The Idaho Department of Fish and Game is forming a working group this month to study why so few sockeye salmon returned to Idaho this year. That’s after the run of sockeye from the Pacific ocean to central Idaho, forecast to be about 800, was only 27 fish.
The bottom line here is, among other things, that the fish have a dam problem. More on that below.
Idaho sockeye have been on life support for decades. These salmon historically spawned by the tens of thousands in streams and lakes near the headwaters of the Salmon River.
In 1992, only one sockeye, a single male that was soon called “Lonesome Larry,” returned to Redfish Lake near Stanley. That was less than a year after Idaho sockeye were declared endangered under the federal Endangered Species Act.
In the 1990s, only 23 sockeye returned to Redfish Lake. In two of the years no sockeye returned at all. Thanks to the endangered listing and actions it made possible, in the last decade sockeye returns have averaged over 550 fish per year.
Efforts to save sockeye have followed two parallel paths. One has used hatcheries to rear sockeye to a size able to migrate to the ocean. These small smolts, as they are called, are then released into the Salmon River. The other path has reared sockeye in hatcheries to adulthood before releasing them to spawn in central Idaho lakes and streams.
Wild smolts, spawned directly into stream and lake gravels in Idaho, have the best record for surviving to return to Idaho. Hatchery smolts return at a much lower rate, but many more can be raised and released. The combination has so far been able to maintain about 95 percent of the genetic diversity of original wild Idaho sockeye stocks.
Salmon that hatch from eggs spawned in Idaho grow to only 3 to 7 inches long before drifting downriver to the Pacific Ocean. There they feed and grow for one to three years before returning as mature adults to repeat the cycle.
The trip, 900 river miles each way, is full of hazards. The smolts have to find their way past eight dams and through their eight reservoirs, four each on the Snake and Columbia Rivers. Along the way, predators from gulls and cormorants to native northern pikeminnows and introduced walleye and bass feast on unfortunate smolts.
The open ocean has its predators, too, including sport and commercial fishermen. Awaiting the returning sockeye in the Columbia River are sea lions. From the river’s mouth to the base of Bonneville Dam, several thousand sea lions feed on migrating salmon.
It’s the dams, rather than predators, that are hardest on salmon.
These fish evolved to move up and down free-flowing streams. Reservoirs are warmer, sometimes very much warmer, and often have almost no current at all.
For smolts to find their way from the inlet to the outlet of relatively stagnant reservoirs, over and over, is unnatural for them and not all of them succeed. The same is true for adult sockeye making the reverse trip.
In 2015, hot weather and low stream flow combined in the lower Snake River reservoirs to raise water temperatures to lethal levels. Well over 80 percent of endangered adult sockeye bound for Idaho died in that August heat wave.
Migrating salmon have been blocked by four dams on the Klamath River in California for decades. The dams produce power but do not provide irrigation water or flood control.
Last week, PacifiCorp, the operator of the dams, agreed to a $495 million plan proposed by the nonprofit Klamath River Renewal Corporation to remove the dams. While 1,720 dams have been removed from streams in the U.S. over just the last eight years, if it proceeds the Klamath River project would be by far the largest dam removal.
Legal actions by landowners along the river and others will likely delay any dam dismantling on the Klamath for years yet. PacifiCorp was happy to sign the agreement because the dams are aging and generate relatively little power for the company.
Could such a fate await the lower Snake River dams? The odds are against it. However, as those dams age, too, the economics of replacing them versus removing them will come into much sharper focus.
The problem is whether the distant relatives of Lonesome Larry will be extinct before that happens. I, for one, hope not.
Dave Finkelnburg is a long-time Idahoan, a former newspaper journalist, and is currently semi-retired from an engineering career.