Biologists fear time running out for Columbia River lamprey

By Kevin McCullen, Herald staff writerSeptember 5, 2010 

Columbia River Basin Indian tribes and federal agencies are scurrying to keep time from running out for an ecologically and culturally important prehistoric fish species.

This year's run of Pacific lamprey is among the lowest ever recorded at Bonneville Dam, and continues a steady annual decline in the number of the eel-shaped parasitic fish returning from the ocean to spawn in the same tributaries that produce endangered salmon and steelhead species.

Dams and diversions in the Columbia River Basin system, degraded stream habitat, chemical poisoning, poorer water quality, competition from non-native fish species, disease and predators are among reasons biologists cite for the plunge of Pacific lamprey.

Tribes and government agencies are trying to stem the decline by making lamprey-friendly improvements to dams and diversions through a 10-year plan embraced by the Army Corps of Engineers, improving stream habitat and more.

But some biologists, particularly those with the tribes, worry the proactive measures are coming at the 11th hour for a fish that dates its origin to at least 350 million years ago.

"Lamprey were largely ignored by (fish) managers prior to 1995, and it's been within the last three to five years that (agencies) have started to do things for lamprey," said Aaron Jackson, Pacific lamprey project leader for the Confederated Tribes of the Umatilla Indian Reservation.

"Is it enough time? I sure hope so. We may be too late. We're looking at our worst run on record, and it follows a bad run last year," Jackson said.

As of the end of August, 20,783 adult lamprey were counted at Bonneville Dam on the Columbia River. By comparison, 19,429 passed Bonneville last year, while the number was 45,104 in 2008, said Bob Heinith, hydro project coordinator for the Columbia River Inter-Tribal Fish Commission.

In the late 1970s, from 350,000 to 400,000 were counted.

The numbers are even lower at Lower Granite Dam on the Snake River, where just 35 passed in 2007 and under 20 have been counted this year.

"They are in serious trouble, no doubt," Heinith said. "We are not getting enough passage at Lower Granite for them to (maintain a sustainable population) because they are not returning as adults to spawn, so we may end up with nothing in the future in the Upper Columbia."

Pacific lamprey are classified as a species of special concern by the U.S. Fish and Wildlife Service, which in 2003 denied a petition to list them on the Endangered Species Act. But the service agreed to put together a plan to bolster lamprey populations to help avoid a potential future listing, said Howard Schaller, project leader for the service's Columbia River Fisheries Program Office and the lead for its lamprey conservation office.

They also are a state sensitive species in Oregon and Washington, a state-listed endangered species in Idaho and a designated tribal trust species. For the tribes, the decline of the lamprey carries deep cultural and nutritional significance.

Indian tribes for centuries harvested lamprey -- which has a high oil content and caloric value -- for food or medicine in the mainstem tributaries of the Columbia and Snake rivers. Lamprey also are part of traditional lore, with stories passed down through the generations.

An unnamed tribal elder spoke of the importance of lamprey in the draft plan. "The foods were here before us ... and they said that the foods made a promise on how they would take care of us as Indians and the eels was (sic) one of those who made a promise to take care of us," the elder said.

In the 1840s, harvests of up to 140 tons annually were documented for commercial fisheries at Willamette Falls near Oregon City, according to the plan.

But tribes began noticing declines in the number of migrators because of a convergence of myriad factors, from dams and other barriers that impeded migration; dewatering or low flows in streams; loss of stream habitat from dredging or other factors; poor water quality; disease; poisoning and more, according to the tribal restoration plan.

Jackson is among those who continue to fish for lamprey at Willamette Falls during a season that typically runs from June 1 to the end of July. Jackson and other tribal members harvested 600 lamprey this year, about half the catch of past years.

The decline of lamprey also has influenced other changes in the basin ecosystem, biologists say.

Eggs of lamprey that spawn in freshwater gravel nests hatch into larvae and drift downstream into low-velocity pools in streams, where they burrow into the sand and gravel.

They live there for three to seven years, filter feeding on algae and other detritus in the water. They begin to move downstream after metamorphosing into sub-adults, and they complete their transformation into parasites by developing a sucking disk before they reach the ocean.

"Ecologically they fill a need nothing else in the ecosystem fills," Schaller said. "Historically, they are a huge biomass filter feeder."

They also historically have served as a prey buffer for juvenile salmon and steelhead, Schaller and Jackson said. Avian predators feasted for years on juvenile lamprey, attracted by their high oil content, Schaller said.

And as adults migrating upstream, they attracted the jaws of sea lions because of their nutritional value and their relative slowness -- lampreys lack a swim bladder, fins or vertebrae and move through lateral undulations of their bodies.

They pull themselves over objects by attaching their disk to it, gradually making their way upstream. But lamprey do not have the same homing instinct as salmon, biologists say, so they may wind up in locations far from their stream of origin -- if they live that long.

"Lamprey have a huge buffer role for predators," Jackson said. "If the avian predators don't have juvenile lamprey, they feed on (salmon) smolts, and the sea lions feed on adult salmon."

Adult lamprey stay at sea for one to three years, but little is known about where they go in the ocean, Heinith and Schaller said. They feed by attaching themselves to a host, moving on to another source after extracting nutrients without harming the host.

"There's a lot more we need to learn about them," Heinith said.

The federal government, states and the tribes are trying to improve conditions for lamprey, although funding for passage improvements at dams and for research is a fraction of the hundreds of millions of dollars set aside in a 10-year, 2008 agreement between the tribes and government agencies for fish passage at the Columbia River Basin dams.

The Corps in 2008 pledged $50 million through 2018 for passage improvements for lamprey at dams and for research, said Rock Peters, fish program manager for the Corps' Northwest region.

Dams and irrigation diversions have taken a toll on lamprey, including turbine and gatewell screens that were designed for juvenile salmon passage but also trap some slower-moving lamprey.

Corps biologists do not know how many lamprey are impinged on the screens, and are trying to develop tags small enough to insert into juvenile lamprey to help in the research, Peters said.

Other improvements on Columbia and Snake River dams are aimed at helping their passage at weir entrances and in fish ladders. At McNary Dam, for example, metal plates were added to each side of the existing salmon passage ports to allow lamprey to rest before attempting to swim upstream through the port, said Mark Smith, lamprey project director for the Corps' Walla Walla office.

Metal plates also were added on top of submerged gratings in the fish ladder to allow lamprey to attach themselves and work their way slowly up the ladder.

"We're also looking at both McNary and Ice Harbor dams at the possibility of reducing flows at night to allow more fish passage," Smith said.

The Confederated Tribes of the Umatilla Indian Reservation have been working on lamprey restoration since the '90s. In 2000, they began a program to reintroduce lamprey into the Umatilla River system, an effort that Jackson said he hopes will yield favorable adult returns in the next five years.

There also could be more research into creation of a lamprey hatchery program.

"If it were not salmon hatcheries, where would salmon be today, especially in the upper reaches of the Basin?" Heinith said. "It may be our last shot to hang onto these critters, by looking at these techniques and continue to make modifications at dams to better passage."

This fall, the Columbia River Basin tribes expect to release a final lamprey restoration plan. Fish and Wildlife also is pulling together a draft conservation plan together with the tribes and states that it hopes to release for review within a month, Schaller said.

"We made a promise to take care of the lamprey the way they have taken care of us," Jackson said of the tribes. "I just hope we can live up to our promise."

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