It starts raining just as two trucks hauling juvenile salmon arrive near the end of a gravel road at Chief Joseph Dam in the Central Washington town of Bridgeport on Friday, May 6. The trucks, driven by scientists from the United States Geological Survey (USGS) and Coeur d'Alene Tribe Fisheries Program, stop with the last group of salmon from what was initially about 5,000 total summer chinook reared at a Coeur d'Alene Tribe hatchery in Plummer, Idaho.
This will mark the final release of juvenile salmon whose journeys down the Spokane and Columbia rivers are being tracked by several Inland Northwest tribes in hopes of understanding the viability of returning salmon to their once free-flowing homewaters.
With the haul of young salmon now on the road below Chief Joseph Dam (the main portion of which opened in 1955), a team of volunteers gets ready to start hauling buckets of fish down the steep hill to the water, navigating over rip-rap boulders.
Casey Baldwin, a research scientist for the Confederated Colville Tribes, is in waders and prepared to spend some time in the water. He directs the group how to line up and heads down to the water's edge, where he'll delicately empty each bucket into the water across the way from the dam's powerhouse outflow.
"We're trying to monitor their survival in these different reservoir reaches," Baldwin explains, "and their survival as they go through the dam."
There are stairs down to the water nearby that would be much easier to use to release the salmon, but whenever the spill isn't running over the top of the dam, the water running through the powerhouse creates a slight back-current, Baldwin says. The team doesn't want to risk confusing the fish with an eddy pushing them toward the dam when they should swim away from it, so roughing it to carry the buckets over the slippery rip-rap it is.
Other releases from this group of chinook have already taken place upriver along the Spokane and Columbia. This release is timed roughly to coincide with those earlier groups as they make their way through the turbines at Chief Joseph. With fish released above and below the dams, scientists will be able to tell how well the fish survive going through or over each dam compared to those that were released below each specific dam.
The work is part of the second phase of a roughly 20-year plan worked on by the Spokane, Confederated Colville, Coeur d'Alene and Kalispel tribes, along with the Kootenai Tribe of Idaho, USGS, and other interested parties.
The hope is to ultimately understand what it will take to reintroduce the salmon to a system that's been blocked to them, in some cases for more than 100 years.
Photos from Inland Northwest tribes' salmon release at Chief Joseph Dam in Central Washington
At some stages of the journey, the fish will only have the option to go with the water through massive turbines used to generate electricity. For example, at the enormous Grand Coulee Dam, fish won't likely see the opportunity to take spilled water onto the next stretch of river, as the structure maintains its reputation as the largest hydropower producer in the country by directing most water through its powerhouses.
To better understand the exact outmigration of the juvenile fish in this study, a fraction are tagged with expensive (we're talking hundreds of dollars per fish) acoustic tags that enable scientists to pick up their signal from hundreds of meters away. The batteries in those tiny tags are only able to last maybe 75 days or so, Baldwin explains, but they should last most of the journey downriver.
On Friday, roughly 75 fish have the acoustic tags, which were surgically implanted the day before. The tags will regularly send out a long alphanumeric code, unique to that fish, to receivers set up along the rivers.
Those fish, along with about 900 others that don't have acoustic tags, are also tagged with PIT (Passive Integrated Transponder) tags that don't require batteries and can be picked up when fish are within a few feet of detection equipment at dams lower down the river.
The PIT tags are very accurately monitored when adult salmon are returning and using fish ladders to climb over the dams lower in the system, Baldwin says. Some of those dams also include PIT detection equipment in bypass streams that are designed to help juvenile salmon get around dams on their way out to sea, so some of the study fish could be detected by that monitoring system as well.
"The release timing was to match the natural and the hatchery releases of chinook in the Columbia Basin," Baldwin says. "[Acoustic tags] allow us to evaluate the fish in places like these big reservoirs around dams that don't have juvenile bypasses and they're not wired for PIT detection."
The acoustic tags pinging off arrays may also give a sense of how the fish approach each dam, whether that's from river right or river left, or whether fish prefer going over the dam through spill (when that opportunity is available) or through powerhouses, Baldwin says.
"Every five seconds it pings saying, 'This is who I am,'" Baldwin says. "The receiver reads that and then says, 'OK, that fish was at this spot, on this day.' By doing that on down through the system, we're able to model survival and, to some degree, behavior."
Aaron Penney, supplementation biologist for the Coeur d'Alene Tribe's Fisheries Program, stands in the back of one of the two pickup trucks, next to a tank full of young salmon. As volunteers run full buckets down the hill and return with the empties, Penney reaches into the tank to refill the buckets with a little water, then uses a net to gather the next group of juvenile fish that will be passed down to the water.
Usually, he says, they're able to hook a hose up to a valve on the side of this tank and release fish directly into a body of water, but this study is bringing salmon to some locations for the first time in decades, where crews have had to get clever with their use of buckets, rope and manpower.
Their work is already paying off.
At least two of the fish the tribes released in Latah Creek (also known as Hangman Creek) near Tensed, Idaho, crossed Bonneville Dam on April 3, Penney says. After Bonneville, the fish traverse the estuary and make their way to the Pacific Ocean, where, if they're extremely lucky, they don't become food and instead mature, grow for a few years, then turn around to fight their way upstream to spawn and die.
For the Chief Joseph Hatchery, the smolt-to-adult rate of surviving fish that return to the area is somewhere close to 1.5 percent, Baldwin says. That can vary from year to year, with ocean conditions playing a major factor.
This year's release will mostly help researchers understand the survival rate for the juveniles on their way out, Baldwin says. But as only a few of the roughly 5,000 total fish may ever return as adults, the group likely won't create a sample size large enough to study the return journey.
However, the tribes are already working on raising fish for a larger release for next year, and ultimately they hope to increase release numbers to something closer to 100,000 fish or more, Baldwin says. One hangup is that most hatcheries are already rearing fish at or near capacity, so this project may require the creation of more space to raise the fish before they're released.
While the agencies that run the dams aren't officially involved in funding the work yet, some leaders hope that might change. The Washington State Legislature this year agreed to put $3 million toward the project, explains Cody Desautel, the Confederated Colville Tribes' Natural Resources director.
"We think there's a lot of potential up here because this is where the cold water comes from."tweet this
Canadian government agencies and First Nations there are also looking at what it might take to return salmon even further upstream into the cold waters they once used to reach, Desautel says. Early conversations with those groups have started to ensure the work on each side of the border can be useful to everyone.
"Particularly in light of climate change, we have warming climates, warming water temperatures and that's extremely detrimental to salmon," Desautel says. "We think there's a lot of potential up here because this is where the cold water comes from. ... The river functions as one system, the fish eat as one system."
Understanding that system with comparable data should help leaders along the intertwined waterways find solutions, he says. Once larger questions are answered, the groups may better be able to pitch who should be paying for those solutions and what timeline would help manage costs.
"It's questions that haven't been asked before, so it's not just policy work but legal work to ask what's allowable," Desautel says, "and if there are fixes, to see what those would be and where those requests for potential legislation might come from."
The 20-year plan could also wrap up sooner should the research prove that salmon don't need extra help on their way downriver in areas such as the Spokane River, where spill over the dams is already common in the spring, Baldwin says.
"Spill tends to be very fish friendly in terms of getting them downstream quickly," Baldwin says. "We don't know that it is for sure yet at those facilities, but if we do learn that bypass may not be necessary, it could save a chunk of time." ♦