As the threat of invasive species looms on the Great Lakes, it is comforting to know that great strides to prevent the spread of sea lamprey have been made. Researchers from Michigan State University recently discovered a method in which sea lamprey can be concentrated in order to make the application of lampricides like TFM more effective and less damaging to the environment. Sea lampreys rely heavily on their sense of smell to find breeding grounds; if they smell their young they are attracted to it and if they smell death they are repelled from it. This allows researchers to use a repellant extracted from the carcasses of dead sea lampreys to concentrate sea lampreys into specific locations. These locations can then be treated with lampricides that kill the lampreys with little damage to the environment and surrounding ecosystem. The cost of a round of treatment of lampricides costs around $150,000. By using the repellant, the Great Lakes Fishery Commission, a joint U.S.-Canada commission attempting to eliminate sea lamprey, will be able to control lamprey populations more efficiently while saving money in the process. Marc Gaden, communications director of the Great Lakes Fishery Commission, says, "You're talking about saving in the neighborhood of half a million to a million dollars every four years."
In addition to the use of lampricides, waterway barriers are also being used to prevent further spread of sea lamprey. The Great Lakes Fishery Commission currently uses four different types of water barriers: Electrical, Low-Head, Adjustable-Crest, and Velocity barriers. Electrical barriers use a direct current electrical system embedded in the stream bed in order to deter lamprey during mating season. This type of barrier does not impede the flow of the river which allows desirable species of fish to pass through the barrier. Low-head barriers create a drop in the river large enough to keep lamprey from moving upstream, but small enough to allow jumping species of fish to pass through easily. These are the most common types of barrier being used currently. Adjustable-Crest barriers are very similar to Low-Head barriers, but unlike Low-Head barriers, they are raised only during lamprey spawning seasons. During the rest of the year, it is lowered to riverbed level as to not impede the flow of the river. Velocity barriers take advantage of the lamprey's poor swimming ability. By directing the river's current, high velocity areas of water are created that prevent the lamprey from moving forward but still allows jumping and non-jumping species of fish to pass through freely. Through the use of these barriers, the Great Lakes Fishery Commission is able to keep lamprey from reaching spawning grounds and further concentrate lamprey for the application of lampricides.
The Trail Creek Dam, a lamprey barrier currently in place on Trail Creek near Michigan City, is one such barrier used to control lamprey populations. Trail Creek is one of the largest lamprey producing tributaries in Michigan, producing tens of thousands of lamprey every year. The barrier is located downstream of a large spawning area which prevents lamprey from reaching their spawning beds while still allowing desirable fish through. In addition, the barrier helps concentrate lamprey into one location to be trapped and removed from the river. Not only will the Trail Creek Dam help cut lamprey populations, but also reduce the need for lampricides.
Michigan and the Great Lakes region have made great strides in preventing the expansion of not only sea lamprey but other invasive species. Although many improvements have been made, it may be a long time until the threat of invasive species is no longer present.
Barvinok, Dimitri. "Researchers get help playing ‘Whack-a-mole' with sea lamprey ". Greatlakesecho.org. http://greatlakesecho.org/2012/10/24/repellant-helps-researchers-play-whack-a-mole-with-sea-lamprey/