By Rusty Bentz
This is what we believe is wrong with the dam breaching concept. There were far more fish that returned in the first 15 years of the 21st century than ever did in the 20th century, fully 25 years after construction of the last dam on the lower Snake River. That is the case for both steelhead and spring and summer chinook. The total steelhead run over Bonneville Dam for the first 10 years following dam construction when Bonneville Dam was the only dam blocking access to the Snake River for salmonoids, was 1,274,530 steelhead. For the first 10 years of the 21st century the total was 4,014,400 steelhead. A 315% increase. For spring chinook, the numbers are 618,952 vs 1,634,639, a 264% increase.
This proves we can HAVE FISH AND DAMS. Sockeye salmon were poisoned out and blocked from returning to their spawning grounds in the mid- 20th century. Fall chinook have rebounded from a low of less than 200 returning over Lower Granite Dam to a high of over 50,000. Coho salmon which did not return to the Snake River until the 21st century and are now returning in high enough numbers to have a general fishing season.
We have lost 80% of our fall chinook spawning grounds, 70+% of spring and summer chinook spawning grounds, 65% of our steelhead spawning grounds, to dams with no fish ladders (think Grand Coulee Dam and the Hells Canyon Dam). Fish hatcheries were constructed to make up for this loss of spawning habitat. These hatcheries have done a good job of producing juvenile salmonoids as evidenced by the high number of adults returning in the 21st century.
The other essential element to high adult returns is barging and smolt collection facilities. In 2000, 5,039,620 steelhead smolts were collected and 95.1% barged, the next year, 633,073 adult steelhead returned, the highest number ever recorded. 2/3 of those fish were 1-ocean fish. 2005 was the last year that 5 million+ fish were collected in the 21st century, then it drops to 2 million+ to just 275,073 collected in 2021 and only 37.5% were barged. WE ARE HAVING A DISASTRUS RETURN THIS YEAR in spite of having the best ocean conditions in 2021 in 24 years.
In the final analysis, how we should measure our success is by adult returns. However, how many fish we get back is related to the number that starts the journey downstream. It is obvious by the number collected at Lower Granite Dam is declining rapidly. As noted in previous Columbia Basin Bulletins articles smolt detection is a problem when we spill. This inaccurate count combined with no method to account for the difference in adult harvest in good years versus bad years makes SARs a poor measure.
Steelhead counts started declining in 2016 which corresponds with low barging numbers in 2015. Very low runoff insured that travel times for smolts left in the river were long. Low hot water behind the 4 lower Columbia River dams kept the sockeye salmon from going over the fish ladders and they died by the thousands.
After a lawsuit against NOAA Judge Simon ordered spill for 2016. The steelhead return for 2017 dropped to 117,878 adults. The lowest number since 1979. Judge Simon ordered even more spill for 2017 and adult returns dropped even lower to 102,920 adults. High spill cause two problems, the major one is gas bubble disease and the second is the inability to trap smolts at Lower Granite Dam. Gas bubble disease is a well-known phenomenon dating back to the 1960’s and a flip lid was put on John Day Dam to try to solve the problem. We know what the problem is and we know how to solve it. Run the water thru the turbines which produces power as well as solving the dissolved gas problem. With spill becoming the preferred alternative to get smolts downstream that has guaranteed that we are going to have poor returns as evidenced by the 2021 low return of 71,980 adult steelhead. This low return is in spite of having 3 years of La Nina which produced the best ocean conditions in 2021 in the past 24 years.
For us to return to 600,000+ adult returns enjoyed in the first decade of the 21st century we need to up hatchery production so we can capture the 5 million+ smolts at Lower Granite Dam instead of the 3-year average of 1,188,442 smolts collected 2019-2021 and we need to barge a high number of those smolts. Barging solves 2 major problems, the problem associated with gas trauma disease and predation problems caused by other fish and birds. There has been a number of improvements in barging since the start of barging in 1977. Modern barging gets the smolts below all 8 dams with a 98.5% survival.
There are 2 articles published recently in the CBB that detail the advantage of letting straying hatchery steelhead and salmon spawn in the wild with wild fish. The 10- year average for wild steelhead in the first decade on the 21st century is 117,000 fish which is over 92% of the 127,000 over Bonneville Dam 1938-1947. Wild steelhead are doing great despite losing 65% of their spawning grounds.
In conclusion without barging and smolt collection facilities provided by the dams we are guaranteed to have fewer returning salmonoid adults.
Rusty Bentz is an Idaho outfitter and guide for steelhead and salmon, based in Lewiston.