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New Fish Passage For Umatilla River Lamprey Helps Spur Higher Than Expected Adult Return
Posted on Friday, October 14, 2011 (PST)

It may not seem like a lot, but the return of 138 lamprey to a specially designed ladder on the lower Umatilla River, an eastern Oregon tributary of the Columbia River, has surprised fisheries experts who expected smaller returns that would take much longer to materialize.


“We’re trying to figure out why we have so many more in the Umatilla,” said Aaron Jackson, lamprey technician for the Confederated Tribes of the Umatilla Indian Reservation, the tribe leading an effort to restore the prehistoric fish.


Meanwhile, the U.S. Fish and Wildlife Service this week released its Pacific Lamprey Assessment and Template for Conservation Measures, the first phase of a broader initiative to conserve and restore the species throughout its range. (See story: “USFWS Releases Pacific Lamprey Assessment, Template For Restoring ‘Priority Species’ In Columbia Basin”


Additionally, the U.S. Army Corps of Engineers has established a Juvenile Larval Lamprey Work Group that likely will consider a number of methods for monitoring passage at Columbia River dams, said Jackson, a member of the working group. Those methods could include tagging juvenile lamprey and then following their migration downstream as 5-7-inch juveniles to the Pacific Ocean and back 10-30 months later as adults to their spawning grounds throughout the Columbia River Basin.


Also, a Tribal Lamprey Management Plan is going through final editing before it will be released by the Columbia River Inter-Tribal Fish Commission in the next few months.


“It’s (Tribal Lamprey Management Plan) calling for serious attention,” Jackson said. “The funding gates need to start opening so we can learn more about lamprey. At one time there were probably several million in the Columbia Basin and it’s not unfathomable that we could have as many as 20,000 in the Umatilla River. The populations are depressed and we’re struggling to figure out why that is.”


Jackson said restoring lamprey in the Columbia River Basin will require passage improvements for both migrating juveniles and adults. Juveniles have an option of using a screened salmon bypass system, where they often are impinged in the screen mesh, through “strike and shear” turbines, or over spillways.


“We’re trying to figure out the best route,” Jackson said.


This year, again for an unknown reason, the number of adult lamprey returning to the Columbia River from the Pacific Ocean is higher than normal. This year’s run of an estimated 50,000 lamprey is twice the number that passed over Bonneville Dam last year.


Those numbers are estimates, Jackson said, because lamprey counting occurs for about 16 hours during the day, and not during the night when lamprey are most active.


“We want 24 hour counts,” Jackson said. “The four tribes (CRITFC members) have asked the Corps to fund CRITFC and the Washington Fish and Wildlife Department that oversees the counting at The Dalles and John Day dams.”


Regardless of the total numbers, the run is reduced dramatically before it reaches the Umatilla River as the lamprey navigate The Dalles and John Day dams, and enter other tributaries (John Day, Deschutes, Klickitat, Wind River rivers, and Herman Creek).


“We’re losing 50 percent at every dam,” Jackson said. “That means this year that through attrition we’re down to 25,000 at The Dalles and then 12,500 at the John Day.”


Without proper monitoring, it’s hard to say exactly how many are reaching the Umatilla.


“I’d like to say the adult returns are from our translocation program, but it’s difficult to say without tagging or some kind of detection,” Jackson said. “We’re talking about PIT tagging juveniles in the Umatilla and if we get them back as adults then we can say they were reared in the Umatilla.”


Although they can’t say whether or not the returning adults were spawned in the Umatilla from released adults (annually as many as 600 to as few as 68, depending on the number gathered from John Day Dam) in the headwaters over the last 11 years, the Umatilla Tribes can point with “excitement” to this year’s return, which is eight times higher than last year’s count of 17 adults.


The increase can be attributed to a number of positive things, Jackson said, not the least of which is higher flows in the lower three miles of the Umatilla River. That section of the river often dries up between May and October, just before and just after the peak migration of lamprey, which cross over the John Day Dam in a July-to-August window. To remedy that low-water problem, the Bonneville Power Administration is funding baseline flows of about 75 cubic feet per second through the federal Umatilla Basin Project, which exchanges water from the Columbia River for farmers who leave the same amount in the Umatilla for fish during the spring growing season.


Jackson believes that extra water is pushing out into the Columbia juvenile lamprey pheromones (a chemical substance that triggers reproduction) that attract adult lamprey moving up the Columbia.


Those pheromones were stopped at Three Mile before the additional BPA-funded flows during that peak adult migration period. Once the adults entered the Umatilla River they also were stopped at Three Mile, a concrete diversion built by the federal government to irrigate lands in the early 1900s, which, incidentally, caused expiration of salmon.


But now the new lamprey ladder on the east side of the river is giving tribes hope that lamprey can make a comeback. Built with funding from BPA’s 10-year Accords Project Funding and a U.S. Fish and Wildlife Service wildlife grant, the lamprey ladder project is designed to see if lamprey can better reach waters above diversion dams, in this case Three Mile Falls Dam. Prior to the lamprey ladder, the fish – sometimes called eels – had to use outdated salmon bypass ladders or suck their way up and over about 20 feet of concrete to the other side.


“Of the 138 we counted, 115 used the new ladder and 23 used the old salmon fish way or climbed the dam,” Jackson said.


The fish ladder, with sharp 90 degree corners, was not suited to lamprey, which rely on the suction of their mouths to reach the waters above Three Mile Falls Dam. The new ladder has rounded edges with a 45 degree climb so lamprey can keep their attachment up and over the structure.


Although the value of the fish has been generally dismissed, the adaptable lamprey is a traditional and ceremonial food for tribes throughout the region.


“The tribes have a vested interest because lamprey are culturally significant,” Jackson said. “They are a prized fish to us.”


For years, Jackson said, state and federal agencies have given short shrift to lamprey in favor of efforts to protect and restore salmon and steelhead listed on the Endangered Species List.


Historically, the only use for lamprey has been as bait for sturgeon or as fish meal to feed young fry in fish farms. In the 1930s tons were collected on barges from the Willamette, then ground into fish meal.


Jackson is hopeful that results from places like Three Mile and subsequent research and monitoring will give lamprey a chance to continue a historic lifecycle that as adapted through the ice age, eons of volcanic disruption, even the Missouri Flood that created the Columbia River system.


“Salmon have been around for 10 to 13 million years. Fossil records show that lamprey have been on earth for 530 million years, since before the Jurassic Period,” Jackson said, noting that a Columbia Basin Fish And Wildlife Authority “white paper” is to be published soon that will provide the research behind the historic claim.


“Lamprey predate dinosaurs,” Jackson said. “These critters are really old and it bothers me to think that in my lifetime they could potentially go extinct. It’s not acceptable; it’s unfathomable to think they’ve been around that long and could be gone within my lifetime.”

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