Spring Chinook Fishing Hot; New Tangle Net Data Could Boost Commercial Catch

Columbia Basin Bulletin

April 4, 2008  

Beleaguered non-tribal commercial fishers on the lower Columbia River received some good news this week with the assessment that the so-called "tangle" nets used in spring chinook salmon harvests in recent years cause less mortality than previously believed.

The bottom line is that gill-netters, who've seen their share of harvestable fish shrink, should be able to catch and sell more fish.

Those tangle nets were deployed for the first time this year on Tuesday, targeting what appears to be a budding upriver spring chinook run. Sport catches on the Columbia mainstem ballooned over the past two weeks as the salmon return begins to build strength. The run normal begins with a trickle in March and peaks, in terms of Bonneville Dam counts, in late April.

The states of Oregon and Washington , which jointly regulate Columbia mainstem sport and commercial fisheries, began evaluating the use of smaller-mesh tangle nets in 2001 as a means of reducing fishing impacts on wild, unmarked salmon. Several salmon, and steelhead, stocks are listed under the Endangered Species Act.

The tangle nets, with 4 ¼-inch mesh, have proven to cause less damage to captured fish than larger 8- or 9-inch nets that "gill" and suffocate the salmon. That allows a selective fishery in which unmarked, protected fish can be released back into the river to continue their spawning journey.

A 2003 analysis of data collected from 2001-2003 indicated that immediate and delayed mortality for spring chinook and steelhead released from the tangle nets was 18.5 percent as compared to 40 percent for spring chinook and 30 percent for steelhead released from large mesh gill-nets.

A more comprehensive analysis completed late last year showed a different result -- a 14.7 percent mortality rate for spring chinook caught and released from the tangle nets. The newer analysis utilized more releases of tagged control fish, and more recoveries of tagged treatment fish than were available in the preliminary 2003 analysis. The research compared the survival of tagged fish caught in nets and released in the lower river to that of fish that were captured in a trap at Bonneville, tagged and released.

Columbia mainstem fisheries are managed to assure no more than a 2 percent non-tribal impact on the upriver spring chinook salmon run, which includes listed Snake River and Upper Columbia stocks. This year the recreational fishery was allocated approximately 61 percent of those impacts and the commercial fleet 39 percent. The preseason forecast is for an upriver spring chinook of 269,300 adults to the mouth of the Columbia .

Those impacts build as more unmarked chinook are caught and released. It is estimated that 10 percent of the chinook caught and released from anglers' hooks die.

The Technical Advisory Committee reviewed the new analysis and this week recommended that the Columbia River Compact use the 14.7 percent tangle net mortality rate in managing this year's fisheries. The Compact agreed. TAC is made up of federal, state and tribal fisheries officials. The Compact, which sets mainstem fisheries, is made up of representatives of the Oregon and Washington department of fish and wildlife directors.

The lower mortality rate means that the commercial fleet, when using tangle nets, can catch more marked hatchery fish for every increment of ESA impact, i.e. nearly three fewer mortalities for every 100 unmarked fish caught than with the large mesh nets.

State monitors on Tuesday observed 83 "drifts" in which 120 upriver chinook were caught that were marked at the hatchery with an adipose fin clip. The observed catch, a sampling of the fleets' overall activity, included 32 unclipped fish that had to be released -- about 20 percent of the catch.

State official have yet to estimate the total catch during the 11-hour commercial fishery in the Columbia above Hayden Island at Portland and Bonneville Dam. But the ODFW's John North said he expected it to be about 500 to 700 fish.

"I think the effort was real low," perhaps as few as 30 boats, North said. With the run in its early stages some commercial fishers possibly decided to bide their time. All commercial chinook fishing this spring will be confined to the area between Bonneville and Hayden Island , which is located a few miles upstream of the Willamette River 's confluence with the Columbia . The intent is to avoid the netting of Willamette River spring chinook, which are expected to return in low numbers this year.

The majority of the fleet is based near the river mouth, about 100 river miles from Portland . So it is a costly venture to chug upstream given record high fuel prices.

Still, with spring chinook fetching in the range of $10 per pound they are an inviting target. The vast majority of the returning fish are expected to be younger adults, 4-year-olds. North said the catch would probably average about 15 pounds per fish.

The boats monitored Tuesday averaged two chinook per drift. The drifts are limited to 45 minutes from the moment the first mesh hits the water until the last is pulled out so the fishers can probably make about one drift per hour at most, North said. The "soak time" is limited to assure that fish are not enmeshed for long periods.

The 83 drifts observed netted only two steelhead, which must be released gill-netters. Winter steelhead stocks are also ESA listed with the non-tribal sport and commercial fisheries limited to a 2 percent impact. Anglers can keep clipped steelhead but must release unmarked fish.

"I'd classify it as a very clean fishery," North said of the management goals of avoiding impact to listed fish while allowing access to hatchery fish. The tangle nets can have the disadvantage of increasing the handle -- the netting -- of the smaller sized steelhead.

The prospect of a strong upriver spring chinook run, and a limited window for fishing below Hayden Island , brought sport boats out in high numbers this past weekend. There were 1,542 salmonid boats and 501 Oregon and 254 Washington salmonid bank anglers counted on Saturday's aerial survey of the lower river.

"This fishery is definitely up and running, with catch rates running as high a chinook per boat in some areas" said Joe Hymer, a fish biologist for the Washington Department of Fish and Wildlife. "We haven't seen fishing this good in a number of years."

In all, angler turnout was nearly twice as high as in the past two years on the same date.

A big part of the attraction is that catch rates for March were higher than in any year since 2002. Through March 31, anglers caught 4,400 chinook in the lower river, compared to 1,100 last year and 1,900 in 2006. Overall from Buoy 10 to Bonneville Dam, fisheries managers estimate there were 36,124 angler trips made from March 16-31.

In a creel check conducted during the last full week of the month, 4,431 anglers reported catching 726 adult chinook and 10 steelhead below the dam. For boat anglers, that translated to one adult chinook kept or released for every 5.4 rods, compared to 12.5 rods in 2007, 5.6 rods in 2006, 17.1 rods in 2005, 6.4 rods in 2004, 7.1 rods in 2003 and 4.7 rods in 2002.

Bank anglers fishing below Bonneville Dam have been averaging one adult chinook for every 28.7 rods, about the same as in recent years.

"The preseason forecast called for a strong return of upriver chinook, and that's just what we're seeing on the fishing grounds," Hymer said. He noted that 88.5 percent of the fish sampled were identified as upriver stock.

As in past years, anglers may retain only hatchery chinook and steelhead, identified by a clipped adipose fin. All wild chinook and steelhead with an intact adipose fin must be released.

Hymer reminded anglers that Friday is the last day to fish for spring chinook in waters downstream from the west power line towers on Hayden Island . From the west power lines upstream to Bonneville Dam, fishing will continue six days per week – closing from one hour after official sunset Mondays to one hour before official sunrise Wednesdays – through April 30. The limit is one hatchery chinook per day. The closures are intended to avoid conflicts with commercial fisheries, which would be scheduled during that time period each week.

Above Bonneville Dam, chinook fishing was slow through the end of March. But that is expected to change by April 10, if not before, Hymer said.

"Starting April 10, spills are planned at Bonneville Dam to help move juvenile salmon downriver," Hymer said. "Those spills should also spur more adult salmon to move upstream, and improve catch rates for bank anglers just below the dam."

Chinook fishing is currently open seven days per week on the Columbia River from Bonneville Dam upstream to McNary Dam

Anglers were likely motivated by the fact that this past weekend is the only weekend this spring that the area downstream of Hayden Island will be open to fishing for the rest of the season. The area was closed March 16 to chinook retention, then reopened only for the March 24-April 4 period. The restrictions are also intended to reduce pressure on the Willamette spring chinook run.

Salmonid anglers were the most successful in the Portland to Longview area where boat anglers averaged 0.54 spring chinook caught per boat. In Troutdale, boat anglers averaged 0.32 spring chinook caught per boat, while salmonid anglers in the gorge averaged 0.27 spring chinook caught per boat. In the estuary boat anglers averaged 0.25 spring chinook caught per boat. Bank angling has been slow for spring chinook throughout the lower Columbia River , according to the agencies.

The number of chinook climbing Bonneville's fish ladders seems to be on the rise. There were 20 counted Sunday, 21 on Monday and 26 on Tuesday, the three highest daily counts so far this year. The total count to-date is 199.

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