Cowlitz River Coho return sets record

A little after 8 a.m. at the Cowlitz River Salmon Hatchery, about 800 coho idle in a narrow concrete channel impatiently leaping at the stainless steel grate barring their journey upriver.

“It’s kind of slow up here right now. A little while ago we had 2,500 or 3,000 fish per day,” said Hatchery Coordinator Jamie Murphy.

Although there are still several months remaining before the last fish returns, officials are already calling this a historic year for hatchery coho salmon returns.

Mark LaRiviere, senior fishery biologist for Tacoma Power, said “this year we broke an all-time record.”

As of Nov. 17, officials with Tacoma Power saw a record 87,054 adult coho salmon return to the Cowlitz Salmon Hatchery, topping the 2002-03 record of 85,632.

The 2014-15 run doesn’t end until March, but biologists at Tacoma Power predict the count to top 95,000 adults.

During the salmon runs, Murphy and three technicians spend hours processing migratory fish though what looks like a much wetter version of a postal sorting room.

The salmon are lifted out of the fish ladder, given a sedative electric jolt and slid onto a table. Workers then scan for electronic tags, separate wild fish from hatchery-raised fish and toss them snout first down various tubes leading to their respective fates as hatchery broodstock, foodbank donations or a truck ride past the dams and into the upper river basin.

This year’s return is encouraging because only about 19,600 coho came back in 2013 and 14,100 coho returned in 2012.

In 2010, with the goal of producing heartier and healthier fish, the hatchery underwent a $35 million overhaul. But the swing from 48,000 coho in 2011 to about 14,100 in 2012 left officials scratching their heads.

“We were like, ‘Wow, maybe we did something wrong,'” Murphy said. “Then we saw a ton come back this year and were like well, maybe we did something right.”

It’s not entirely clear why so few returned those years, but Tacoma Power officials attribute this year’s high numbers to strong survival of hatchery-origin coho moving out of the river systems, good production in the upper Cowlitz Basin and good ocean conditions.

“It means a lot of fish are out there to harvest,” said LaRiviere.

Some of the fish returning to the hatchery have a small wire in their snouts, which was inserted when they were smolts. Fisheries biologists scan the salmon after they are caught to give researchers a clearer picture of how the fish are migrating.

The Cowlitz River salmon are usually found along the Canadian coastline and the Aleutian Islands of Alaska, according to Murphy.

“They tag them because they want to know where they’re going and how many are caught to see how many are turning into adults and could possibly return back to river,” he said.

Across the Northwest, coho are returning to tributaries in record numbers. State wildlife officials originally predicted about 638,000 fish would make it to the mouth of the Columbia River, but now it seems close to a million will return.

Murphy said the numbers swing every year, so whether they'll see such a strong return to the Cowlitz is far from certain.

“It’s impossible to know what’s going to return from one year to the year,” he said.