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Harvest Managers Juggling Fish Runs
with Impact Limits

by Barry Espenson
Columbia Basin Bulletin - April 25, 2003

The 2003 upriver spring chinook salmon run forecast keeps rising, staying just ahead harvest impact limits that threaten to send home sport fishers who enjoy plying the lower reaches of the mainstem Columbia River.

At a joint Oregon-Washington sport fishing hearing Tuesday, anglers heard both glass-half-full and glass-half-empty musings. Washington's Bill Tweit reminded all that the number one task was to assure that harvest impacts stay within prescribed limits that are intended to protect particular stocks. He felt sport fishers might be uncomfortably close to those limits after completion of a Wednesday-Saturday fishery approved Tuesday for the area from the McNary Dam to Bonneville Dam and from the Interstate 5 bridge at Portland to the river mouth. The stretch from Bonneville to the I-5 bridge remains closed.

"We're very, very nervous about further fishing" after Saturday, said Tweit, the Washington Department of Fish and Wildlife director's representative at the hearing. Sport anglers on those lower Columbia River reaches are limited to a 1.11 percent impact on the "upriver" spring chinook run -- fish returning to hatcheries spawning grounds above Bonneville Dam. The run includes wild Upper Columbia and Snake river stocks that are listed as endangered and threatened, respectively, under the Endangered Species Act.

Tweit said that anglers should be put on notice that fishing would end Saturday unless the numbers on the ongoing upriver spring chinook run rise dramatically.

Oregon's Steve King would not go that far, saying only that a "major decision" would be necessary next week unless the run forecasts continued to improve. King was the Oregon Department of Fish and Wildlife director's representative at the hearing. The states plan a Monday afternoon hearing to digest new run data, and decide what, if any, mainstem fishing would be allowed below Bonneville. The pools between Bonneville and McNary are scheduled to remain open until May 15.

It was expected that the lower river fishery would run as late as May 15. But early fishing pressure was concentrated in the area near Bonneville and exacted a heavy toll on the upriver fish. On April 1 the season was adjusted from seven to four days per week and area from Portland to Bonneville Dam was closed.

The preseason expectation was that 145,400 upriver spring chinook adults would return to the Columbia. Last week the run forecast was adjusted upward to an estimate that 174,000 adult upriver chinook would return. On Monday, state, tribal and federal fisheries officials pushed that estimate up again -- to 193,000. With each forecast increase, the number of fish represented by that 1.11 increased.

The ODFW's Patrick Frazier thinks the run forecast could still grow.

"193,000 may be conservative," Frazier said. He feels that the 4-year-old component of the run may just be hitting its stride. For the most part, 5-year-old fish have dominated both commercial and sport catches of upriver fish through much of the season. But 4-year-old fish have become much more evident in recent catches.

An example is in "select area" commercial fisheries that began last week near the river mouth. An initial two nights of fishing witnessed an unusually high incidence of upriver fish in the nets -- nearly as many as through nearly six weeks of fishing last year and triple the 1999-2001 season average. The select area fishery is conducted two to three nights per week.

The select areas are sites where young hatchery spring chinook were released from rearing pens and are now returning as adults. The areas are tucked away off the mainstem where the migrating upriver fish are rarely found. Frazier thinks it may just be a numbers game.

"This fishery is an indication of whether fish are there. And fish are there," Frazier said of the high incidence of upriver fish. The 5-year-old upriver fish returned to the river earlier than expected, but the number of 4-year-olds from many upriver tributaries may just be surging in now.

Frazier said he believes the unanticipated high upriver encounter rate at the select areas may be because of "a new influx of upriver fish," some of which followed the select area hatchery fish home.

The overall impact limit of 2 percent for non-tribal fisheries is split three ways. The sport fishers get a 1.11 percent impact below McNary Dam and commercial fishers get .59 percent. The remaining .30 is split between the sport fisheries above McNary and the select areas with the expectation that some impacts would remain as a management buffer.

The limit will be pushed by this weekend unless the chinook run balloons. Early mainstem commercial gill netting shot the commercial fishers past their mainstem impact limit. Their catch calculates to an 0.67 percent impact, well over their limit of .59.

The sport fishery impact below McNary is expected to be at 0.88 percent after Saturday and the overall impact though Saturday for non-tribal fisheries is expected to be 1.73 percent. That doesn't count the select area impact, which would tack on an estimated .16 percent impact and leave only .23 for the buffer and above McNary fisheries.

"We're obviously at the point where we've used up a lot of the slack in the system," Tweit said. He pointed out that, with select area impacts added on, the so called "buffer" is already eroded by one-third. The buffer is intended to assure that the overall limit won't be broached.

"And our intent was not to get into that buffer," Tweit said. He said the states must now manage to stay under the overall non-tribal impact limit, instead of trying to assure that the sport fishery, for example, gets its full allotment.

Tweit said it was time to begin "the process of correcting for management errors and overages" that resulted when the commercial fisheries used up more than their share.

"We need to be straight forward about that," he said.

The spring chinook run continues to progress well with counts at Bonneville swelling a bit this week. The high count to-date has been nearly 8,000 on April 15. But the counts fell off drastically during the next four days as spill for juvenile salmon passage was ratcheted up at Bonneville, from 95,000 cubic feet per second to more than 140 kcfs. The counts were 4,800, 2,100, 2,800 and 2,400 April 16-19.

Frazier said that when spill was dropped, as part of a testing cycle, to around 100 kcfs, the counts climbed Sunday and Monday to 5,200 and 5,400 fish.

"It's no fluke, in my opinion, that your highest count days were when spill was around 100," Frazier said. He interpreted a jump in the count to Tuesday 6,400 -- a high spill day -- optimistically rather than as a deviation from the high spill/low count pattern. He and others are hoping it means that the run is still surging toward a peak.

The overall count has risen to 107,842 through Tuesday at Bonneville Dam. More than 17,000 adult hatchery chinook had been harvested by sport and commercial fishers between the mouth and McNary Dam through Saturday. Another 13,000 chinook were caught and released because they did not have an adipose fin clip.

It has been a popular sport fishery. An estimated 133,200 anglers trips had been logged through Saturday.

Frazier told the sport hearing that the fishing pressure is shifting, to the Willamette, Wind and other lower river tributaries.

"The Willamette is dragging a lot of the effort away from the Columbia River," Frazier said. Fishing catch rates have increased dramatically in the lower Willamette River as April has progressed.

The chinook salmon have just begun streaming into Idaho, where a sport season opened on the lower Clearwater April 12 and will open April 26 on the Little Salmon and Lower Salmon rivers.

The salmon count through Tuesday at Lower Granite Dam in southeast Washington was 13,863. Daily counts jumped this past week, ranging from 1,043 to 4,798. Lower Granite is the eighth and final dam the salmon must pass before reaching Idaho.

The count through Tuesday at Priest Rapids Dam on the mid-Columbia was 5,252 adult salmon.

Related Sites:

Barry Espenson
Harvest Managers Juggling Fish Runs with Impact Limits
Columbia Basin Bulletin, April 25, 2003

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