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Catch Rate Up; Return Numbers Consistent with Late Run Time by Barry Espenson Columbia Basin Bulletin - April 16, 2004

Accelerating recreational catch rates on the lower Columbia River mean fish are present in relatively ample numbers, but upriver spring chinook salmon counts at Bonneville Dam continue to lag behind those that produced the bountiful returns of recent years.

After a slow start to the season, fishing has picked up in the mainstem waters below Bonneville. Anglers caught 11,642 chinook during the first 11 days of April and kept 9,065 of those fish. The sport fishers can keep hatchery salmon with an adipose fin-clipped, as well as steelhead and shad, but must released unmarked salmon.

That April 1-11 harvest was accumulated during 51,858 angler trips during which the catch rate was 0.26 salmon per boat angler. During 54,000 trips in February and March, fishers averaged a meager one salmon for every 12 boat anglers.

The ever-increasing catch rate in recent days forced Oregon and Washington department of fish and wildlife officials to rein in the sport fishery.

Beginning April 22, the area between the Interstate 5 bridge at Portland and Bonneville Dam will be closed on Thursdays, Fridays and Saturdays. The area has been open seven days per week from the dam to the mouth of the Columbia.

The modification is necessary, officials say, to keep the fishery to stay within "impact" guidelines and continue the fishery as long as possible. A pre-season fishery plan calls for modifications to the area from I-5 to Bonneville Dam as the first step to reducing the impacts to upriver chinook listed under the Endangered Species Act. The wild Snake River component of the run is listed as threatened and the wild Upper Columbia spring chinook endangered.

A total impact of 2 percent on the upriver fish is allowed for mainstem non-Indian fisheries with sport anglers apportioned a 1.2 percent share and commercial anglers getting 0.8 percent.

The sport fishery from Bonneville to the mouth gets two-thirds, 0.8 percent, of the sport share. Through April 11, the lower river sport fishery catch represented 37.6 percent of its impact allotment. It the sport fishers catch 11,000 fish from April 12-18 as is projected, they will have absorbed 67.5 percent of their impacts.

The closure between Portland and Bonneville is intended to reduce the catch of those upriver fish. In the mainstem below Portland, there is a strong mix of upriver salmon and fish bound for the Willamette, Cowlitz, Lewis and other rivers that pour into the lower Columbia. The migrating fish caught between I-5 and Bonneville were more than 80 percent upriver fish bound for hatcheries and spawning grounds above Bonneville, which means the upriver "impacts" mount quickly.

The catch rates this past week have been particularly high in the waters just below Bonneville -- about double the overall catch rate. During the April 1-11 period about one-quarter of the angler trips were in the I-5-to-Bonneville zone but more than one third of the catch was there.

"That has been the hot spot. Within the past week (fishing effort) was really focused on the upriver part were there is the highest impact and the highest catch rates," said Kathryn Kostow of the ODFW.

The impact rate calculations for harvest thus far are based on a preseason forecast that 360,700 adult upriver chinook salmon would return to the mouth of the Columbia on their spawning migration. It is estimated that 109,400 Willamette River origin adults will also return. If that upriver run materializes it would be the second largest on record since count began in 1938 at the newly christened Bonneville Dam.

But through Wednesday, only 14,125 adult chinook had been counted at Bonneville, despite surges that produced a 4,767 count on Tuesday and 3,035 on Wednesday. ODFW and WDFW staff said the "run still appears to be consistent with a late run time."

If that run projection is reduced by some measure, it could mean that the impacts accumulated to-date are near or even past the impact limits. Non-tribal commercial fisheries in the lower river have already incurred two-thirds of their impact allocation based on preseason run forecast with a total "kept catch" estimated to be 15,475 (13,546 in the mainstem and 1,929 at select area fisheries near the river mouth). Of that total, 5,563 were upriver chinook. The total non-tribal harvest to date is 27,202.

The Bonneville adult salmon count was 72,231 through April 14, 2003 when the "run timing" was extremely early, driven by a dominant 5-year-old age class. The 2003 run totaled 208,900 adults. The older fish on average return from the ocean earlier in the season as compared to the 4-year-old age class. The 4-year-olds are expected to make up as much as 95 percent of this year's run.

The count through April 14, 2002, was only 24,393 -- the vanguard of a 295,100-fish run that still holds the distinction of being the second-largest return since 1938. The record 2001 run of 416,500 upriver spring chinook adults to the mouth of the river was more than one-third complete by April 14 with a cumulative count at Bonneville of 150,536.

The recent run of strong upriver spring chinook returns began with a 178,600-fish count (37,249 through April 14). The upriver stock had been relatively depressed prior to 2000, including a 1999 return of only 38,700 upriver adults (2,554 count at Bonneville through April 14) to the river mouth.

The impact limits are imposed via a management agreement between the states, including Idaho, and four lower Columbia treaty tribes and is endorsed by NOAA Fisheries, one of the federal government's ESA enforcers. The agreements are consistent with decisions made in U.S. v. Oregon process -- where the U.S. District Court retains jurisdiction on treaty fish rights issues.

"Those are things we don't want to violate" by allowing non-tribal fishers to breach impact limits, Kostow said. A portion of the allowable impacts are reserved as management "buffers" until there is more certainty about the actual size of the run. Meanwhile, the states want to allow sport and commercial fishers access to as many hatchery fish as possible.

"It's a real balancing act," Kostow said. The Technical Advisory Committee is scheduled to meet next week to decide if enough information is available to update the spring chinook run forecast. The committee composed of state, federal and tribal biologist was formed as a result of U.S. v Oregon.

On average, 50 percent of the upriver run has passed Bonneville by late April. But that midpoint will probably come later this year, Kostow said.

"We're finally getting to where we're getting some reasonable numbers" on which to base a revised forecast, she said of the surging counts at Bonneville. Some fisheries officials are, admittedly, getting nervous.

"Some of us (TAC members) expect it will not really be 360,000. Some are holding to that," Kostow said.

Related Pages:
Bonneville Dam Fish Counts Now Above 10-Year Average Barry Espenson, Columbia Basin Bulletin, 4/23/4