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Council's Science Board
See-Saws on Supplementation

by Bill Rudolph
NW Fishletter, June 13, 2003

Building and operating hatcheries to raise fish that are added to streams in order to boost wild runs in Columbia Basin has been one of the biggest and most expensive priorities of BPA's fish and wildlife program. Yet, this strategy, which has consumed about 30 percent of BPA's direct program funding since 1978 and has cost ratepayers more than $300 million, has never been tested to see if it actually works.

It's still an "experiment" with "overwhelming uncertainties," said the Independent Scientific Advisory Board [ISAB], in a full-blown review of the fish supplementation strategy that went public at this week's meeting of the Power Planning Council in Boise. The ISAB said the strategy has credible potential to benefit some weak or declining populations, but also had the potential to harm a fish population of any size.

"Current information, however, does not allow accurate prediction of the magnitudes of the harm and benefit or of the net balance," says the report. The board noted that artificial production is likely to initially increase fish abundance, which can give rise to harvest rates that stay high when production declines. "This situation leads to excessive exploitation," they say, "when either freshwater or marine productivity go down."

And this is what the basin faces today, the scientists say. "Given the variation evident in marine survival rates, the time required to address freshwater habitats, and the evidence from past hatchery and supplementation programs, we must advise that it is unlikely that increased capacity and productivity of integrated populations (the stated goal of supplementation) will provide sustained benefits over the foreseeable future."

After looking at a number of supplementation efforts in the basin, they found that smolt-to-adult returns have been "substantially lower" than targets for performance standards. "There is no evidence that similar problems will not occur in the future," they say.

With so many questions still unanswered, the scientists said it should only be used in half the situations where it might aid fish recovery, "to spread the risk and set up a system of references."

Big Bets On Supplementation Effort No Sure Thing
The science panel that judges the merit of BPA-funded fish and wildlife proposals has given poor marks to a group of supplementation actions designed to pump up Idaho's wild salmon stocks with fish raised in hatcheries and released into under-utilized streams. The strategy is a cornerstone in the region's fish and wildlife program, but many scientists question its validity.

The science panel has serious concerns about whether the suite of projects in Idaho could shed light on one of the biggest unknowns in the basin's biggest fish recovery business---whether supplementation really works. It's been used as a major selling point to fund major tribal hatchery projects, even though such hatcheries are officially called "experimental."

"It seems unlikely that the ISS [Idaho Supplementation Studies] will contribute the compelling evidence for or against supplementation that managers in the region are expecting," the Independent Scientific Review Panel said in its May 22 review. BPA spends about $3 million annually on the five Idaho projects.

The panel said a major confounding issue was that other hatchery fish strayed into both control and treatment streams. In the Salmon River, stray rates were generally low, except for the South Fork, where it was about 67 percent, according to carcass surveys. Overall, stray rates were much higher in tributaries of the Clearwater Basin--on the order of 50 percent or more.

The scientists said another problem was that some streams, like Johnson Creek on the South Fork of the Salmon River, were originally designated as control streams, then re-classified as treatment streams. A supplementation effort was started at Johnson Creek as an emergency measure to aid a rapidly declining stock, part of an effort to increase its fish numbers as part of a legal agreement among federal and state agencies and tribes that spelled out future harvest opportunities for tribal fishers [US v. Oregon].

So, some streams are now designated as "partial treatment" streams, according to ISRP Chair Rick Williams. Williams said he still hopes that the analysis phase of the ISS projects will yield some "partial answers" to the big question: the value of supplementation.

Williams said another factor that could confound supplementation studies is the ongoing effort to improve habitat in many of the areas where these studies are being conducted. He wondered if that meant the region should hold off on implementing such habitat improvements while researchers try to gauge the effectiveness of fish supplementation efforts.

Many wild fish advocates say that adding hatchery fish to streams--even fish with wild parentage--will eventually dilute the fitness of wild stocks and reduce populations. Little long-term research has been conducted in this realm, as evidenced by a recent survey of peer-reviewed studies by NOAA Fisheries. However, some recent work with steelhead has shown that hatchery fish that mate with their own kind survive at about 80 percent the rate of wild fish. The feds have a vested interest in the Idaho studies, since the wild stocks being supplemented are listed under the Endangered Species Act.

But in places like Johnson Creek, the analysis has been further confounded by using a mixed broodstock of wild and hatchery origin. The Idaho researchers have revamped their study design to address some of the science panel's earlier concerns. But the science panel said the original study design has been so compromised that they have suggested more weirs be constructed on study streams to keep out non-ISS fish.

The scientists also noted that the ISS researchers were conducting carcass surveys on only a subset of streams in the study. They said all streams must be surveyed annually, or "it will not be possible to analyze even one measure of success, namely density of redds."

Williams said the basin's other science panel, the Independent Scientific Advisory Board, which reviews scientific issues related to the fish recovery effort, would surely stir more debate on the topic when it released its report on supplementation at the June meeting of the Northwest Power Planning Council in Boise. Some fish managers, especially tribal ones, have already criticized the panel for its "anti-hatchery" bias.

The ISAB has already gone on the record with a skeptical attitude towards the supplementation strategy. In 2001, the group noted that the region's main recovery strategies all assumed that supplementation "will succeed in accelerating the desired goal of salmon restoration," with the implication that increasing hatchery production was a way to overcome habitat shortcomings. "This is an assumption with little supporting evidence," the ISAB said at the time, and recommended a thorough assessment of supplementation efforts. The group said it was essential to devise a large-scale experiment to measure the impacts of supplementation on the Columbia River Basin.

One experiment already under way is the expensive, BPA-funded Yakama Nation fish hatchery on the Yakima River near Cle Elum. It was sold as an "experiment" to find out if supplementation works and has been operating long enough to be getting some adult returns.

But the ISRP has been critical of perceived lacks in the hatchery's monitoring and evaluation effort. Designed to gauge the value of the supplementation effort, it cost BPA $3.8 million in 2002 and is expected to cost at least that much in 2003. The scientists outlined a methodology in 2001 to improve the assessment. Without it, "there is a significant risk of not learning from this large-scale experiment," they said.

In comments to the ISRP, the Yakamas said supplementation was a potential tool that could "buy time" until habitat conditions had improved enough to support enhanced natural production. They expected that a rigorous evaluation "was likely to take up to 30 years." But the tribe's response to many of the ISRP 's concerns was "inadequate," according to the science panel.

Hood River Hatchery Supplementation
The ISAB has evaluated a steelhead supplementation experiment in Oregon's Hood River Basin, and presented their findings at a BPA research review in May 2003. The basin once was home to spring and fall chinook, coho, searun cutthroat, summer and winter steelhead, but all species except the steelhead are now extinct.

USFWS biologist Bill Ardren presented information on the hatchery supplementation experiment gathered since 1991. Monitoring takes place at Powerdale Dam four miles from the mouth of the river. Though built in 1923, the dam now has a fish pass and a trap to collect data for the hatchery experiment. The dam will be removed in 2010, ending the supplementation evaluation after the second generation (F2) has returned.

Ardren speculated that preferential mate selection was taking place among natural spawners. Proportionally, he said, wild-wild crosses among natural spawners produced more offspring than hatchery-hatchery crosses or hatchery-wild crosses.

The scientists had originally assumed that mating between hatchery and wild fish would be random. Biologists are now able to investigate this issue through a pedigree study that samples the DNA from each fish to match the juveniles to specific parents. "We observed more WxW matings than were predicted," Ardren said.

Another problem that has surfaced is the loss of genetic diversity in the population because a small proportion of hatchery fish are magnified in the adult run. This is called the Ryman-Laikre effect which predicts a small family structure in hatchery fish and a high survival rate from egg to smolt. Even though smolt-to-adult survival rates for hatchery fish are normally less than for wild fish, the hatchery fish return in greater numbers because more of them are released than produced by wild fish. Biologists are concerned that the hatchery fish are less diverse, yet numerically, they can dominate on the spawning grounds.

Future work will tackle questions about the effect the hatchery program is having on the effective breeding population of wild fish. Since summer and winter runs overlap and the two races are not always easy to tell apart, biologists are wondering if the process for selecting adults for artificial spawning is hybridizing the two runs. They also want to know if just one trip through the hatchery breeding process will select for certain breeding traits.

In their review, the ISAB noted some problems as well. The hatchery master plan has achieved its 65.5 percent goal for egg-to-smolt survival since it's averaged 68 percent. However, the 4.5 percent smolt-to-adult [SAR] survival goal is not being met. The actual SAR rate has ranged from .3 percent to 1.3 percent. The ISAB notes that the average number of adult progeny produced per adult used in the hatchery program has been only 8.6 fish, well below the target of 50 fish set in the master plan.

By comparison, the naturally spawned fish had an average egg to adult survival rate of 1.2 percent and a SAR of 3.8 percent, and sometimes as high as 5.5 percent. But even though the hatchery fish have a lower SAR, their sheer number of returning fish exceeds the wild run. The percentage of hatchery-origin adults in the winter run ranged from 24.3 percent to 68.9 percent and averaged 44 percent.

Biologists are concerned about the potential for swamping the wild steelhead population with hatchery fish, leading to a loss of diversity and loss of reproductive fitness in the natural spawning population of both hatchery and wild fish. The researchers noted that the wild fish may be correcting for this by preferentially spawning with other wild fish instead of hatchery fish.

Bill Rudolph and Bill Bakke
Council's Science Board See-Saws on Supplementation
NW Fishletter, June 13, 2003

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