Environment DEC
From the October 2004 issue
State Continues Lake Champlain Sea Lamprey Control Program
During September, sea lamprey control treatments were conducted in two tributaries and one delta of Lake Champlain in continuation of a long-term effort to protect the lake's fishery from this non-native, parasitic fish. Trout and salmon populations, native to Lake Champlain, benefit from this action, as do anglers.
Two sea lampreys killed
this trout by attaching
their mouths to its sides
and eating its flesh
"DEC performs sea lamprey treatments annually to protect our trout and salmon fisheries in Lake Champlain, which are an important part of the lake's ecosystem." DEC Commissioner Erin Crotty said. "The Lake Champlain fisheries also are important to the local economy. DEC will continue to work with its counterparts at the federal level and in Vermont to ensure the long-term protection of Lake Champlain and its local fishing industry."
The sea lamprey uses
its rasp-like mouth (seen here),
to bore a hole into the side
of a fish and feed on its tissues
(Photo courtesy USFWS)
Treatment Areas and Methods
This year's treatments began in early September and were expected to be completed by early October. Staff from DEC, the Vermont Department of Fish and Wildlife, and the U.S. Fish and Wildlife Service administered the treatments, targeting the larval stage of sea lamprey. A third tributary in Vermont, the Winooski River, also was treated.
In the Lake Champlain system, most immature sea lamprey live in streams for four years before descending into Lake Champlain to prey on fish like trout and salmon. Under the Sea Lamprey Control Program, a pesticide, TFM (trifluoromethyl-nitrophenol), is applied in precise concentrations to streams in a continuous, metered manner over a period of approximately 12 hours in order to kill the immature, larval form of the sea lamprey.
Sometimes larval sea lamprey also inhabit the lake bottom near the mouths of rivers. In these areas, where TFM is not effective, another pesticide (bayluscide-niclosamide) is applied using boats equipped with agricultural spreaders. The granular compound sinks to the lake bottom where it dissolves to treat larval sea lamprey.
Informing and Assisting the Public
DEC set up a toll free number for the public to obtain information on sea lamprey treatments. Callers could request information about the treatment schedule for specific waters, progress reports, updates on treatments and water use advisories.
Following each treatment, temporary water use advisories were in effect in specific areas to minimize human exposure to the treatment compounds. The State Department of Health recommended that treated river and lake water not be used for drinking, swimming, fishing, irrigation, or livestock watering for the brief period when lamprey control chemicals were present. In addition, people were informed that fish within the area treated with bayluscide may have contained low-level concentrations of the compound for 14 days following treatment.
Treating waterbodies is critical
to controlling this parasite
The treatments and water use advisories had no effect on most residents in the Champlain basin, and no municipal water supply systems were affected. DEC staff identified all riparian landowners along the waters for which treatments were planned. Last spring, these residents received letters informing them of the planned treatment and asking them whether they or their livestock used water from a surface supply that would be affected by the treatment. Days before the treatment began, residents received another letter informing them that the treatment was forthcoming.
DEC staff also contacted residents who had indicated that they used the river or lake in an advisory area as a water supply, and those residents were advised of the treatment. In addition, DEC provided a supply of water to impacted residents who requested it for themselves and their livestock.
Local television and radio stations broadcast the dates when advisories were to begin and end. However, the treatment schedule was subject to change because of weather conditions, stream flows or technical problems that could have arisen in the meantime. If that happened, residents were notified of the changes beforehand.
Treatment Results
DEC studies have shown that sea lamprey control results in decreased wounding and scarring rates to other fish and can increase populations of lake trout and landlocked salmon. DEC's surveys of anglers showed that they caught more and substantially bigger trout and salmon as a result of the previous treatment program.
Sea lamprey control also generates a favorable economic benefit/cost ratio as angling opportunities increase. According to a benefit cost analysis of the eight-year experimental Sea Lamprey Control Program on Lake Champlain-a study conducted by Alphonse H. Gilbert, a researcher from the University of Vermont-sea lamprey control generated benefits of approximately $29.4 million, with costs of about $8.4 million. These benefits were due to the increased number of boaters and anglers spending longer periods of time in the Lake Champlain area.
