With the 2010 Snake River sockeye salmon return to Sawtooth Valley headed for a record, Idaho Department of Fish and Game biologists started this week passing fish through the adult trap on Redfish Fish Lake Creek to continue their spawning journey.
The strategy is a first in the history of Snake River Sockeye Salmon Captive Broodstock Program, which was started in 1991 to ward off extinction of the endangered fish species.
In past years officials have trapped all of the returning sockeye, or as many as possible, and trucked them to Eagle Hatchery near Boise for holding. There they are evaluated to determine which best fit the genetic needs of the broodstock program. Some are chosen and the rest are later hauled the 130 or so miles back up to Redfish Lake and released to spawn on their own.
"We're only looking to keep 100 of these returning anadromous fish to incorporate into our broodstock," Eagle Hatchery manager Dan Baker said. Already in hand at Eagle is a fairly complete representation of the available genetic material.
And the available holding space at Eagle is almost sure to fill up. Through Thursday a total of 701 adult sockeye had been trapped either at Redfish Lake Creek or nearby Sawtooth Hatchery on the Salmon River. The hatchery capacity is 1,000.
Who'd have thought that the broodstock program would have a capacity problem?
After all, between 1999 and 2007, a total of only 355 hatchery-produced adult, sockeye salmon (and no naturally produced fish) returned to the valley. And most of them appeared in 2000 (257).
But the 2008 return jumped to 650 and last year's return was a record – 883.
But the 2010 run is ahead of last year's pace when only 341 sockeye had been accounted for through Aug. 12.
A flood of sockeye, relatively speaking, washed the Sawtooth Valley recently. The daily capture totals from Aug. 4-10 have been 53, 51, 91, 61, 83, 63 and 68. Each is higher than last year's high daily count of 46.
The arrivals may well have peaked. The last five days' trapping totals have decreased. Still, 40 fish arrived Wednesday and 39 were trapped Thursday.
"We expect to hit capacity at some point," Baker said, so biologists began Wednesday releasing about one-quarter to one-third of the arrivals and will continue to do so through the end of the month. After that, with the spawning season soon to begin, all of the returning fish will be passed through to spawn in Redfish Lake.
"We're still getting information from those fish," Baker said. Genetic samples and information from tags are gathered from the fish before they are released from the trap.
Idaho Sen. Mike Crapo, NOAA Fisheries Deputy Regional Administrator Barry Thom and Hatcheries and Inland Fisheries Branch Chief Rob Jones, BPA Administrator Steven Wright and aides, and Idaho Fish and Game Commission Chairman Dr. Wayne Wright were on hand Wednesday celebrate this year's burgeoning sockeye return and witness the capture, processing and release of sockeye at the salmon trap on Redfish Lake Creek. BPA has funded the broodstock program and NOAA Fisheries is the agency responsible for protecting listing species and is also involved the program.
The great majority of the returning sockeye are the result of smolt releases at Sawtooth Hatchery or in Redfish Lake Creek. The smolts were reared at either Sawtooth or Oxbow Hatchery near Cascade Locks, Ore. All are marked with clipped fins or/and identification tags.
Of the 491 fish trapped through Aug. 8 this year, 100 were unmarked. That means they are the product of spawners returned to Redfish Lake, from "residual" sockeye that never made the trip to the ocean or from eyed-egg outplants at Pettitt and Alturas, two other lakes in the Stanley basin.
"We're getting good survival for these naturally produced fish," Baker said. Preliminary calculations indicate smolt-to-adult returns for fish produced by natural spawners are as high or higher than SARs of the released hatchery smolts.
A total of 2,126 sockeye had been counted through Wednesday at Lower Granite Dam on the lower Snake River. That's a record in the history of the dam, which was completed in 1975. From that point, the sockeye still have about 400 miles to swim up the Snake and Salmon rivers to Sawtooth Hatchery. The peak daily count this year was 162 on July 6. The counts have been declining every since with Wednesday's total being 7. Last year the season's total at Lower Granite was 1,219.
The Snake River stock was federally-listed as endangered in November 1991.
The broodstock program, a multi-agency and tribal effort started in May 1991, was initiated to protect population genetic structure and to prevent the further decline of Idaho sockeye salmon. The program also produces eggs and fish to reintroduce to the habitat to increase population numbers.