Oregon Public Broadcasting

A tiny species of lamprey eel, long thought to be extinct, is being reintroduced to a mountain lake in Klamath County Wednesday afternoon.

ODFW

Miller Lake Lamprey

Miller Lake Lampreys were poisoned by the state in 1958 -- in an effort to improve local trout fishing. But a few years ago, scientists found a small surviving population of the little lampreys in a creek.

And now, as Kristian Foden-Vencil reports, they're going to try and reintroduce them.

The Miller Lake Lampreys are their own separate species. And over the last few years, scientists have a developed a new appreciation for what lampreys do.

Roger Smith, a biologist with Oregon Fish and Wildlife, says they filter out plankton in the water and serve as a food source for trout.

Roger Smith: "I'm really excited about this. I mean in your career, you don't get a chance to right a wrong very often. People were responding to the demands of society at the time and society has changed. And this is the right thing to do. It is a unique species. They evolved over thousands of years in this area. And it's kind of nice to get it back to its namesake lake and have Miller Lake Lamprey there again."

ODFW

Smith says when the eels were poisoned with toxaphene, scientists didn't fully understand their life cycles.

All of the adults were killed. But scientists now know young lampreys, known as ammocetes, live in the mud at the bottom of a creek for five years. 

Roger Smith: "The way that they probably survived was more likely that there were some ammocetes in the substrate next to a spring where the toxaphene rich water was not able to get to."

The tiny population was found about five years ago --  three miles downstream from Miller Lake.

Smith says scientists have been waiting for the lampreys to spread upstream. But that hasn't happened.

Roger Smith: "The science team met and made a recommendation that it's probably based on pheromones, which is a scent that the lamprey gives off. The lack of lamprey up in the lake and the lack of pheromones or scent is what's keeping the fish from re-invading."

So today, Smith and his team will use a mild electric charge to coax about 10 percent of the remaining population out of the river mud. They'll put them in a container and drive them upstream.

Roger Smith: "The future looks bright for Miller Lake lamprey. I think people will be able to come to Miller Lake for the next 100 years and see an eco-system that we're trying to restore."

Scientists will study what effect the eels have on the lake as they re-establish themselves.

Online:

ODFW Native FIsh Investigations Project: Miller Lake Lamprey