ANN ARBOR, Mich. (AP) — Officials say the population of fish-killing sea lamprey remain at near-historic lows in Lakes Michigan and Ontario but is above target levels in Lakes Huron, Superior and Erie.
The Great Lakes Fishery Commission issued a progress report Tuesday on containing the parasitic lampreys, which invaded the lakes in the last century and threatened trout and other native species.
They use suction-cup mouths and razor-sharp teeth to feed on blood and body fluids of other fish, usually killing their hosts.
Crews use specially designed poisons and traps to control lamprey numbers.
The commission says Lake Huron populations are close to target levels and have held steady the past five years.
Meanwhile, the numbers in Superior and Erie have dropped significantly since hitting near-record highs in 2017.