Sockeye return to Deschutes River

That's a significant improvement over recent years — since 2010, annual returns have ranged between 19 and 86 fish.

"We are not pointing to this and saying mission accomplished, but at the same time it's a really great result for 2016," said Steven Corson, a spokesman for complex co-owner Portland General Electric. "Our goal is to have sustained and harvestable fish runs, but we are still in the beginning stages."

The dam complex is owned by PGE and the Confederated Tribes of Warm Springs. It stretches over about 20 miles of the Deschutes River west of Madras.

The complex was originally designed in the 1950s and 60s to include fish passages, but the passages were not effective. Round Butte Dam owners are now trying to reintroduce spring chinook and steelhead in addition to sockeye salmon.

Corson said salmon returns are often unpredictable and the reintroduction efforts are still in the early stages.

More than 93 percent of the sockeye originated in the Middle Deschutes basin, according to genetic testing received by Portland General Electric in January. Most of those came from a lake created by the Round Butte Dam called Lake Billy Chinook.

While waiting for new data, scientists continue to monitor water quality and work on habitat-improving projects in the area.

"It's an ongoing, scientific-based effort to maximize the potential for a successful year," Corson said.