Wednesday January 15, 2025
The Manitoulin Expositor —
An ancient predator, the sea lamprey, has resurfaced as a growing threat in the Great Lakes, sparking alarm among scientists and fishermen alike. This eel-like invader, unchanged for over 300 million years and a survivor of multiple mass extinctions, is once again leaving its mark—this time in the form of a troubling resurgence following pandemic disruptions.
The Great Lakes Fishery Commission has reported a sharp increase in sea lamprey populations across all five lakes, a direct consequence of paused control measures during the COVID-19 pandemic. Though efforts have resumed, experts warn it will take time to reverse the surge.
“Control efforts in 2024 returned to pre-pandemic levels, but elevated and variable sea lamprey populations should be expected over the next year or two before we see declines,” said Ethan Baker, chair of the commission.
Sea lamprey first infiltrated the Great Lakes in the early 20th century via shipping canals, wreaking havoc on native fish populations. By the 1950s, the invader had nearly collapsed the region’s commercial fishing industry, particularly decimating lake trout populations.
Unlike in their native Atlantic Ocean habitat, where they coexist with hosts as parasites, sea lamprey in the Great Lakes act as ruthless predators. Each lamprey can kill up to 40 pounds of fish during its 12-month feeding period. Using its suction-cup-like mouth and razor-sharp teeth, the lamprey latches onto fish, rasping through scales and feeding on blood and body fluids.