TRAVERSE CITY, Mich. — Federal scientists say parasitic sea lampreys may have established a self-sustaining population in Michigan’s Inland Waterway, a 38-mile-long chain of lakes and rivers in the northern Lower Peninsula.

The eel-like lampreys suck bodily fluids from fish. They’ve been a constant threat to trout and other native species in the Great Lakes since arriving in the last century.

They spawn in rivers, and when fully grown migrate to the lakes.

Lampreys have long been present in rivers that feed Burt and Mullet lakes, which are part of the inland waterway that is popular with anglers and boaters.

But Nick Johnson of the U.S. Geological Survey said Thursday there’s mounting evidence that some lampreys are spending their lives in those lakes instead of migrating to Lake Huron.