How an eel-like bloodsucking invasive species nearly wiped out fishing in the Great Lakes
The Great Lakes region has a long history of being a hub for commercial fishing and large hauls of various fish species. However, this thriving industry was once threatened by the presence of a mysterious invasive species known as the sea lamprey. Originating from the Atlantic Ocean, these blood-sucking eel-like creatures began wreaking havoc on freshwater fish populations in the Great Lakes basin over a century ago.
One of the first recorded sightings of the sea lamprey was near a popular swimming hole close to Rogers City, Michigan, where a group of youngsters encountered these pesky creatures. Despite the natural barrier of Niagara Falls, sea lampreys managed to make their way from Lake Ontario to Lake Erie by swimming upstream through the Welland Canal and shipping channels. By the late 1930s, these invasive species had spread to Lake Michigan and Lake Superior, posing a significant threat to the ecosystem.
Sea lampreys are known for their suction-cup mouths lined with rows of sharp teeth, which they use to pierce the skin of fish and suck their blood. This predatory behavior led to a decline in fish populations, particularly those targeted by the commercial fishing industry. The Great Lakes Fishery Commission (GLFC) recognized the urgent need to address this issue and embarked on a mission to control the sea lamprey population.
In an effort to combat the sea lamprey invasion, the GLFC supported the production of a documentary titled “The Fish Thief: A Great Lakes Mystery.” Directed, produced, and written by Thomas Lindsey Haskin, the film sheds light on the devastating impact of sea lampreys on the Great Lakes region. With Academy Award-winning actor J.K. Simmons narrating the story, the documentary highlights the importance of fishing in the region and the challenges faced by communities due to the decline in fish populations.
Researchers like Barb Zielinski, a specialist in chemosensory systems, have studied the behavior of sea lampreys and their unique adaptations. Sea lampreys rely on their sense of smell to locate suitable spawning grounds, exhibiting strong movement responses in swimming. Despite their resilience, efforts to control sea lamprey populations have been successful, thanks to the development of lampricide—a pesticide specifically designed to target sea lampreys without harming other fish species.
The implementation of lampricide and the construction of physical barriers have proven to be effective in controlling sea lamprey populations, with a significant reduction in their numbers observed. However, challenges remain, as evidenced by the resurgence of sea lampreys during the COVID-19 pandemic when control programs were limited. As researchers continue to monitor and manage sea lamprey populations, the Great Lakes region remains vigilant in protecting its valuable aquatic resources from these invasive predators.
