Fish biologists working to recover Snake River sockeye say this year's low return--likely to be even smaller than pre-season forecasts--is another bump in the endangered salmon's long road to recovery.
So far, only 19 adult sockeye have crossed Lower Granite Dam. In most years about half of Idaho's sockeye run passes Lower Granite by mid-July.
But this year's small run is not even close to what fish managers were facing in 1991, when these sockeye became the first endangered salmon in the Northwest to be protected under the Endangered Species Act. For a decade, only a handful of sockeye crossed Lower Granite annually. In 1992, only one sockeye--who came to be called Lonesome Larry--was known to return to Redfish Lake in central Idaho.
Five years ago, after decades of work to recover the run, state and federal fish agencies were celebrating the stock's amazing comeback. In 2014, NOAA Fisheries reported more than 600 redds in Redfish Lake, and the Fish Passage Center documented 2,786 adults passing Lower Granite Dam.
"This is a real American endangered species success story," Will Stelle, then-administrator of NOAA Fisheries' West Coast Region said in a 2014 news release. "With only a handful of remaining fish, biologists brought the best genetic science to bear and the region lent its lasting support. Now there is real potential that this species will be self-sustaining again. The sockeye didn't give up hope and neither did we."
In a program funded largely by the Bonneville Power Administration, scientists developed a recovery plan for Snake River sockeye that would see an average of 1,000 naturally spawned sockeye returning to Redfish Lake each year, and similar targets in other Sawtooth Valley lakes.
But since then, fish biologists have suffered significant setbacks in the sockeye recovery program. In 2015, high water temperatures in the Columbia River led to massive die-offs among returning adults.
And from 2015 through 2017, large percentages of sockeye smolts raised at the Springfield Hatchery and released in Redfish Lake Creek perished on their way to the ocean.
In 2017, just 16.4 percent of the Idaho's juvenile hatchery sockeye survived their downstream migration to Lower Granite Dam. Those that made it still had 400 miles and seven more dams to get to the ocean.
Idaho biologists also estimated that--except for one other outmigration--the fewest number of natural-origin juveniles in 15 years left Redfish Lake in 2017.
After the 2017 outmigration, hatchery managers figured out that three years of poor juvenile survival was caused by a difference in water chemistry between the Springfield Hatchery and the creek where the smolts are released. The hatchery's water is hard and has a high alkalinity, while the creek water is unusually soft with a low alkaline level.
John Powell, fisheries research biologist with the Idaho Department of Fish and Game, told NW Fishletter that with only 19 fish crossing Lower Granite Dam as of July 17, it's still too soon to know if the run is just late, or if numbers will be the lowest in more than a decade.
That's not counting 2015, when because of the warm water temperatures, sockeye were transported from Lower Granite Dam to Eagle Creek, Powell said. "It's tough to know how many total fish would have made it back" without the transport operation, he said.
Last year, a total of 276 sockeye crossed Lower Granite Dam, and 113 of them made it to the Sawtooth Basin. Powell said this year's preseason forecast was for 129 sockeye to reach Lower Granite. But last month, fishery managers downgraded their forecast for the entire Columbia River sockeye run by 39 percent.
"We just don't know whether or not the downgrade in the Columbia-wide forecast is going to be affecting our run or not," Powell said. "Normally, we have a number of PIT-tagged fish we can track as they come back and get an idea of where we are in the run. Unfortunately, this year we only have two of those fish, which really doesn't allow us to get a precise estimate."
Historically, sockeye spawned and reared in Idaho's large lakes in the Payette and Salmon river drainages. According to the Idaho Department of Fish and Game, the Payette Lake population was eliminated in the early 1900s due to dam construction on the Payette River. When they were listed, Snake River sockeye were only returning to Redfish Lake, but repopulation efforts have increased their distribution to Alturas and Pettit lakes as well.
Powell noted the low survival rate during the 2017 outmigration is likely a large factor in this year's small return. "The bulk of the fish that should be coming back are those fish that did not survive well during the juvenile migration. So we're missing that component of the run," he said.
But even with a small run this year, Powell said Idaho's sockeye recovery program is still on track.
That's thanks to the captive broodstock program that began in 1991 in an attempt to preserve as much genetic diversity as possible in the Redfish Lake stock.
Powell said fish researchers collected adults from 1991 until 1998, and used the 16 adults that returned during those years as a foundation of their program. They also incorporated freshwater sockeye--or kokanee--that had not migrated out of the lake, and trapped juveniles that were leaving the lake and reared them to adults to develop the new broodstock.
"Every year, we do a lot of genetic work to try and determine what fish we need to spawn to maintain that founding diversity as best we can," Powell explained.
Along with the natural-origin spawners, fish managers raise some of the stock at two hatcheries in order to prevent losing the stock if one location has a catastrophic event.
Powell said while they won't know just how poor this year's adult returns are for another week or more, the good news for the sockeye recovery is that last spring and again this spring, juvenile sockeye survival rates were high.
"We're on the path to having higher returns again," he said.