But wait, aren’t sea lampreys parasitic?
Did that last fact surprise you? Maybe the only thing you’ve heard about sea lamprey is that they are parasitic feeders. Upon returning to freshwater, they are no longer parasitic. Their feeding stops, and their only goal is to make it upstream—sometimes over 100 miles—to tributaries to spawn in the part of the watershed that shows the most promising survival for their young.
During their final life stage, lampreys often become covered in fungus. Still, they swim with all their might to make it to the finish line. Imagine having to run a marathon with multiple obstacle courses at 100 years old that determines the survival of your species! And then, even upon arrival, their job is not done.
They’ll use their mouths to build a nest for their eggs by picking up and moving rocks around into a pile. At last, they will spawn upstream of their newly built rock pile, so the eggs can drift up between the rocks and be protected from predators. These rock nests also create habitat for insects and insect larvae, which is a huge source of sustenance for wildlife in the watershed, including fish and birds. Adult sea lampreys make this final journey despite exhaustion, obstacles, and centuries of habitat alteration. Shortly after it’s final act of engineering, the adult lamprey dies.
When sea lampreys die, they decompose, becoming a crucial part of the watershed’s marine nutrient cycling. “The health of lampreys is linked with the health of aquatic ecosystems and vice versa,” Christina Wang, deputy project leader for the U.S Fish and Wildlife Service’s Columbia River Fish and Wildlife.They are so important for ecosystems, specifically the Connecticut River watershed, that both Vermont and New Hampshire have listed them as a “species of great conservation need.”
Larval lamprey, called ammocoetes, will spend the first few years of their lives remaining sedentary and buried in sandy-silty substrate, feeding on detritus in the water. After five years in the freshwater streams, they become juveniles and begin their journey emigrating to the ocean. When reaching the ocean, they become parasitic feeders, where they have co-evolved with their oceanic hosts. Sea lampreys are also important food sources for a number of fish, marine mammals, and birds in estuarine and marine environments.
Why lampreys get hate in the Lake Champlain Basin
“But aren’t Sea Lampreys invasive?” Confusions often arise on management goals in the Lake Champlain Basin vs. the Connecticut River Basin, and knowing the difference is vital.
In Lake Champlain, their population has reached problematic levels that negatively affect fisheries. Their introduction to Lake Champlain is not clear, some believe they were introduced through shipping containers, while others believe it was a result of the human-made channels from the Atlantic Ocean, and some suggest the species might be native. Regardless of their origin, they are considered a nuisance species threatening native species in Lake Champlain.
Their existence greatly differs between watersheds. In the Connecticut River Basin, sea lampreys are native and have co-evolved with freshwater and marine species since the dinosaurs… It’s important to give them the love they deserve in the Connecticut River Watershed!
Connecticut River