The sea lamprey is the focus of the most recent episode of Discovery Channel's "Dirty Jobs"
Mike Rowe, the show's host and willing participant in these 'dirty jobs,' will shadow scientists as they attempt to corral and control the lamprey population in the Great Lakes.
The sea lamprey was one of the earliest species to travel the shipping canals dug to allow transport of goods from the lakes out into the St. Lawrence Seaway. These waterways allowed the lamprey to enter and colonize the lakes back in the 1920s.
Lamprey attach themselves to large fish and suck the life out of them. By the 1950s, the lamprey had significantly depleted the lakes of large, predator fish. This allowed the population of alewives (a smaller fish) to explode.
Controlling the lamprey population and restocking the lakes with trout and salmon allowed some semblance of balance to return.
(Photo is from the Inland Seas Education Center located in Suttons Bay, Michigan)