Addressing the issue of invasive sea lamprey within the Great Lakes ecosystems has always been complicated. According to Bryan et al., the introduction of the non-native species into Lake Erie was through the creation of the Welland Canal, which created an opening from the Atlantic Ocean to the Great Lakes in the early 1800s (2005)—however, the existence of sea lamprey was not considered a threat until the 1970s (Sullivan et al., 2003). It is due to the implementation of water protections policies, such as the Clean Water Act in 1972, and restoration of various game fish species during that time created an environment in which allowed sea lamprey populations to flourish where they could not before (Steeves et al., 2012).
While there are no formal policies regarding sea lamprey control, the Great Lakes Fishery Commission (GFLC) along with other informal interest groups, such as recreational anglers and commercial fisheries, have cooperated to address the detrimental presence of sea lamprey on the native wildlife of the Great Lakes. In recent years, the GLFC has begun to advocate for the reduced use of lampricide in favor of physical barriers, which have less of an effect on non-target species that may be sensitive to the chemicals; the downside of barriers is that they are easily swept away by flooding and rain, and are unable to cover wide areas (Bass Fishing, Sea Lamprey Control, n.d.). An alternative method recently approved by the U.S. Environment Protection Agency was the utilization of sea lamprey pheromones as a bio-pesticide dubbed “3kPZS”, its purpose being to attract sea lamprey toward traps (“Sea Lamprey Mating”, 2016), This proves to be an advantage to non-target species because unlike lampricides and physical barriers, which are either selectively applicable or run the risk of capturing or injuring non-target species, it involves the use of a “naturally-occurring, non-toxic chemical” that is specifically targeted for sea lamprey (Klein, 2016). Other methods such as sterile-male-release, in conjunction with the promising outlooks on 3kPZS, are directed toward sea lamprey explicitly and pose little harm to non-target organisms, which is a course of action that I recommend for sea lamprey control in the future.
Current popular methods of sea lamprey control, such as lampricides (a type of highly selective pesticide that target sea lamprey in the larval stage before becoming parasitic), several types of physical barriers that deter adult sea lamprey from reaching breeding grounds, in addition to various others have been highly effective in reducing the sea lamprey presence. The financial burden of maintaining and actively controlling sea lamprey populations, however, can be costly: in 2003, GLFC received $16,037,800 in federal funding from both the United States and Canada (Great Lakes Fishery Commission, n.d.); approximately $3 million of that budget alone was spent on registered-use pesticides (Kinnunen, 2015). The reason why I would advise pushing for strictly sea lamprey-targeted methods of control is due to the non-discriminatory nature of lampricides, barriers, and traps: there is the possibility of capturing federally protected species under protection policy, and thus the actions of the GLFC and other groups need to be closely monitored by the EPA to not cause harm to listed species that may co-inhabit ecosystems with the sea lamprey (Sullivan et al., 2003; Steeves et al., 2012). The use of lampricides has already decreased, and so further steps should be taken to minimize its use as much as possible and focus more efforts onto individual-type methods like sterile-male-release and pheromone manipulation.
Previously addressed, there have been severe conservations about the continued use of lampricide, as lampricides are cost-intensive (Lavis et al., 2003) and its effect on nontarget organisms, raising the concern of environmental protection policies such as EPA and NEPA, which requires agencies to review their methodologies and make sure that they align with the interests of species protection laws. In the past, lampricides have been a great success in reducing the sea lamprey population in Lake Erie to just 10% of its original numbers (Lavis et al., 2003); however, the long-term negative effects have driven the GLFC to pursue alternative methods. One idea that has been minimally tested thus far is the utilization of pheromones to attract sea lamprey to traps, confuse their migration patterns, and further prevent spawning (Steeves et al., 2012; Christie & Goddard, 2003). The most popular alternative method of sea lamprey control, arguably, would be the erection of physical barriers to prevent adult sea lamprey from accessing spawning habitats, and has proven to be the most successful method, other than lampricide (Sullivan et al., 2003). The general public’s perception of using chemicals to treat Lake Erie’s sea lamprey invasion have further supported the idea of reducing the use of lampricide even further (Lavis et al., 2003). Steeves et al. (2012) additionally addresses conflicts that arise from using lampricides during the same time as angler fishers would like to fish game, and in several areas where Lake Erie opens its waters for public consumption may bring forth negative connotations.
Several advantages of the proposed method of constructing more barriers than investing financial resources in lampricide are that building barriers are more affordable and requires relatively little of the sea lamprey control program’s budget, plus barriers have minimal effect on non-target organisms within the same areas of interest of the sea lamprey, falling into compliance with species protection policies (Lavis et al., 2003). Another benefit would most likely be an improved public perception of the sea lamprey control program. A disadvantage of shifting attention from lampricide to barriers would be the intensification of knowledge of sea lamprey migration patterns and places of interest such as sea lamprey-heavy streams within which barriers would most effectively be used (Lavis et al., 2003). The minimally tested method of manipulating sea lamprey with pheromones may yield negative consequences regarding non-target organisms, but has yet to be researched thoroughly; the fiscal requirements of this alternative method have also not been released, and so this may pose an economic dilemma in the future.
References
Bryan, M. B., Zalinski, D., Filcek, K. B., Libants, S., Li, W., & Scribner, K. T. (2005). Patterns of invasion and colonization of the sea lamprey in North America as revealed by microsatellite genotypes. Molecular Ecology, 14(12), 3757-3773.
Great Lakes Fishery Commission. (n.d.). Sea lamprey control in the Great Lakes. Retrieved from http://www.glfc.org/aboutus/budget.php#pr
Kinnunen, R. E. (2015). Sea lamprey control in the Great Lakes. Michigan State University Extension. Retrieved from http://msue.anr.msu.edu/news/sea_lamprey_control_in_the_great_lakes
Klein, K. (2016). So long suckers! Sex pheromone may combat destructive lampreys. Science. Retrieved from http://www.sciencemag.org/news/2016/01/so-long-suckers-sex-pheromone-may-combat-destructive-lampreys
n.a. (2016). Sea lamprey mating pheromone registered by U.S. Environmental Protection Agency as first vertebrate pheromone biopesticide. U.S. Geological Survey. Retrieved from https://www.usgs.gov/news/sea-lamprey-mating-pheromone-registered-us-environmental-protection-agency-first-vertebrate
n.a. (2016). Sea lamprey: The battle continues. Regents of the University of Minnesota. Retrieved from http://www.seagrant.umn.edu/ais/sealamprey_battle
n.a. (Writer), & n.a. (Director). (n.d.). Bass Fishing, Sea Lamprey Control [Television series episode]. In J. Merone (Producer), Outdoor Journal. Colchester, VT: Vermont PBS. Retrieved from http://www.vpt.org/show/11244/1003
Steeves, M., Mullet, K., Slade, J., & Sullivan, P. (2012). Lake-level, five-year plans for achieving sea lamprey control targets in each Great Lake. Great Lakes Fishery Commission. Retrieved from http://www.glfc.org/pubs/SpecialPubs/LL_5YearPlan.pdf
Sullivan, W. P., Christie, G. C., Cornelius, F. C., Fodale, M. F., Johnson, D. A., Koonce, J. F., … Ryan, P. A. (2003). The sea lamprey in Lake Erie: A case history. Journal of Great Lakes Research, 29, 615-626.