Photo by T. Lawrence, GLFC
Although this creature may look like something dreamt up for use in a horror movie, these fish are very real and have their own sort of horror story in the Great Lakes. The Sea Lamprey (Petromyzon marinus) is a jawless fish that resembles an eel in appearance. Able to live in both marine and freshwater habitats, the sea lamprey’s home range includes the Mediterranean Sea, the Atlantic coasts of Europe and the United States, and freshwater habitats in Europe and the US (USGS NAS 2016). This fish gained notoriety when it expanded its range into the Great Lakes ecosystem, causing devastation.
How did the sea lamprey get into the Great Lakes?
Researchers are unsure as to whether the sea lamprey is native to Lake Ontario, or whether it was introduced after the completion of the Erie Canal (USGS NAS 2016). However, the lamprey is not native to the rest of the Great Lakes, where it is now found today. When the Welland Canal was completed in 1829, linking Lake Ontario with Lake Erie, it provided a corridor through which the sea lamprey was able to invade, but it took over a century for the first sea lamprey to be found in Lake Erie. This happened in 1921 (Trautman 1981). However, within thirty years, the fish had established populations in the remaining three Great Lakes: Lake Michigan, Lake Huron, and Lake Superior (USGS NAS 2016). The sea lamprey had successfully invaded the largest freshwater lake system on Earth.
What impact did the sea lamprey’s introduction have on the Great Lakes?
The sea lamprey is a parasite, meaning that it lives on another organism (its host) to get its nutrients, to the detriment of the host. The sea lamprey uses its teeth to attach to a fish, grind through their scales and skin, and feed on the fish’s blood and other bodily fluids. The following is an image of sea lampreys attached to a trout.
Photo by US Fish and Wildlife
This parasitism can result in the death of the host fish, either due to loss of blood or due to infection (NY Department of Environmental Conservation). One sea lamprey is able to kill as much as forty pounds of fish in one year (National Ocean Service 2016). Sea lampreys prey on large sporting fish, including trout, pike, salmon, walleye, and sturgeon which are commercially fished in the Great Lakes (NY Department of Environmental Conservation). In 1940, as the sea lampreys were in the process of becoming established in the Great Lakes, these fisheries were valued at $5.5 million dollars. After the sea lamprey was introduced, these fisheries collapsed. From 1938-1959, the lake trout fishery in Lake Huron went from producing 2268 tons of fish to a complete crash. In Lake Michigan, lake trout catches went from 2948 tons to 1181kg in ten years (Smith and Tibbles 1980). Not only did the sea lamprey invasion have severe impacts on the fish already living in the lakes, it had a negative financial impact as well.
What can be done to control sea lamprey populations?
When trying to combat the sea lamprey, wildlife managers tried using barriers to prevent the sea lampreys from breeding in streams. Physical barriers such as dams were designed prevent lampreys from passing through, while still allowing other “good” fish to pass. Electrical barriers were put in place to prevent lampreys from entering rivers to lay their eggs. While these barriers were somewhat effective and are still in place today, they were not able eliminate the problem of the sea lamprey (Great Lakes Fishery Commission 2000; Smith and Tibbles 1980). In 1958, managers started using a chemical called 3-trifluromethyl-4-nitrophenol, commonly abbreviated as TFM, to control lamprey populations. TFM is a lampricide, a chemical designed to kill lamprey in their breeding streams when they are still young. This prevents them from growing up and doing damage to fish populations. The lampricide proved to be effective, greatly reducing population sizes of the sea lamprey (Smith and Tibbles 1980). This has allowed some fish populations decimated by the lamprey to increase, but it will take more time for the fisheries to fully recover (USGS NAS 2016). However, treatments with TFM are ongoing to prevent the sea lampreys from ever reaching their 1950s numbers. Researchers are continuing to search for other treatments that reduce sea lamprey numbers to reduce dependence on TFM, which could have negative effects on other fish living in areas where lampricide has been used (Birceanu et al. 2014; USGS NAS 2016). Researchers at the Hammond Bay Biological Station, a partner of Michigan State University, are examining how pheromones (chemicals that animals release into the environment) can be used to alter movements of sea lamprey and to lure them into areas where they can be easily captured or killed (USGS Great Lakes Science Center 2016).
To end, MSU researchers have also begun studying how odors from dead sea lampreys can affect the behavior of living individuals. This is another avenue with which managers can control sea lamprey behavior to eliminate them or prevent them from doing more damage (USGS Great Lakes Science Center 2016). They have recorded the alarm response of living sea lampreys when exposed to these odors, and published them at the following links for your enjoyment:
View from above the water: https://www.youtube.com/watch?v=BxvorkIBbOo
View from below the water: https://www.youtube.com/watch?v=PBvYCBk_ZHM
Works Cited:
Birceanu, O., Sorenson, L.A., Henry, M., McClelland, G.B., Wang, Y.S., and Wilkie, M.P. 2014. The effects of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) on fuel stores and ion balance in a non-target fish, the rainbow troug (Oncorhynchus mykiss). Comparative Biochemistry and Physiology 160: 30-41. https://doi.org/10.1016/j.cbpc.2013.10.002
Great Lakes Fishery Comission. 2000. Sea lamprey barriers: New technologies help solve an old problem. Great Lakes Fishery Commission. Online. Retrieved September 28, 2017 from http://www.glfc.org/pubs/FACT_5.pdf.
Great Lakes Science Center USGS. 2016. Hammond Bay Biological Station. USGS Great Lakes Science Center. Online. Retrieved on September 28, 2017 from https://www.glsc.usgs.gov/sites/default/files/infosheets/HBBS20150818.pdf.
National Ocean Service. 2016. What is a sea lamprey? National Oceanic and Atmospheric Administration. Online. Retrieved September 28, 2017 from https://oceanservice.noaa.gov/facts/sea-lamprey.html.
NY Department of Environmental Conservation. Sea Lamprey Biology. New York State Department of Environmental Conservation. Online. Retrieved September 28, 2017 from http://www.dec.ny.gov/animals/7242.html.
Smith, B.R., and J.J. Tibbles. 1980. Sea lamprey (Petromyzon marinus) in Lakes Huron, Michigan, and Superior: history of invasion and control, 1936-78. Canadian Journal of Fisheries and Aquatic Sciences 37(11):1780-1801.
Trautman, M.B. 1981. The Fishes of Ohio. Ohio State University Press, Columbus, OH.
USGS NAS. 2016. Petromyzon marinus. USGS Nonindigenous Aquatic Species. Online. Retrieved September 28, 2017 from https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=836.