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ISAB: Go Slow on Supplementation
Until Unknowns Answered

by Barry Espenson
Columbia Basin Bulletin - June 6, 2003

The harms, potentially, outweigh the benefits of supplementing naturally spawning salmon and steelhead populations with infusions of hatchery fish in most situations, according to a scientific panel.

But the magnitude of the effects produced from those wild/hatchery integrations

  • positive or negative
  • cannot at this point be accurately measured, says the Independent Scientific Advisory Board's June 4 report.

    The panel advises that the practice of "supplementation" be used sparingly in the Columbia River Basin until carefully designed and monitored experiments can find answers for the many associated scientific uncertainties.

    The report, "A Review of Salmon and Steelhead Supplementation," fills more than 250 pages and draws on existing literature about supplementation projects in the basin. The ISAB reviewed the genetic risks, and models of the demographic benefits, of supplementation, performance indicators to evaluate supplementation, decision-making tools for supplementation risk-benefit assessment, and surveyed the status of Columbia River Basin supplementation projects.

    NOAA Fisheries and the Northwest Power and Conservation Council last year requested that the ISAB "consider the benefits and risks of supplementation to natural populations of salmon and steelhead, and whether natural and artificial production could be integrated to increase the capacity and productivity of the combined population for the foreseeable future." The report was also forwarded to the Columbia River Inter-Tribal Fish Commission, which along with the other two entities helps select the ISAB membership.

    ISAB Chairman Eric Loudenslager and member Daniel Goodman will present findings from the report to the Council during its meeting next week in Boise. Ad hoc ISAB member Richard Williams, who chairs the Council's Independent Scientific Review Panel, will also participate.

    NOAA Fisheries is charged with protecting and guiding the recovery of 12 Columbia Basin salmon and steelhead stocks that are listed under the Endangered Species Act. As a result, it has a strong interest in assuring that hatchery processes do not negatively affect listed naturally spawning stocks.

    The Council's fish and wildlife program funds numerous hatchery projects, including supplementation programs. The Council program is funded by the Bonneville Power Administration. CRITFC's member tribes

  • the Nez Perce, Umatilla, Yakama and Warm Springs
  • manage supplementation and other hatchery programs and have been among the strongest advocates of expanded supplementation.

    The report's "adopted" definition of supplementation (from the Regional Assessment of Supplementation Project) is "the conservation of the target population, i.e., to maintain or increase natural production, while maintaining the long-term fitness of the target population and keeping the ecological and genetic impacts on non-target populations within specified biological limits."

    The primary aim is increased naturally spawning populations by releasing hatchery-origin fish that return as adults to spawn in the wild among natural-origin fish.

    The ISAB report says that the many uncertainties regarding supplementation have spawned considerable controversy. Some believe the management strategy will produce an increased abundance of natural-origin salmon and that refined hatchery practices can reduce the risks to wild stocks. Others doubt that the abundance increases can be obtained and say there is a high probability that supplementation will cause significant harm, reducing the overall productivity of the naturally spawning population.

    "The conclusions that can be drawn from the collective body of existing empirical information relevant to supplementation is that there is credible potential for a benefit to very small wild populations and credible potential for harm at any population size," according to the report. "Current information, however, does not allow accurate prediction of the magnitudes of the harm and benefit or of the net balance."

    Among the beneficial mechanisms that could be produced from hatchery-wild interactions are: increased nutrient supply to the freshwater system from an increased number of salmon carcasses; increased aggregate productivity owing to the much higher egg to smolt survival rate in the hatchery phase, and increased genetic effective population size caused by the larger total number of adults, according to the report.

    Harmful effects could be: depression of genetic diversity because of over-representation of small numbers of parents in the hatchery phase; increase exposure to disease; increased exposure to predation; exceeding the carrying capacity of the habitat, and depression of wild spawning productivity because of domestication selection in the hatchery phase.

    A memo accompanying the document summarizes the scientists' conclusions:

    The ISAB offered five recommendations: "Implementing these more rigorous experimentation protocols should improve the scientific understanding of whether supplementation can contribute to salmon and steelhead recovery at a tolerable cost to natural spawning fitness of wild populations," according to the memo.

    As of Thursday morning NOAA Fisheries officials had not had a chance to review the document.

    "As always, we're open to new information. We'll be reviewing that document carefully," said Rob Jones, NOAA Fisheries chief of harvest and hatcheries for the Northwest region's Salmon Recovery Division.

    "Supplementation right now is experimental," Jones said, as managers attempt to solve some of the uncertainties that the ISAB report notes. He said that of 192 artificial propagation programs in the Columbia River Basin, 74 are focused on some sort of supplementation.

    "There's information evolving all the time. This is a subject that's getting a lot of attention," Jones said. The agency is in the process of reviewing the Endangered Species Act status of 27 Pacific salmon and steelhead evolutionarily significant units (ESUs). An ESU is a population, or group of related populations, of salmon or steelhead.

    At the same time it is developing a new hatchery policy to guide its deliberations in establishing ESUs and making the "risk analyses" that decide if a fish stock is threatened with extinction and thus worthy of ESA protection. The coast-wide review is part of NOAA Fisheries' response to a U.S. District Court ruling which held that the agency made an improper distinction under the ESA in how it treated artificially propagated fish in its ESA status determinations. Judge Michael Hogan said the agency had gone contrary to the ESA by including hatchery stocks in designating ESUs, then leaving many of those hatchery stocks unlisted.

    The ISAB information comes in plenty of time to inform those processes," said NOAA Fisheries' Garth Griffin. The agency produced a preliminary draft hatchery policy that was distributed for comment to state and tribal co-managers early this year. NOAA is now working on a draft that will be offered for public comment.

    The Independent ISAB was established by the Council and the NOAA Fisheries to provide independent scientific advice and recommendations on issues related to regional fish and wildlife recovery programs under the Northwest Power Act and the Endangered Species Act.

    The ISAB's membership includes

    Related Sites:
    ISAB report:

    Barry Espenson
    ISAB: Go Slow on Supplementation Until Unknowns Answered
    Columbia Basin Bulletin, June 6, 2003

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