LEWISTON- People who grew up playing and fishing on the banks of Idaho’s salmon and rainbow trout rivers 50 years ago may remember digging in the sand to find handfuls of creatures. looking like worms that they could use as bait.
Once very common in the Columbia River basin, the Pacific lamprey is native to the Pacific Northwest and has declined significantly, primarily because it is very difficult for them to navigate dams and reservoirs. Unless you know where to look, most people won’t see lamprey in the wild today. Young fish or larvae known as ammocoetes can spend up to seven years in the sand filtering water for food. They then emerge and migrate downstream in rivers carrying them to the ocean.
As they migrate downstream, they change color from dark brown to silver and develop eyes to see. As their bodies change, they no longer filter water for food but become parasites, latching onto other fish or mammals like whales which will provide them with food and also give them a ride as they grow in the ocean. When ready, adults return to rivers and streams to spawn before dying, much like salmon, except they don’t necessarily head for the specific stream they were born in.
These fish are an important food source in Idaho’s freshwater environments and important culturally and as a food source for tribal communities. Tribesmen traveled long distances to falls and rock structures like Celilo Falls or Willamette Falls in Oregon not only to fish for salmon, but also to pick lamprey off the rocks as they tried to make their way to their spawning grounds.
The lamprey is not recorded in the Snake River Basin, but due to its precipitous decline, the Nez Perces developed a translocation program for lamprey populations in the Snake River Basin to prevent extinction regional. Adult lampreys that are trapped at Bonneville, The Dalles, and John Day dams on the Columbia River are either trucked and released directly into certain major rivers upstream of the Lower Granite Dam in the fall, or taken to the Nez Tribal Hatchery Pierced on the Clearwater River. where they are cared for all winter and released the following spring. The Nez Perce Tribe focuses on releases into streams where there is historical information documenting their past presence and good habitat to promote future success. The Potlatch River Basin is an example.
For the past two years, the Nez Perce Tribe and Idaho Fish and Game have collaborated and released adult lampreys into the East Fork Potlatch River near Bovill, Idaho. This year, a new site on Big Meadow Creek near Troy, Idaho was added to the list of Potlatch River tributaries receiving adult lampreys. All adults were tagged with a Passive Integrated Transponder (PIT) tag prior to release. With these tags in place, we can document if these fish remained in the tributaries after their release, giving us an idea of whether or not they spawned.
Lamprey are released into these waterways due to the active habitat restoration programs taking place there. These two areas are central watersheds for habitat restoration that benefits rainbow trout and lamprey (Making steelhead habitat complex | Idaho Fish and Game). The new release site at Big Meadow Creek is located upstream of a road culvert which was modified in 2018 and now provides better fish passage for rainbow trout and hopefully now too for lamprey (genetic testing shows large increase in rainbow trout populations in Potlatch River tributary | Idaho Fish and Game).
These efforts are not enough to return the lamprey to its historical abundance and distribution, however, the program is working. Researchers from the Nez Perce Tribe and the Columbia River Inter-Tribal Fish Commission Genetics Laboratory documented the birth of juvenile lampreys as part of this effort and recently documented the first adult lamprey ascending the Snake River that was born in the frame of the translocation. program.