Sockeye return in record numbers

PORTLAND – Sockeye salmon, an oceangoing species that starts and ends its life hundreds of river miles inland, are swimming up the Columbia River this summer in numbers unseen in five decades.

No one knows exactly why. Some say it’s because federal courts ordered the release of extra water over dams in 2006 and 2007 to make passage easier when the fish were young and migrating to sea. Others cite improved ocean conditions.

The undisputed fact: Sockeye salmon runs have hit historic post-dam-construction highs this summer in the Columbia and Snake rivers, an unexpected positive sign for a species close to being written off in parts of the Pacific Northwest’s largest river system.

The fish counts, which have surprised the experts, include nearly 215,000 red salmon counted at Bonneville Dam through Tuesday, the biggest number of adults returning from the ocean since 1955.

Most of those fish followed the Columbia River up to Wenatchee and Osoyoos lakes, while a far smaller number – representing the system’s most endangered run – swam on to Lower Granite Dam on the Snake River. With the journey past the dams nearly over, the count of returning adult sockeye there topped 800 through Tuesday.

That’s a tiny number in relative terms, and the Snake River fish still have to make it home to central Idaho. But it’s the highest sockeye return recorded at Lower Granite since it was built in 1975, and nearly 25 times the average return of the last 10 years. Ten years ago, two sockeye came back.

The returning Snake River sockeye, remnants of the first population listed as endangered on the Columbia system 17 years ago, were all likely produced by a “duplicate broodstock” hatchery program in central Idaho that is trying to keep the genetic lineage of wild Snake River sockeye alive.

The fish topping Lower Granite traveled from the ocean over eight dams and 450 river miles to get by the fourth of four hydroelectric dams on the lower Snake.

That marathon run and the higher numbers demonstrate that the fish, despite their small numbers, “haven’t lost the long-standing traits that this population has deployed to survive for the last 10,000 years,” said Paul Kline, assistant fisheries bureau chief for the Idaho Department of Fish and Game.

The good sockeye news follows relatively good returns of spring chinook to the Columbia and good early indications on steelhead.

Ocean conditions have improved, including more nutrient-rich upwelling. Sockeye hatcheries on the Snake and the Columbia have significantly increased their smolt production, with releases nearly quadrupling in the past three years on the Snake.

And – most politically sensitive – a federal judge ordered federal agencies to boost springtime spills over key hydropower dams when the fish that are returning today were migrating to the ocean as juveniles.

A new report from the Columbia Basin Fish Passage Center credits the spike to court-ordered spills, better river flow and higher hatchery releases.

Michele DeHart, the Portland-based center’s manager, said her analysis indicates survival of juvenile sockeye headed to the ocean in 2006 and 2007 improved significantly after U.S. District Court Judge James Redden ordered more spill in late 2005, speeding the fish’s trip to the ocean. “The fish are telling us something as to what set of conditions works for them,” DeHart said.