Sea Lamprey
Management
Past, Present and Future
How we came to be
Sea lampreys, a parasitic fish native to the North Atlantic Ocean and many of its tributaries, invaded the lower Great Lakes in the late 1800's and early 1900's and eventually reached the upper Great Lakes in the mid to late 1930's. Niagara Falls had served as a natural barrier until the construction of the Welland Canal in 1829 for the shipping industry.
Sea lampreys attach to fish with a sucking disk and sharp teeth and then feed on body fluids resulting in scars or death to the host fish. The invasion of sea lampreys combined with over harvest by commercial fisheries lead to a collapse of the lake trout fishery by the mid to late 1950's in most of the Great Lakes. As the lake trout population diminished, sea lamprey attacks on other species of fish increased and ultimately lead to great changes in the aquatic biota of the Great Lakes.
Studies of the sea lamprey's life cycle by biologists from the State of Michigan and U.S. Fish and Wildlife Service determined that the most vulnerable period of a sea lamprey's life occurs in the stream. In 1950, the U.S. Fish and Wildlife Service established the Hammond Bay Biological Station to develop control measures. The Hammond Bay Biological Station is now part of the U.S. Geological Survey (USGS).
Early efforts at sea lamprey control were concentrated on prevention of spawning by adult sea lampreys. Mechanical and electrical weirs were constructed to block adult sea lampreys from ascending streams and rivers in spring and early summer. Operation of weirs was hampered by floods, logs and other floating debris, or loss of electrical power. Interruptions in weir operations allowed spawning sea lampreys to ascend rivers thus completing their life cycle.
The next effort to control sea lampreys was at the larval or ammocete stage, when they are burrowed for three or more years in a stream's sand and silt bottom. By the late 1950's, researchers at the Hammond Bay Biological Station had discovered a selective toxicant, TFM, from a field of more than 6000 tested chemicals, which could be applied to streams to kill larval sea lampreys. Since Lake Superior still had some stocks of lake trout and a lower abundance of sea lampreys, it's tributaries were targeted for the first lampricide treatments in 1958. Treatments were extended to Lake Michigan and Huron streams in 1960, Lake Ontario in 1972 and Lake Erie in 1986. TFM has remained the main method of control for about 40 years. Lampricide treatment schedules are developed using factors such as abundance of sea lamprey ammocetes, number of potential sea lamprey transformers, and presence of special concern species.
Where we are going The future of sea lamprey management in the Great Lakes is rapidly progressing because of new technology. Since the late 1970's, efforts have been made to develop an integrated pest management approach with the addition of management tools such as low-head barriers, new styles of electrical weirs and sterilization of male sea lampreys for release. The Great Lakes Fishery Commission has stated a goal of reducing dependance on chemical control (TFM) by 20% by the year 2010.
Since the control program began in 1958, laboratory and field studies have been conducted to determine the effect of an application of lampricide in streams (treatment) on nontarget organisms (all aquatic organisms except the sea lamprey). Larval sea lampreys are significantly less tolerant to lampricide exposure than most nontarget organisms. Most larval sea lampreys are eliminated during treatments and most nontarget organisms survive. Since 1981, additional studies have been conducted to determine methods to further minimize the risk to nontarget organisms (fishes, invertebrates, and amphibians). Since 1996, the lake sturgeon, Acipenser fulvescens, and the mudpuppy, Necturus maculosus, have been the focus of laboratory and field projects. Research was conducted by the Upper Midwest Environmental Sciences Center of the USGS. Treatments are managed to protect and avoid disturbance of federal and state-listed endanged, threatened, candidate, and special concern species and other species of special interest to state, provinical, and tribal jurisdictional agencies.
Laboratory and field studies of the Sterile Male Release Technique in sea lamprey management began in 1971, and experimental implementation of the technique began in 1991. Adult male sea lampreys are trapped, sterilized, and released into several Lake Superior streams and the St. Marys River. Eggs are extracted from sea lamprey nests and analyzed to determine effectiveness of the program.
Low-head barriers have been constructed on some U.S. and Canadian streams which are difficult to treat. These barriers combined with traps block spawning runs of adult sea lampreys, while allowing for passage of jumping fish such as rainbow trout. Larger and more efficient trapping facilities are concurrently being developed for use at low-head barriers or existing power dams in order to provide more male sea lampreys for sterilization and the removal of female sea lampreys.
Since the adult sea lamprey population in northern Lake Huron remains at high levels, studies were conducted on the St. Marys River bordering the U.S. and Canada with the use of deep-water electrofishing gear, GIS (Geographic Information System) and GPS (Global Positioning System). These new technologies have allowed us to better understand larval sea lamprey distribution and abundance in the St. Marys River and ultimately to better coordinate control efforts in this large and very complex river system.
The use of portable computers during field operations has resulted in more efficient analyses of data gathered by treatment personnel prior to a treatment. Improved methodologies and technologies during control operations have reduced the use of TFM by over 25% since 1990.
