Reason for optimism
Dr. Fryer noted water temperature and ocean conditions as factors but is hopeful about other trends that portend better returns in the future. Spawning and rearing habitat in the Okanagan River and in the headwaters lakes is steadily being improved. Much of the credit for that goes to the Okanagan Nation Alliance (ONA), a First Nation in British Columbia that has been working to improve sockeye dam passage, habitat, and natural production in the Okanagan River and its tributaries. The improvements include channel restoration and construction of spawning beds, and better access to spawning habitat as the result of fish passage improvements at two dams – McIntyre and Skaha in British Columbia.
Additionally, the ONA has a sockeye hatchery in Penticton to spur sockeye restoration in Skaha Lake and for juvenile fish releases into Okanagan Lake. The hatchery is funded by the Grant and Chelan public utility districts as part of their effort to mitigate the impacts of the four dams they own on the Columbia. These returns currently comprise about 10 percent of the run. A goal of the ONA is to see fish pass over Penticton Dam, 664 miles from the ocean, which would open up 84-mile long Okanagan Lake to sockeye production for the first time since the early 1900s.
Another reason for increased escapements is reduced harvest levels due to efforts to protect ESA-listed Snake River sockeye. The Columbia sockeye run used to be managed for an escapement of about 25,000 on the Okanagan River spawning grounds with harvest allowed of any “surplus.” An escapement of only 25,000 arguably could not produce a return (to Bonneville) of 500,000 as happened in 2015. Based on the large escapements in recent years, biologist Dr. Kim Hyatt of the Department of Fisheries and Oceans Canada estimates a more appropriate escapement goal is more than 100,000 sockeye for Osoyoos Lake alone. The international border passes through the lake.
Fryer noted a model funded by the Douglas County Public Utility District, which owns and operates Wells Dam, the last Columbia River dam Okanagan sockeye cross on their journey to spawn (there are dams on the Okanagan River, too), is improving management of Okanagan River flows to balance competing interests for water such as agriculture, flood control, recreation, the needs of resident kokanee, and sockeye. The Grant and Chelan public utility districts, in addition to the Bonneville Power Administration, have helped fund juvenile and adult monitoring programs that provide data used in the model to better manage Okanagan sockeye. Bonneville funding comes from a Columbia Fish Accords project with the Columbia River Inter-Tribal Fish Commission.
Despite the steady decline since 2007, the future looks hopeful as habitat and passage improvements continue, as water management in the Okanagan improves, and as the fish shift their run timing in response to a warming river. Fryer said elders of the Okanagan Nation recall that sockeye historically consisted of two runs, one in July and the other in May (the latter possibly bound for Okanagan Lake), and so perhaps the earlier run may be re-establishing.
But there always is the unexpected, such as the weather. Hot weather in June this year warmed the Okanagan River, stopping sockeye migration when few fish had passed Wells Dam. However, in late June through the middle of July the weather cooled, resulting in a high rate of passage into Osoyoos Lake for the early-migrating run. Now, as the peak of the run passes Wells Dam, temperatures have been warming, and that likely will set up a thermal barrier in the Okanagan River. The question is whether this barrier stays until late August or even September, requiring sockeye to hold in the pool behind Wells Dam with higher mortality than if they made it to Osoyoos Lake.
Or, Dr. Fryer said, will there be a dip in temperature that is large enough and long enough for sockeye to make a run up to the North Basin of Osoyoos Lake. (The southern and central basins of Osoyoos Lake are warm and shallow, offering no habitat for holding until spawning.) Or also, he added, “will the sockeye be lured up the Okanagan River by a short dip in temperatures, only to have an increase in temperature snap the trap shut before they make it to the North Basin resulting in high mortality, as happened in 2015 several times and has been observed in several other years as well.” He said these are the risks faced by the Okanagan fish every year.
“The reward, if they make it, is a much-improved spawning habitat in perhaps the most productive sockeye lake for its size in the world,” Dr. Fryer said.
As a sockeye expert, Dr. Fryer said the Okanagan run is amazing to watch.
“Every year they run a gauntlet of nine mainstem dams plus two or three Okanagan River dams on both upstream and downstream migrations with adults facing extremely high temperatures as well. Yet this run has not only persisted but thrived,” he said. “This time of year, I’m frequently looking at dam counts, temperature data, and PIT tag detections to try to figure out how the run is responding to the hostile conditions that Mother Nature throws at it. And nearly every year, enough of the returning adults figure out a way to beat the high temperatures and survive to spawn to keep this run not only persisting, but thriving. No other sockeye stock in the world could survive the temperatures faced by this stock. It is truly amazing to see.”