We have been involved in managing established aquatic invasive species populations in the Adirondack Park since 1999, with the initiation of Eurasian watermilfoil control activities in Upper Saranac Lake. In 2004 we began an unprecedented intensive whole-lake milfoil control effort in Upper Saranac Lake using diver hand-harvesting that was highly successful. This effort was carefully monitored using permanent underwater transects and we shared the results in numerous formats to demonstrate that diver hand-harvesting can be a viable method for controlling Eurasian watermilfoil even at large scales. The Upper Saranac Lake findings provided scientific justification for wider use of hand-harvesting and also helped start up Aquatic Invasive Management (AIM), a highly successful private business working to control AIS in the Adirondacks and beyond.

The management team uses hand-harvesting to remove aquatic plants, typically with a four person crew consisting of three divers supplied with breathing air by a floating hookah rig and a top water support person. The divers remove the entire aboveground portion of the plants and as much root material as possible and then place the plants in mesh bags that are handed off to a top water support person when full. The top water support person also collects plant fragments floating on the surface and warns boaters away from the dive area. Harvested materials are disposed of at designated sites approved by local and state authorities. The team also maintains a daily log of activities, which includes mapping work areas with GPS and reporting plant removals. This data is transferred into ArcGIS to produce operational surveys and accounting of removals for tracking and reporting progress.

We also assist lake groups with developing management plans and permits, and conduct lake surveys to collect AIS and native plant data for planning, permitting, and reporting purposes. Please contact us if your organization is interested in such services.

Management Program
Milfoil Control in Upper Saranac Lake

An intensive hand harvesting project was undertaken to achieve whole lake control of Eurasian watermilfoil (hereafter called milfoil) in Upper Saranac Lake, New York. Milfoil cover and removal data was collected and the process was monitored using underwater transects to track milfoil response to management. Milfoil cover was reduced to rare for over 90% of the littoral area and plant removal decreased from 18.32 Mg (20.19 US tons) in 2004 to 0.21 Mg (0.23 US tons) in 2006, the final year of intensive management. Milfoil density at monitoring sites dropped from 1,380 stems/ha in 2004 to 73 stems/ha in 2006, with similarly low density during the maintenance period. Control cost averaged $1,003 ha/yr during intensive management and $351 ha/yr during the maintenance period. Results indicate that hand harvesting can be used to achieve whole-lake control; however, successful use of this technique requires a large financial investment and a commitment to control in perpetuity.

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The mission of the Adirondack Watershed Institute of Paul Smith's College is to protect clean water, conserve habitat, and support the health and well-being of people in the Adirondacks through science, collaboration, and real world experiences for students.

Adirondack Watershed Institute
Paul Smith's College
P.O. Box 265, Paul Smiths, NY 12970-0244
Tel: 518-327-6213
Fax: 518-327-6369