Laxson

An intensive hand harvesting project was undertaken to achieve whole-lake control of Eurasian watermilfoil in Upper Saranac Lake, New York. Beginning in 2004, six crews of divers hand harvested the entire littoral zone of Upper Sa- ranac Lake twice per summer for three years, after which the harvesting effort was scaled down to a maintenance configu- ration. Eurasian watermilfoil cover and removal data were collected by the crews, and the process was also monitored using permanent underwater transects to track the Eurasian watermilfoil response to management. Eurasian watermilfoil cover was reduced to rare (<5% cover) for more than 90% of the littoral area, and plant removal decreased from about 16,640 kg in 2004 to 460 kg in 2006, the final year of inten- sive management. Eurasian watermilfoil density in the transects dropped from 1650 stems/ha (±343 S.E.) in August 2004 to 63 stems/ha (±9.26 S.E.) in August 2006, with simi- larly low density during the maintenance period. Labor cost averaged $351,748/yr during intensive management and $146,475/yr during the maintenance period. Results indi- cate that hand harvesting is a viable management technique for achieving whole-lake control of Eurasian watermilfoil; however, successful use of hand harvesting requires a large fi- nancial investment.