[3] Feds Slam Latest Fish Passage Center Fish Study
Federal scientists found plenty to complain about in the latest report by the Fish Passage Center, which reviewed 10 years' worth of data and analyzed PIT-tags from hundreds of thousands of hatchery salmon in the Columbia and Snake basins.
The 10-year retrospective report has been handed over for final review to the panel of independent scientists who work for NOAA Fisheries and the Northwest Power and Conservation Council before the council approves any new funding for the FPC's $1.3-million annual project known as CSS [Comparative Survival Study].
Critics both in and out of the government have complained about different aspects of the study since it began, saying its conclusions have consistently downplayed the benefits of transporting most stocks of Snake River salmon and steelhead past federal dams.
The latest comments from federal scientists and BPA consultants reiterated those earlier complaints, along with newer concerns and more evidence that the PIT-tagged return rates are considerably less than those of the unmarked population.
The feds also took issue with the report's conclusion that by using flows to reduce the travel time of certain stocks, such as steelhead, through the hydro system, mortality would go down by 5.6 percent. The feds said the report's analysis that correlates survival with water particle travel time "is a classic example of a 'spurious correlation.'"
The FPC response said that NMFS had "mischaracterized the work," and that fish travel time is a function of other variables as well as water particle travel time, which include average percent spill and Julian day.
The NMFS scientists said the latest report left out the analysis of fish return rates from the FPC's 2005 report, which the Independent Scientific Advisory Board [ISAB] had recommended they include.
"The absence of these analyses," said the feds, "begs the question as to why, and implies the analyses may have weakened the report's statements about wild fish SARs [smolt-to-adult return rates]."
The latest CSS report says wild chinook and steelhead have not benefited from being barged, but the NMFS reviewers questioned the results, noting that when they analyzed the CSS data, they found unmarked hatchery and wild fish returned at higher rates than the PIT-tagged fish--for both hatchery and wild fish.
In their 2005 comments, NMFS scientists said in five of the 10 years studied, the point estimate of annual SARs for transported wild chinook was higher than for inriver migrants.
Unnamed BPA consultants also weighed in on the latest CSS report. They said it didn't include enough information for them to replicate the findings by using accepted modeling procedures, which made them conclude the report didn't "demonstrate the scientific rigor and support to authoritatively guide hydrosystem management."
The consultants also said the CSS report's analysis of upstream/downstream stocks was invalid. It found that wild chinook SARs from the Snake were only about one-quarter of those from the John Day River in the lower Columbia. However, BPA said the analysis omitted natural mortality factors that should occur between upstream and downstream sites.
The feds also noted that a 2007 ISAB report advised against trying to measure absolute latent mortality, which is a large part of the FPC's analysis of upstream/downstream productivity. The ISAB said the focus should be on the total mortality of inriver migrants and transported fish.
Another point critics cited was the fact that upstream hatchery stocks sometimes had better SARs than the downstream hatchery fish from the Carson facility, one reason why NMFS reviewers felt that the data from hatchery fish really didn't provide information on how to best operate the hydro system for wild chinook.
The CSS Oversight Committee acknowledged that Snake hatchery fish were helped more by transportation and showed relatively lower levels of differential mortality than wild stocks, but annual SARs between wild and hatchery stocks were highly correlated.
"In view of this high correlation," said the committee, "continuing the CSS time series of hatchery SARs will be important to augment wild chinook SAR information following future years of low escapements, in addition to providing valuable management information for the specific hatcheries."
But NMFS said the same information could be gleaned from much smaller numbers of PIT-tagged fish or simply by comparing adult returns of clipped (hatchery) to unclipped fish. Their earlier analysis found that PIT-tagged wild fish returns were only about 60 percent of untagged fish, which made them question the CSS results claiming that Snake River wild chinook returns aren't meeting the 2-percent return-rate goals for the region.
The latest CSS report is now being reviewed by two panels associated with the Power Council, the ISAB, which reports on general issues having to do with salmon recovery science, and the ISRP [Independent Scientific Review Panel], which judges the scientific merit of BPA fish and wildlife proposals. Council staffer Erik Merrill said their reviews should by completed by Oct. 19 and will be used by council members to help determine if the CSS work should be funded in the future. -B. R.
The following links were mentioned in this story:
Comparative Survival Study, 8/31/07
NW Fishletter 212, Mar. 29, 2006
NW Fishletter 229, April 16, 2007
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