Blood-sucking sea lampreys threaten Great Lakes ecosystem

Breeding season for 'sea lampreys' Great Lakes Fishery Commission communication director Marc Gaden explains what's being done to deal with the invasive 'sea lamprey.'

TORONTO — The bi-national Great Lakes Fishery Commission is spreading awareness of a blood-sucking fish that has been wreaking havoc to ecosystems for decades.

The sea lamprey, a snake-like fish that has more than 100 teeth and a suction-cup mouth it uses to latch onto and penetrate the scales of other fish. According to Fisheries and Oceans Canada, each lamprey can kill up to 20 kilograms of fish in span of 12 to 18 months, and only 1 in seven fish survive its attacks.

“They can inflict incredible damage,” Marc Gaden of the Great Lakes Comission told CTV’s Your Morning on Monday.

“There’s lots of succulent fish in the Great Lakes that these lamprey like to eat and since there’s nothing keeping them in check, it's this perfect storm of invasion,” he said.

Sea lampreys made their way to North America through shipping canals in the Atlantic Ocean more than a century ago, causing severe damage in the 1950s and early 1960s that led to the collapse of the Great Lakes fishery and nearly destroying the ecosystem. The sea lamprey invasion caused a 98 per cent decline in lake trout at the time, leading to the creation of the Great Lakes Fishery Commission.

The commercial, recreational and tribal fisheries of the Great Lakes have collectively created more than 75,000 jobs in an industry valued at US$7 billion annually, according to the Great Lakes Fishery Commission.

While humans needn’t worry about being attacked by one of these blood-suckers, Gaden says it’s important to recognize the damage they can inflict on ecosystems.

“People need to know that the destructive invasive species did inflict incredible damage on the fishery. They're like a coiled spring and if you let go of all control they’re going to bounce back again,” Gaden said.

Female sea lamprey can lay 50,000 to 100,000 eggs. When the eggs become larvae, they will eat anything that drifts into its path for three to four years until it grows into a mature jagged-tooth predator.

Luckily, Gaden says there have been methods developed to destroy this invasive species that has resulted in the decrease of 95 per cent of the lamprey population in the Great Lakes. The two most effective ways to fight off these parasites include building dams to block the species from spawning and using pesticides. Lampricides are chemical compounds dumped into the lake to directly attack the sea lamprey at their larvae stage.

In its 2017 budget, the Canadian government outlined $8.7 million to control sea lamprey and fund research to better understand them.