[4] The Case Of The Vanishing Fall Chinook
Some adult fall chinook on their way back to Idaho seem to be disappearing, leading a coalition of Columbia River users involved with the BiOp to call on NOAA Fisheries to investigate "some new and alarming statistics for which there are currently no answers."
In written comments to NOAA Fisheries, Northwest River Partners' executive director Terry Flores said that data presented in a lengthy appendix to the BiOp's supplemental comprehensive analysis (on p. 602 of the 820-page document) "establishes that adults are encountering difficulties in migrating through Zone 6 and the lower Snake River reaches."
Zone 6 is the area above Bonneville Dam where tribal fisheries occur every year.
The NWRP letter said that data included in the draft BiOp shows that in 2006, Snake River fall chinook and steelhead were reported to have incurred an unexplained mortality "higher than normal." They said the data also show, along with reported harvest, an additional 20 percent of unexplained mortality of Upper Columbia steelhead between Bonneville and McNary dams. They speculated that the loosely monitored A-run steelhead harvest might explain the discrepancy.
In any case, the group has recommended that NOAA Fisheries implement a new "Reasonable, Prudent Alternative" (RPA) in the final hydro BiOp that will investigate the issues "to ensure that appropriate actions are taken to mitigate this significant new source of mortality."
The group said the sharp drop in survival could come from "unaccounted for" harvest or increased spill, which, in some cases, has already been found to impede the adult spawning migration.
The BiOp data, drawn from PIT-tag survival information, show that 2005 and 2006 conversion rates (the percentage of fish that survive from dam to dam) for Snake fall chinook between Bonneville and Lower Granite dams dropped significantly--from about 95 percent (adjusted for harvest) in 2004 and earlier years to 72 percent in 2005 and 56 percent in 2006.
However, others familiar with the issue say the results may simply be "random noise." Results for 2007 are not quite ready.
It's doubtful that increased spill may be the culprit, since fall chinook numbers usually peak at Lower Granite in early September, after the spill season ends on Aug. 31.
Flores made it clear that her group supports the draft BiOp with its collaborative approach and its use of the best available science, but she told NW Fishletter that NOAA Fisheries needs to apply the same scientific and legal standards it has used in the hydro BiOp to the upcoming harvest BiOp that will gage impacts of future tribal and non-tribal harvests on ESA-listed stocks like Snake River fall chinook and B-run steelhead.
"But gains from hydro should not be lost on the harvest side," Flores said. However, that doesn't seem to be the way things are heading.
The nearly-finalized harvest agreement among parties to the U.S. v. Oregon process is likely to boost harvest rates of both those listed stocks when overall runs are healthy .
The NWRP letter also calls for the upcoming harvest BiOp to use the same biological analysis that supports the hydro BiOp, since the two are complimentary. For instance, the proposed boost in steelhead harvest is expected to be offset through "compensatory mitigation" developed in the hydro BiOp.
Columbia-Snake irrigators also had a bone to pick with NOAA Fisheries over hydro and harvest issues raised in recent days.
Darryll Olsen, principal consultant with the Columbia-Snake River Irrigators Association, said in his own comments to NOAA Fisheries, that the fish agency should not embed current harvest rates into the BiOp's environmental baseline because that requires "the hydrosystem management system to compensate directly for harvest impacts that are well beyond the scope of any hydro project operations."
Olsen called that a "critical defect" in the draft BiOp, but it's unlikely the agency will heed his criticism.
NOAA Fisheries has already been negotiating with lower Columbia tribes and Northwest states to actually boost harvest rates for fall chinook that would increase impacts on listed Snake fall chinook and B-run steelhead when Mother Nature provides bounteous runs. But when runs are poor, the proposal also calls for less harvest than allowed under the current regime.
In comments made public Jan. 10, the Columbia River Inter-Tribal Tribal Fish Commission included its proposal for future B-run steelhead harvest that has been negotiated through the U.S. v. Oregon process. When the upriver bright-run size (to river mouth) is expected to be greater than 200,000 fish, the treaty harvest rate will be pegged at 20 percent, up from the current 15 percent.
The CRITFC comments also say that NMFS has estimated the harvest-rate increase would reduce the overall survival of the B run by 2.9 percent.
But the tribes' own analysis claims that "relative to rebuilding, reductions in harvest rates at lower run-size abundances are more important than increases in harvest rate at higher run size where effective maximum population sizes are limited due to SAR [smolt-to-adult return rates] survival constraints."
The tribes want future harvest rates included in the new BiOp's baseline, but Olsen and his irrigators feel that including even current harvest rates in the new BiOp "masks the real impacts of the current harvest regimes, and the overall survival of fish through the mainstem hydro system."
"Given that allowing harvest of an endangered species is all but unheard of as part of an ESA recovery plan," the irrigators said, "further assessment is warranted of the recovery benefits that would accrue if NOAA Fisheries curtailed further harvest regimes."
They also said the new BiOp should spell out the biological benefits and costs of reducing harvest compared to other hydro-operation measures. -B. R.
The following links were mentioned in this story:
Supplemental Comprehensive Analysis, NOAA Fisheries, Oct 31, 2007
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