Canada began releasing water from Lake Okanagan last week to help raise water levels in Lake Osoyoos to aid juvenile salmon that rear in the lake, according to the Washington Department of Ecology.

The extra flow of water that began August 29 and continued to yesterday raised flows in the Okanagan River at Oroville from the normal low flow level of 250 cubic feet per second to over 1,000 cfs, Ecology said.

As the juveniles rear in the northern Washington lake, the adult sockeye headed into Canada have completed their migration, with about 170,000 of the fish making it all the way past Zosel Dam, which creates Osoyoos Lake in northern Washington, and into Canada, according to an August 30 email from Dean Allan, resource manager, BC Interior Area, Fisheries and Oceans Canada.

He also reported that catches totaled about 54,000 and the escapement into Skaha Bluffs Provincial Park was about 12,000 sockeye.

Jeff Fryer, senior fishery scientist at the Columbia River Inter-Tribal Fish Commission, said that of the 215,982 (Sept. 7) counted at Wells Dam on the Columbia River (also see the Fish Passage Center at www.fpc.org), 178,306 made it to Zosel as of Sept. 4. That’s an estimated survival rate of 82.6 percent this year compared to about 10 percent last year, he said.

In 2015 some 186,982 sockeye passed Wells Dam, but most of those did not make it up the Okanagan River and into Canada and are assumed to have died due to extremely hot river conditions. The 10-year average at Wells Dam is 188,063.

Last year in July, the Washington Department of Fish and Wildlife closed fishing in the Okanagan River due to the high river temperatures (see, CBB, July 17, 2015, “Washington State Closing, Restricting Fishing In More Than 30 Rivers With Reduced Flows, Hot Temps,”https://www.www.www.columbiabasinbulletin.org/434536.aspx)

Few fish continue to cross Zosel Dam and the majority of sockeye passed in early to mid-July with more than 38,000 fish crossing the dam July 7 and over 100,000 fish passing July 7 through July 11, according to information from the Colville Confederated Tribes.

“Fish pretty much shot straight up the Okanogan after Wells Dam (with few being caught in Wells Pool fisheries) due to temperatures that hung around 22 degrees Celsius (almost 72 degrees Fahrenheit) for much of the month,” Fryer said.

Sockeye heading up the Snake River and into the Sawtooth Basin in Idaho also had lower water temperatures conducive to migration and passed Lower Granite Dam with no issues this year.

In 2015, Snake River sockeye, listed as endangered under the federal Endangered Species Act, hit a thermal barrier at the dam and those that had made it that far failed to pass. A trap and haul operation transported some 50 of the sockeye from the dam’s raceway to the Eagle Hatchery in Idaho. Some 101 Snake River sockeye made it to Idaho last year and just 44 swam all the way to Redfish Lake on their own.

This year, tailwater temperatures at Lower Granite remained at about 65 degrees during the adult sockeye migration. As of Thursday, some 814 sockeye had passed Lower Granite Dam, while just 420 had passed at this time last year. The 10-year average is 983.

According to Ecology, which manages Osoyoos Lake levels at Zosel Dam, recent flows in the Okanogan River at Oroville have been typically low for late summer (about 250 cfs).

“These flows will rise over the next several days to over 1,000 cubic feet per second as more water is released from Lake Okanagan,” Ecology said in an August 29 news release. “This ‘pulse’ is planned to last for just over a week, after which the river will subside to its usual low conditions for late summer.”

During the pulse, Osoyoos Lake rose 3 to 4 inches as dam operators worked to “feather” increases in flows in the river below Oroville so as to not put too much water into the river suddenly. The river gauge at Oroville is at http://waterdata.usgs.gov/nwis/uv?12439500.

Osoyoos Lake levels are mandated by the International Joint Commission, a board made up of representatives from the United States and Canada. Ecology’s target is to maintain Osoyoos Lake at a level of between 911.5 and 911.8 feet until Sept. 15. After that, the lake will slowly be brought down to winter operations by November, Ecology said.

More information on the International Osoyoos Lake Board of Control can be found at http://ijc.org/boards/iolbc/.

Also see:

–CBB, August 26, 2016, “Cooler Water Continues To Flow In Lower Snake River; Fish Ladder Cooling Now Also At Little Goose,”https://www.www.www.columbiabasinbulletin.org/437373.aspx

–CBB, August 12, 2016, “With Cooler Weather, Snake River Sockeye Showing Decent Numbers Reaching Lower Granite, Sawtooths,”https://www.www.www.columbiabasinbulletin.org/437301.aspx

–CBB, July 22, 2016, “First Snake River Sockeye Of The Year Makes It To Sawtooth Valley; No Passage Issues At Dams,”https://www.www.www.columbiabasinbulletin.org/437179.aspx

–CBB, July 5, 2016, “Compared To Last Year, Cooler Temperatures Seem To Be Giving Snake River Sockeye A Break,” https://www.www.www.columbiabasinbulletin.org/437136.aspx

— CBB, July 1, 2016, “Steps Taken To Cool Warming Lower Snake, Reduce Thermal Blocks During Large Basin Sockeye Return,”https://www.www.www.columbiabasinbulletin.org/437043.aspx

–CBB, June 24, 2016, “Columbia Basin Salmon/Hydro Managers Gear Up For Another Hot Summer: Will Sockeye Get Slammed Again?”https://www.www.www.columbiabasinbulletin.org/436997.aspx

–CBB, April 1, 2016, “Corps Report On 2015 Columbia/Snake Warm Water, Fish Die-Off Will Discuss Actions To Avoid Repeat,”https://www.www.www.columbiabasinbulletin.org/436358.aspx

— CBB, December 4, 2015, “Post-Mortem 2015 Snake River Sockeye Run; 90 Percent Of Fish Dead Before Reaching Ice Harbor Dam,”https://www.www.www.columbiabasinbulletin.org/435642.aspx

— CBB, November 6, 2015, “Report Analyzes Impacts, Causes Of This Year’s Warm Fish-Killing Water In Columbia/Snake,”https://www.www.www.columbiabasinbulletin.org/435505.aspx

–CBB, September 11, 2015, “Snake River Sockeye: Lowest Return Since 2007, Captive Broodstock Program Increases Spawners,”https://www.www.www.columbiabasinbulletin.org/434944.aspx

–CBB, August 28, 2015, “Smoke, Lower Air Temperatures Keep Lower Snake Cooler; 33 Sockeye Make It To Redfish Lake Trap,”https://www.www.www.columbiabasinbulletin.org/434826.aspx

–CBB, August 14, 2015, “Last of Dworshak Water For August? 400 Snake River Sockeye Between Lower Granite, Sawtooth Basin,”https://www.www.www.columbiabasinbulletin.org/434740.aspx

–CBB, July 31, 2015, “First Snake River Sockeye Reaches Sawtooth Basin; Fish Trapped At Lower Granite Taken to Hatchery,”https://www.www.www.columbiabasinbulletin.org/434645.aspx

— CBB, June 12, 2015, “NOAA Fisheries Releases Snake River Sockeye Salmon Recovery Plan: 25 Years Of Actions At $101 Million,”https://www.www.www.columbiabasinbulletin.org/434233.aspx