Sea Lamprey Experts
Lake Champlain Sea Lamprey Control
A panel of professionals involved in sea lamprey control in Lake Champlain assembled at the 2006 Northeast Fish & Wildlife Conference in Burlington, Vermont to discuss current issues involved with Lake Champlain sea lamprey control.
The panel participants were:
- Brian Chipman, District Fisheries Biologist, Vermont Fish and Wildlife Department;
- Dr. Ellen Marsden, Associate Professor, Rubenstein School of Environment and Natural Resources, University of Vermont;
- Bradley Young, Fishery Biologist, U.S. Fish and Wildlife Service; and
- Douglas Stang, Bureau of Fisheries Chief, New York State Department of Environmental Conservation;
- Dave Tilton, U.S. Fish and Wildlife Service Lake Champlain Project Leader, served as moderator of the discussion.
History of Salmon, Lake Trout and General - Brian Chipman
Vermont Fish & Wildlife Department Fisheries Biologist Brian Chipman began the discussion with a brief history of the Lake Champlain fishery, sea lamprey and the control program.
Mr. Chipman pointed out that when explorers and settlers first came to Lake Champlain they reported salmon runs in the tributaries that were so abundant that "salmon were harvested by the wagon load with pitchforks." Lake trout were also reported to be very abundant. By the mid 1800s overfishing, pollution and damming of tributaries had exterminated salmon, and lake trout disappeared from the lake by 1900. In the late 1950s and 1960s New York State began stocking lake trout and salmon with some limited success.
In 1973 the Lake Champlain Fish and Wildlife Management Cooperative (the Cooperative) was formed between the U.S. Fish and Wildlife Service, the New York Department of Environmental Conservation and the Vermont Fish and Wildlife Department to protect and manage the fish and wildlife resources in Lake Champlain. The Cooperative established a lake-wide salmonid restoration program which included coordinated annual stocking of salmon and lake trout.
While anglers were catching lake trout and salmon, sea lamprey and sea lamprey wounds were found on many of the fish. Studies conducted by the Cooperative concluded that low salmon and lake trout survival from sea lamprey parasitism was preventing the Cooperative from attaining the goals of restoration through stocking alone - the sea lamprey population needed to be brought into control.
In 1990 an eight-year experimental program to control sea lamprey in Lake Champlain began. The program resulted in a significant decrease in lamprey wounding rates, improved survival of salmon and lake trout, and dramatic improvements in the lake's fishery. In 2002 the current extensive, integrated, long-term program was implemented by the Cooperative. The program is designed to enhance sport fish populations and restore ecosystem function through: applications of chemical lampricides that control larval sea lamprey populations; establishing barriers to upstream migrating adults; and trapping adult spawning-phase sea lamprey.
Long-term sea lamprey control had begun to reduce wounding rates by 2004, however wounding rates rebounded in 2005. The reason for this, reported Mr. Chipman, is that control efforts had not yet occurred in five major sea lamprey-producing waters. The largest producers are the Pike River system in Quebec and the Poultney River, on the border of Vermont and New York. The Lamoille, LaPlatte and Missisquoi Rivers in Vermont are also producing sea lamprey.
"The Poultney River was last treated in 1996, while the other four rivers were not previously targeted for sea lamprey control. Efforts must now be undertaken in these waters to ensure the success of the sea lamprey control program," Mr. Chipman stated.
Native or Non-native Invasive - Dr. Ellen Mardsen
University of Vermont Associate Professor Ellen Marsden presented information on recent research that suggests sea lamprey may be native to Lake Champlain and discussed why sea lamprey populations are exhibiting characteristics of an invasive species and disrupting the lake's ecosystem.
At the start of her presentation, Dr. Marsden stated, "Whether the sea lamprey is native or non-native, it is having a significant detrimental effect on Lake Champlain's fishery and their populations must be controlled in order to obtain a balanced lake ecosystem."
Dr. Marsden discussed genetic research that seems to support the position that sea lamprey are native to Lake Champlain. Under this scenario, salmon and trout would have shared Lake Champlain with the sea lamprey for thousands of years and therefore would have evolved means to be less susceptible to sea lamprey parasitism. This could account for the lack of reports of sea lamprey or lamprey wounds on fish prior to mid 1900s. Unfortunately, the Lake Champlain strains of salmon and lake trout are lost forever.
If in fact the sea lamprey are native to Lake Champlain, the modern abundance of the sea lamprey, and the significant detrimental impact on Lake Champlain's fishery and ecosystem, may then be explained by two factors. The change in human use of the lands and waters in the lake's watershed may have resulted in increased habitat for larval lamprey. Also the strain of Atlantic salmon that has been stocked in Lake Champlain did not evolve with lamprey and therefore may be more susceptible to sea lamprey parasitism - though the strain of lake trout currently being stocked appears to have greater resistance to sea lamprey than do other strains.
Despite two decades of stocking the most lamprey-resistant lake trout strain, sea lamprey populations remain out of balance with the Lake Champlain ecosystem. Balance can not be achieved at this time without substantial efforts to control sea lamprey populations.
Integrated Control Methods - Bradley Young
U.S. Fish & Wildlife Service Fisheries Biologist Bradley Young spoke on innovative techniques that are being practiced and explored in an effort to enhance integrated pest management of Lake Champlain's sea lampreys and to reduce the reliance on pesticides.
Currently the most commonly used method of sea lamprey control is lampricides that kill the larval form of the sea lamprey. The lampricides are TFM, which is used to treat the tributaries of Lake Champlain, and Bayluscide, which is used to treat the deltas.
Mr. Young began his portion of the panel discussion by pointing out that the agencies that are working to control sea lamprey populations don't use chemicals in the waters of the Lake Champlain watershed because they "like to". Rather the lampricides are used because they are the most effective tool available for controlling sea lamprey populations.
Further, there is a well documented history of using TFM in the Great Lakes and other waters, and it has clearly proven to be one of the safest, most target specific pesticides in use today. Having said that, Mr. Young went on to explain that the members of the Cooperative utilize, and continue to review, other means to effectively control sea lamprey populations and reduce the amount of pesticide expended.
One of the methods being studied is the use of the chemical niclosamide (the active ingredient in Bayluscide) in combination with TFM. The combination of the two lampricides has a multiplier that would allow the use of less lampricide, without being any less effective. If found to be feasible, this practice will not only reduce the amount of lampricide placed into the waters of the Lake Champlain watershed, but it will also reduce the costs for purchasing the lampricide - the largest treatment expense incurred.
Barrier dams have been built or repaired on some tributaries to prevent adult sea lamprey from reaching spawning areas. Typically these are permanent structures that are designed to prevent sea lamprey from moving upstream while allowing other fish to pass. The Cooperative is researching temporary barriers similar to those used for Atlantic salmon studies in Maine. These barriers are set up after ice out in the spring and then are taken down after the sea lamprey spawning period ends in early summer. The barriers are essentially a system of grates that allow water and smaller fish to pass through but not adult sea lamprey.
The barrier can be used in combination with a trap, so that any larger fish attempting to get upstream can be removed from the trap and placed back in the water on the upstream side, while sea lamprey would be removed and destroyed. The Cooperative and Quebec officials are discussing the possible use of the temporary barriers on Morpion Stream, which has been found to produce a significant number of sea lamprey.
Traps are used on a number of streams to capture adult sea lamprey when they migrate up tributaries to spawn. However, not all tributaries are suitable for the setting and operation of these traps. The Cooperative is looking at possible ways to draw the adult sea lamprey into the smaller side tributaries that are suitable for trapping through the use of pheromones. Pheromones are chemical attractants naturally produced by breeding adults and larval sea lamprey. The release of pheromones into small streams, at points upstream of traps, is showing promising results for drawing adult sea lamprey out of the main tributaries and into the traps.
Though it is a very fresh idea, Mr. Young also discussed the possibility of using the sea lamprey's own genes against itself. Scientists are currently working to map the sea lamprey genome. Once this is accomplished, researchers can look for certain genes that could be triggered that would cause a disruption in the sea lamprey's breeding or life cycle.
"Each sea lamprey-producing tributary to Lake Champlain possesses a unique compliment of physical, biological, chemical, social, and political attributes," Mr. Young stated. "As we develop new and improved techniques for controlling sea lamprey, we can better prescribe and integrate control techniques to match the specific needs of each stream. These emerging technologies enable us to maximize the effectiveness of our control program while reducing both the impacts on the non-target environment and the financial cost of control."
Priority of Sea Lamprey Control - Douglas Stang
New York State Department of Environmental Conservation (NYSDEC) Bureau of Fisheries Chief Douglas Stang explained the priority NYSDEC gives to sea lamprey control. Mr. Stang outlined the factors for determining an organization's priorities which included funding, staff time and what other work is forgone because effort is going into a priority project.
Mr. Stang first pointed out that the most recent statewide angler survey found that Lake Champlain ranks 12th or 13th statewide in the amount of angler effort and money spent by anglers when fishing a water. However, if one looks at NYSDEC's Region 5 - an eight county administrative region that is approximately the same size as the State of Vermont - Lake Champlain ranks second in both angler effort and money spent by anglers. Obviously, Lake Champlain is a very important fishery in NYSDEC Region 5.
Likewise, while overall NYSDEC fisheries staff time spent on Lake Champlain sea lamprey control is small, in 2004/05 almost 40% of NYSDEC Region 5 fisheries staff time was dedicated to this effort. When looking at just recreational fish management efforts (this excludes stream protection, permitting and other non-management tasks) nearly 70% of NYSDEC Region 5 fisheries staff time was dedicated to Lake Champlain sea lamprey control. Clearly sea lamprey control is a high priority for NYSDEC Region 5.
Mr. Stang further went on to point out that if Region 5 fisheries staff weren't putting all this time and effort into sea lamprey control, there were plenty other fishery management efforts to which they could direct their attention, such as: Adirondack brook trout restoration, walleye management, public fishing rights, routine fishery monitoring & assessment, and Adirondack Forest Preserve unit management planning.
"Lake Champlain sea lamprey control has been and remains a high priority among the government fishery management agencies because restoring the Lake Champlain fishery and providing the associated benefits to anglers and communities will be the end result," Mr. Stang stated. "We have not yet fully realized the potential for the sport fishery and fish population restoration that can be achieved, because we have not yet conducted a complete sea lamprey control treatment of the lake and its tributaries."
The panel was assembled to address the following questions:
- What is the history and current status of sea lamprey control in Lake Champlain?
- Are sea lamprey native to Lake Champlain or non-native invasives?
- What techniques can be utilized to enhance integrated pest management of Lake Champlain's sea lampreys?
- What priority is given to Lake Champlain sea lamprey control by the government fishery management agencies?
The short answers to these questions are:
- Gains had been made in controlling sea lamprey and their impacts, however, some of the gains have been lost due to new waters producing sea lamprey - control efforts must be made on these waters to obtain the desired level of wounding rates.
- Regardless of whether sea lamprey are native to Lake Champlain or not, currently sea lamprey exhibit the behavior of an invasive fish species. Sea lampreys are having a detrimental impact on the lake's ecosystem and therefore control efforts must continue to bring balance to the system.
- Efforts will continue to be made to research and utilize various control techniques so as to effectively control sea lamprey and minimize the use of pesticides. At this time the use of lampricides, combined with barriers and traps, is the most effective means for controlling sea lamprey in Lake Champlain.
- Sea lamprey control is a high priority of government fishery management agencies, because through this control a world class trout and salmon fishery may be restored.