Hatchery Versus Wild Fish: Latest Round Leads to Petitionby Bill Rudolph
NW Fishletter, March 21, 2003
A report published in a recent issue of the journal Science has found evidence that hatchery-raised salmon may develop some traits that make them unfit for helping to boost wild fish populations.
But next week, a group of retired, well-known Northwest fishery biologists will be petitioning the US Secretary of Commerce to add a new rule that would add many hatchery stocks to the "evolutionarily significant units" or ESUs of mostly wild fish stocks on the West Coast that are now protected under the Endangered Species Act. The petition is expected to be filed March 24 in Washington, DC.
The March 14 Science article (vol. 299, No. 5613) was published as a huge debate heats up in the Northwest over whether hatchery fish can be used to help increase the numbers of wild fish listed under the Endangered Species Act, with the eventual goal of de-listing them.
The Science study said several generations of fish raised in a hatchery environment produced increasingly smaller eggs, a trait that is "maladaptive in nature" because natural selection favors large eggs. The scientists--four from Canada and one from Kentucky--also looked at four British Columbia rivers where wild chinook populations had been supplemented by varying numbers of hatchery salmon. The trend toward smaller eggs was evident in the two rivers where more hatchery fish spawned with wild stocks. Smaller eggs mean smaller juveniles that could be at a disadvantage when competing for food with fish hatched from larger eggs, the scientists said.
"These data indicate that unintentional selection resulting in small egg size is potentially a serious concern for the long-term success of salmonid supplementation efforts," the authors said, "but the effect could be minimized through modified breeding practices."
Washington state hatchery managers say they already take great pains when breeding salmon, and that the small-egg phenomenon is not evident in their own programs. "Our experience does not see the same results as the Science article," said John Kerwin, who heads the Washington Department of Fish and Wildlife's hatchery program.
Kerwin said the state's captive broodstock efforts for spring chinook in the Tucannon and Methow rivers include breeding protocols that try to ensure spawners represent a wide spectrum of genetic traits. He said one instance where the state has seen a tendency towards smaller fish and smaller eggs has been in a coho hatchery in south Puget Sound on the Puyallup River, where net and recreational fisheries that target larger fish have probably allowed the smaller coho to predominate returns to the hatchery. Kerwin also cautioned that smaller returning fish could be due to environmental factors such as ocean conditions.
As part of an effort to update the ESA status of listed West Coast stocks, federal scientists are working to develop a hatchery policy that will attempt to gauge the effects of hatchery fish that spawn with wild ESA-listed stocks. The work began after a federal judge ruled that the feds had violated the ESA by not offering hatchery coho stocks the same protections as the wild component of the Oregon coastal coho stock [Alsea Valley Alliance v. NMFS]. Since the agency had previously listed the hatchery component of the stock in the same "evolutionarily significant unit" with the wild component, Oregon District Court Judge Michael Hogan ruled that the hatchery fish must be protected as well. The agency did not appeal the decision, and decided instead to revamp its hatchery policy.
However, environmental and fishing groups appealed Hogan's decision to the 9th US Circuit Court of Appeals, where oral arguments are now slated for May 8. The Niners put a stay on Hogan's decision pending the appeal's outcome.
A recent NOAA Fisheries draft of fish status updates outlined the feds' thinking on a new policy to determine whether a hatchery stock will be designated as part of a listed ESU. It spelled out four categories for hatchery populations, differentiated by the extent that each group was derived from native, local stocks and had been genetically affected by artificial propagation.
NOAA Fisheries biologists have no schedule yet for the new policy's release, but the status updates should be completed by November, said federal biologist Mike Delarm. Since the new hatchery policy must be used to help determine the final updates, the new policy must be completed before then.
The pro-hatchery fish group of retired biologists claim that most of the criticism of hatchery salmon "is based on comparisons between divergent stocks of fish, which is not a true comparison between wild and hatchery fish from the same stock." The group also said these arguments are clouded by uncertainties, with too few well-designed studies to provide the hard data to test assumptions.
The group--including retired federal scientist Gary Wedemeyer, Jim Lannan, William McNeil, Don Amend, and Charlie Smith--in 2001 circulated a paper on hatchery and wild salmon. Saying that genetics arguments supporting wild fish were "politicized" science, the biologists pointed out that arguments over "fitness" are theoretical and ignore the fact that both hatchery and wild fish "are acted upon by the same evolutionary forces during the majority of their life cycle in the ocean."
Regardless of how the ESA legally defined a species, "the gene remains the fundamental unit of heredity," the retired biologists said. When some genetic resources are lost, they cannot be restored. "It is now entirely possible that there is greater genetic diversity in hatchery salmon populations than in some wild populations," they said in their paper.
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