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2,000 Upper North Fork Lewis Smolts Die In Mishap

“Human error” was unfortunately to blame when a steady stream of dead and dying smolts began drifting past Dan Moir and his wife early last month.


They were fishing the North Fork Lewis just below Merwin Dam on June 1 when they noticed dozens upon dozens of the young fish float by their boat.

“They are kinda trying to wiggle, but I think they’re not going to make it,” Moir narrates in the 80-second video he took and shared with Northwest Sportsman magazine. “Some of them made it, but most of them, it looks like they’re dead.”

A tanker truck can be seen just upstream, and according to a report submitted by PacifiCorp to federal fishery overseers 11 days later, some 2,000 smolts died as a result of low oxygen levels in the vehicle’s holding tanks.

The rig was transporting 5,725 coho, spring Chinook and winter-run steelhead — part of an ongoing effort to reseed the upper North Fork — from the utility’s Floating Surface Collector at Swift Dam to a release site on the mainstem Lewis near Woodland.

According to a June 12 letter from PacifiCorp’s Mark Sturtevant, vice president of renewable resources, to National Marine Fisheries Service biologist Josh Ashline, the loss was attributed to oxygen volumes that weren’t adjusted by the driver as the tanker was being loaded with more fish.

Catching his mistake before leaving Swift, he checked on the fish twice en route. The first time they “looked fine,” according to the letter, but down the road at a weigh station pulloff, he “noticed that some of the fish had died and others were distressed.”

Once in cell phone service, he called a manager who advised him to drive to the Merwin Boat Ramp just below the dam, and there they “observed numerous fish mortalities and stressed fish” in the tank.

“(The manager) then directed the truck driver to release the fish into the river,” the report states.

Those were the smolts that the Moirs saw floating downstream.

A check of the rig’s oxygen and water aeration mechanism’s found it to be “functioning as designed.”

“It is something we feel terrible about and don’t want it to happen again,” said PacifiCorp spokesman Spencer Hall yesterday afternoon.

The report details proactive steps taken with drivers and loading protocols to prevent another mishap.

Hall describes it as the “only incident of this nature” since the utility began operating its $63 million surface collector on the uppermost of the three North Fork Lewis impoundments.

It’s part of a federal dam relicensing agreement to open up more than 100 miles of stream habitat in the watershed above Swift Reservoir.

Moir worried in the video that the dead and dying smolts had come from a hatchery release gone very wrong. While it’s likely that most of the fish’s parents did come from a production facility, these young fish were spawned in the wild.

All but 95 of the salmon and steelhead in the tanker truck that day were coho.

The truck driver and manager initially collected around 300 dead fish at the boat ramp, with PacifiCorp biologists recovering another 1,700 in the following days.

It’s primarily a potential setback for the utility’s bid to get a steady stream of 9,000 silvers back to the headwaters, according to a 2012 article in The Daily News that also noted the goal includes 2,000 springers and 1,500 winters.

In its 2018 annual report, PacifiCorp stated that last year it transported 7,060 adult late and early coho, 1,225 winter steelhead and 700 spring Chinook into Swift.

The utility also reported moving 55,336 smolts — 73 percent coho, 14 percent steelhead, 12 percent spring Chinook and 2 percent cutthroat trout — from the FSC to the lower Lewis last year.

Lewis springers have been identified as being among the most important feedstocks for struggling southern resident killer whales.

“While this event is extremely unfortunate, PacifiCorp is proud of the Lewis River Fish Passage Program and its continued success in operations and its contribution to establishing salmon and steelhead populations upstream of Swift Dam,” said Hall.

Editor’s note: The last name of Dan Moir was misspelled in the original version of this blog. Our apologies.