Battling a Common Enemy: Service Works with Canadian Researchers to Improve Techniques for Controlling Sea Lampreys in the Great Lakes
BY AARON JUBAR, LUDINGTON BIOLOGICAL STATION
For the past few summers, personnel from the U.S. Fish and Wildlife Service (Service), Ludington Biological Station, have assisted researchers from Canada’s Wilfrid Laurier University in Waterloo, Ontario, in an ongoing research project. The objective of this project is to determine if the ability of larval sea lamprey to resist lampricide varies by season. The lampricide (3-trifluoromethyl-4-nitrophenol, abbreviated TFM) is a selective pesticide that has been used since the 1960’s to control sea lamprey, an invasive species in the Great Lakes.
Utilizing the facilities at the U.S. Geological Survey’s Hammond Bay Biological Station, graduate students Benjamin Hlina and Alexandra Muhametsafina conducted laboratory trials in 2013. Service staff assisted with the on-going project by identifying streams with an abundance of larval sea lampreys and leading the collection effort, which provided thousands of larvae for the study.
"We have observed increases in TFM tolerance as stream water temperatures increase. We believe the trends that we are observing are being caused by increases in larval sea lampreys’ capability to detoxify TFM. Larger energy stores and increased metabolic rates could be contributing factors to seasonal changes in TFM tolerances”, said Hlina.
“We are currently assessing if (larval sea lamprey) metabolism and the detoxification of TFM does increase with increases in water temperature,” continued Hlina. Muhametsafina’s research builds upon this theme, examining both how TFM sensitivity varies seasonally and how larval sea lampreys recover following lampricide exposure at a wide range of water temperatures. “There is evidence to show that recovery after exposure to low concentrations of TFM is faster in warmer water,” said Muhametsafina.
Larval sea lampreys burrow into the stream bottom where they filter feed for 3-7 years before they metamorphose into a fish-eating parasite and migrate downstream to the Great Lakes. Similar to other fish species, sea lampreys are called poikilotherms (“cold-blooded”), and their activity level and metabolism are linked to water temperature.
Larval sea lamprey collection efforts in 2013 focused on the Au Sable River, near Oscoda, Michigan. Service staff worked alongside researchers to collect larvae with backpack electrofishing units. The captured larvae were held in aerated tanks and transported to Hammond Bay Biological Station where they were placed in aquariums containing water that was the same temperature as their natal stream. After acclimating to the aquarium for a few days, the laboratory trials were conducted.
The research, which is funded by the Great Lakes Fishery Commission (GLFC), may have implications for TFM applications and sea lamprey management throughout the Great Lakes. “We hope our findings assist the U.S. Fish and Wildlife Service and the Department of Fisheries and Oceans Canada in applying TFM during the most optimal times depending on seasonal differences,” said Hlina. “By understanding when the optimal application periods are, financial costs associated with TFM applications will potentially be reduced, local abundance of larval sea lamprey will be reduced resulting in adult sea lamprey population reduction, and the potential affects to non-target aquatic organisms will be reduced.”