The sockeye salmon has rebounded in the Okanagan River system since a low point in the 1990s.
The system includes the internationally-located Osoyoos Lake and is part of the broader Columbia River basin. The rebound is thanks largely to local efforts to improve fish passage, water management and hatchery practices. Sockeye numbers during their annual run have increased from a low of 1,666 passing the Wells Dam in 1994 to a peak of 490,804 in 2014.
While lower than the 2014 record, this year’s sockeye run of 215,997 (as of Sept. 16, 2016) remains remarkably higher than the lows of the 1990s. At the downstream Bonneville Dam near the Pacific Ocean, annual sockeye runs have jumped from 12,678 in 1994 to a peak of 614,179 in 2014. This year, they numbered 342,492 by Sept. 16.
John Arterburn, principal biologist with the Confederated Tribes of the Colville Reservation and IJC Osoyoos Lake Board of Control member, said there are three distinct populations of sockeye within the Columbia River basin: an endangered population of a few hundred in the Snake River, a stable all-natural population in the tens of thousands in the Wenatchee River system, and the largest population of all in the Okanagan River. That latter group was able to rebound spectacularly due to local Native American tribes and First Nations who got the ball rolling in the early 2000s, Arterburn said, eventually bringing the state, provincial and federal governments of the United States and Canada into the effort.
The Colville Tribes and Okanagan Nation Alliance agreed in the early 2000s that they wanted to see sockeye salmon returning to the river system in historically larger numbers, and started plans to make that happen. Initial hatchery programs saw limited success, causing the tribes to refocus on habitat restoration.
“One of the big impediments was the lack of access to habitat in Canada,” Arterburn said. “There were dams built to intentionally prevent invasive species from getting up and invading Canadian waters, and these were operated and maintained to block fish passage.”
The tribes studied what the effects would be if passages were opened up through those dams for sockeye to re-inhabit their native waterways. After about five years, they concluded there would be no negative impacts. McIntyre Dam was fitted with gates to allow fish to pass in 2009 and fishways were opened at Skaha Lake’s dam in 2014. The governments and tribes also were able to develop the “fish and water management tool,” Arterburn said, a computer model that provides information for decision makers to help balance water needs between the fisheries, flood impacts, near-water residents and irrigation demand. The tool has been used in the Okanagan River since 2006.
The tool helps keep water flows stable so sockeye eggs don’t get dried out or scoured away. Since sockeye like to lay their eggs in small gravel, they are particularly susceptible to being dislodged and washed away, Arterburn said. The model lets decision makers see what the flow rates could be based on snowpack, water storage and storms.
While events like rain over snow could still lead to eggs being washed out, Arterburn said the overall result of these efforts is that fish who make it to the river to spawn have a better chance of seeing a larger number of smolts returning to the sea.
Arterburn said they aren’t done yet, however – sockeye are still unable to enter Okanagan Lake at the head of the river in any appreciable numbers, despite it being full of excellent habitat for spawning. He said a fishway there just needs boards installed and the approvals to move forward. He hopes that issue will be addressed by the government of British Columbia in the next few years.
Dean Allan, resource manager with Fisheries and Oceans Canada’s British Columbia Interior office, said the big concern for Okanagan Lake is what impact, if any, sockeye might have on the related kokanee fish species found there. Since both species are now found in Skaha Lake – and a small batch of sockeye have been released into Okanagan Lake. Allan said his agency will be observing the systems as part of a study to see how sockeye interact with the food web and other fish species. Both lakes also are contending with the invasive mysis shrimp, and Allan said they also want to see the interaction between it and both species.
Research scientist Andrew Murdoch with the Washington Department of Fish and Wildlife said the Pacific Ocean is warming, but there is not much data on what sockeye salmon from the Columbia River basin are doing when they get there. The fish seem to be managing with healthy survival rates based on how many are returning to spawn, even though warm ocean water is expected to be hurting their food supplies. Allan added that high water temperatures in freshwater systems can lead to high mortality rates for newly hatched fish.
Arterburn said the boom in sockeye numbers would not have been possible without cooperation from area residents, businesses and governments.
The sockeye salmon’s rebound in the Columbia River basin has been a success story speaking to the value of habitat restoration, fish passage improvements and community members working together with governments and business to make positive change happen.