KLAMATH FALLS, Ore. -- On August 4, ODFW biologists will reintroduce the Miller Lake lamprey, once thought to be extinct, back to Miller Lake.
According to Roger Smith, ODFW fish biologist in Klamath Falls, biologists will collect immature lamprey from a nearby population in Miller Creek and release them into Miller Lake.
“This is a major step in our efforts to restore the lamprey to an important part of its native range,” he said.
The world’s smallest predatory lamprey, it’s approximately 4-inches inches long, the Miller Lake lamprey was considered extinct after a chemical treatment in 1958 eliminated the only known population from Miller Lake.
“Anglers, and fishery mangers, were concerned that the predatory nature of the lamprey and an overabundance of tui chub were having a severe impact on the rainbow trout fishery,” Smith said. “So they decided to treat the lake with chemicals to remove them.”
Then in 1992 two Oregon State University researchers caught a Miller Lake lamprey during a fish survey of the upper Williamson River. Since then, extensive surveys have turned up several small populations in Miller Creek and the upper Sycan River.
However, the Miller Lake lamprey has never been found again in Miller Lake.
Since its elimination in 1958, and its rediscovery 44 years later, scientists and conservationists had developed a new appreciation of the Miller Lake lamprey. In 2005 ODFW adopted a recovery plan for the lamprey, and in 2006 it was identified in the Oregon Conservation Strategy as a species in need of conservation.
While the Miller Lake lamprey is not on the brink of extinction, scientists are concerned because of its limited range and absence from the lake. The lamprey are present in only a few small streams in the Klamath Basin, and even then only in very small sections of the streams. For example, Miller Lake lamprey inhabit less then 2 miles of Miller Creek.
In 2005, biologists took the first step toward restoring the lamprey to its native range when they removed an old lamprey barrier between the Miller Creek population and the lake. They hoped eventually the creek population would find its way back to Miller Lake.
But after five years and still no lamprey in the lake, scientists are moving to Plan B.
“Lamprey migrate back to their natal streams from phermones or scents given off by other lamprey,” Smith said. “With no lamprey in the lake there are no pheromones or scents to attract other lamprey.”
In the next two years, scientists will electro shock the waters of Miller Creek, temporarily stunning immature lamprey, and collect up to 10 percent of the lamprey they find. They will then move them to Miller Lake.
Scientists hope the immature lamprey (called ammocoetes) placed at the outlet of the lake will re-colonize the lake, and attract new lamprey as well.
Despite angler concerns that led to the elimination of lamprey from Miller Lake in 1958, biologists do not expect the reintroduction of the lamprey to have a significant effect on trout populations or fishing in the lake.
“We have several examples of healthy trout and lamprey populations coexisting elsewhere in the Klamath Basin,” Smith said. “While the adult lamprey do feed on trout, they do not kill the trout and leave just a small round scar.”
”In addition, lamprey also can be a significant food source for larger trout,” Smith added.
More information about Miller Lake lamprey:
Miller Lake lamprey spawn in the late spring in clean gravel and sand redds; adult lamprey die after spawning. Immature lamprey are called ammocettes and live for five years burrowed in sediment and feeding on suspended microorganisms and algae. As adults, lamprey become predators by attaching to fish with a sucking disk and feeding on the flesh that is rasped out under the disk. Adult lamprey live for one year before spawning. Historically, adult lamprey in Miller Lake fed on tui chub and several species of trout.