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Researchers Discuss Declining Columbia Basin Lamprey Numbers, Options For Reversing Trend
Posted on Friday, April 29, 2011 (PST)

Researchers from the Columbia River basin, British Columbia, Finland and Japan gathered in Portland to discuss a common theme – that populations of lamprey have slumped to all-time lows and something needs to be done about it.


The Columbia River Inter-Tribal Fish Commission and its member tribes – the Nez Perce, Umatilla, Warm Springs and Yakama -- sponsored the “International Forum on the Recovery and Propagation of Lamprey” as an information sharing venture. The 2 ½-day session in Portland allowed a face-to-face opportunity for scientists from around the globe to talk about the problems facing lamprey and possible actions to reverse declines. Each country’s representatives gave an overview of the status of the species and an update on related research.


CRITFC tribes hope to restore naturally reproducing, self-sustaining populations within the basin but realize that may not be an option in the near-term.


“As we continue to research adult passage, juvenile entrainment in irrigation diversions, the role of toxicants and predators, habitat loss and other issues, we must also investigate the use of artificial propagation as a research tool and potentially an option to supplement declining populations,” according to an invitation to the forum sent out by CRITFC.


A variety of topics were presented and discussed, including:

-- Factors causing the decline of populations;

-- Restoration opportunities and technologies;

-- Current research in life histories and physiology;

-- Research in propagation facilities and techniques, and

-- Monitoring in the natural environment.


CRITFC’s Bob Heinith told the participants that daytime counts in Bonneville Dam’s fish ladders were as high as a million 40-50 years ago but have only hit 100,000 once since the turn of the century. The count was only 8,622 in 2009 and 11,183 last year.


The daytime counts don’t tell the whole story, since lamprey are more likely to move upstream at night and often through passageways that aren’t monitored. But the trend is obviously downward. Adult lamprey have difficulty negotiating the dam fish ladders, which were designed for stronger-swimming salmon and steelhead.


PIT tag studies have shown that approximately 50 percent of the adult lamprey, which are heading upstream to spawn, disappear from one dam to the next, said CRITFC’s Pacific lamprey project leader Brian McIlraith. Bonneville is the lower most dam in the Columbia-Snake river hydrosystem.


And large numbers of outmigrating juvenile lamprey are impinged and die on screens that have been installed at dams to block salmons from turbines and steer them toward more benign passage routes.


Larval lampreys are referred to as ammocoetes. They spend up to six years burrowed in the sediment, feeding by filtering the water column. Physical cues initiate transformation in the river and Pacific lamprey enter a juvenile stage termed macropthalmia. At this stage the lampreys are silver in color, develop teeth and a sucker-like disc, and form true eyes.


Physiological transformations occur that initiate migratory behaviors and enable them to tolerate sea water. The parasitic Pacific lamprey spend up to two years as adults in the ocean, feeding on fishes and mammals.


The tribes, who have for thousands of years depended on the lamprey for subsistence, have been stirred to action by the sharp drop off.


“They want things to be done,” McIlraith said of tribal members who during the meeting expressed frustration about talks of research and implementation plan development processes. “That’s one thing that came out, the position of the tribal folks. They’re worried.”


“When we come to these meetings we want answers,” the Nez Perce Tribe’s Elmer Crow said.


The lamprey migrations up and down through the rivers take their toll.


“They’re at high risk in the upper basin and less as you go down,” the U.S. Fish and Wildlife’s Howard Schaller said. His agency is amidst an assessment of the status of geographical populations of lamprey up and down the West Coast.


Artificial production of lamprey, the main topic of the forum, is a necessary, though perhaps not favored, path, according to Yakama Nation biologist Bob Rose.


There is a “high level of passion” to see actions taken to improve the survival of naturally produced lamprey, Rose said. But taking such action, such as the ongoing development of passage devices specifically designed for lamprey installing lamprey-friendly irrigation diversion and bypass screens, take time and money.


He described artificial production and translocation as “bridges” to assure lamprey survive as a species until other fixes are in place. The Umatillas have been translocating spawning lamprey since 1995 – capturing them downstream at The Dalles and John Day dams and transporting them upstream for release.


“Those fish spawn” and the tribe has witnessed an increased number of juveniles, McIlraith said. The Nez Perce started translocations in 2007.


“We don’t want to go to artificial production,” Rose said. “But now we’re left with very few choices. Restoration will take a long time.”


Artificial production of lamprey was first tried in the 1980s in Finland and the methods continue to be refined, according to Finnish researcher Kimmo Aronsu. In 1997- 2010 210 million larvae have been out-planted to the Perhonjoki (joki is Finnish for river) and its tributaries.


Japan too has been engaged in artificial production related research for a number of years but research in the United States is just beginning, at Oregon State University and the U.S. Geologic Survey’s Columbia River Research Laboratory in Cook, Wash.


“We’re still in the learning and planning process,” McIlraith said. The largely technical discussions about artificial production research and practice, as well as discussions about lamprey habitat needs, were helpful.


“We hope to continue the discussion with Finland and Japan,” Rose said.


The main causes of severe drops in lamprey numbers are similar in all of countries – the construction of dam and other passage barriers, water management, altered and degraded habitat, toxics and, in Japan’s case, overfishing.


Despite their declining numbers, lamprey are not listed under the U.S. Endangered Species Act. A coalition of conservation groups petitioned for listings but the request was denied in 2004 by USFWS, which said it did not contain sufficient information to warrant further review. The agency then pledged to continue to work with others on efforts to conserve lampreys and their habitats. The listing request was for four species: the Pacific lamprey, the river lamprey, the western brook lamprey and the Kern brook lamprey.


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