Wednesday, April 13, 2016
The Pacific Lamprey may be on the rebound upstream of the former Condit Dam site on the White Salmon River.
The return of the lamprey is seen as an important step in habitat restoration since the removal of Condit Dam, as is lamprey conservation and the partnership between the United States Fish and Wildlife Service (USFWS) and the Yakama Nation.
Before the removal of the Condit Dam in 2011, Pacific Lamprey weren’t found above Condit Dam. During its existence, the dam blocked the passage of fish migrating upstream for over 100 years.
“I’m glad to hear that Pacific Lamprey are making their way above the old dam site,” said Ralph Lampman, a biologist with the Yakama Nation FRMP, Pacific Lamprey Project. “We did capture smaller larvae at 13.1 (river site) and all of the larger larvae were Western Brook Lamprey (there),” said Lampman.
The Pacific Lamprey larvae, which are the size and shape of a small earthworm, are likely offspring of adults spawning in previously inaccessible habitat. The documentation of Pacific Lamprey naturally recolonizing in the White Salmon River is one of few.
“This is a good day,” said Patrick Luke, Yakama Nation Tribal Councilman. “We are recognizing asum (lamprey) making their mighty return to Mitula Wana (White Salmon).” The Pacific Lamprey bares cultural importance for the Yakama people who used to hunt the fish throughout the Columbia River basin before populations dropped and fishing was limited to certain sites.
Staff from The Yakama Nation and USFWS began monitoring lamprey distribution in the basin in 2007. Prior to removal of the dam, surveys performed by USFWS biologists yielded no Pacific Lamprey above the dam, only below. However, non-migratory western brook lamprey were detected both above and below the dam.
Lamprey have a unique life history and important ecological role in the river. The lamprey’s return should broaden the natural diversity of the river and improve conditions for other aquatic species, explained Lampman. “There’s multiple roles they play in ecology,” said Lampman, “adults bring back nutrients from the ocean and drop that into the stream.”
Their return also means the river will develop a better, more well-rounded, nutrient system built by the salmon returning in the fall and winter, and the lamprey in the spring and summer. “If you just have one, or the other, you don’t have the whole nutrient system coming back to the stream,” Lampman said.
“Because of the critical ecological role that lamprey play in rivers of the northwest and the strong tribal cultural importance, the return of lamprey to the White Salmon (makes) this a brighter day,” said Howard Schaller of USFWS.
The fish are filter feeders which burrow down in fine sediment to sift out food during the first few years of existence. “They act like worms in the forest, where they break down nutrients and recycle nutrients,” Lampman explained.
Although Lampman was supportive of the findings, he suggested the fish may be on their way to another creek. “The basin does not hold a large area of larval lamprey habitat in the mainstem,” said Lampman, “and unless they are making their way into Trout Lake Creek, recolonization will be at limited quantities and levels for the foreseeable future.”
In the summer of 2015, as part of post dam removal monitoring, USFWS surveyed for lamprey in several watersheds as well as the mainstem of the White Salmon River above and below the former dam site. Pacific Lamprey were found at three locations upstream of the former dam site, around river mile four, in areas previously inundated by the Northwestern Reservoir.
Finding the lamprey gave the USFWS and Yakama Nation a unique opportunity to monitor a potentially naturally-recolonizing population of Pacific Lamprey and an aquatic community’s response to dam removal. “All lamprey need is a chance to recolonize on their own,” said Councilman Luke.
More monitoring will take place, Lampman explained. “In the White Salmon basin we’re just taking more of a laid back approach and just letting it seed on its own.”