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Know the West

The facts about fish control

  Dear HCN,

In a May article titled "Debate rages over fish poisoning" (HCN, 5/7/01: Debate rates over fish poisoning), very subjective views of the impacts of fish-control chemicals antimycin and rotenone on the environment were presented. It's ironic that despite the article's recognition of the growing fears of the uninformed public toward fish-control chemicals, it fed those fears with anecdotal accounts and unqualified information contrary to common sense and scientific facts.

The article reports a New Mexico rancher's contention that his sheep must have drunk stream water tainted with antimycin used in a project to restore the Rio Grande cutthroat trout. According to the U.S. Fish and Wildlife Service and Jicarilla Apache Nation biologists, potassium permanganate was used to neutralize the antimycin at the bottom of the treatment area. A lack of dead fish in the rancher's stream suggests that little, if any, antimycin persisted that far downstream. The following spring, two lambs were reported born dead with enlarged kidneys, but no veterinary necropsy reports were provided. The lambs could have died of a number of common diseases or other complications. Antimycin quickly degrades naturally, and is easily neutralized with potassium permanganate.

Antimycin was not "invented" in the 1970s, as the article said; it's a naturally occurring substance that was discovered in the 1940s. It doesn't paralyze the cells of fish gills or suffocate fish and other creatures. Like rotenone, it interferes at the molecular level with oxygen transfer during cellular respiration. Fish are more susceptible to antimycin than are mammals and birds.

The article quotes an opponent of antimycin, who states that "dumping" antibiotics into creeks is equivalent to the widespread use of antibiotics in hospitals, and will result in the survivors showing increased resistance to antimycin. The portrayal that this "horror-movie scenario" will occur from the use of antimycin in fisheries management is completely unfounded and technically incorrect. Antimycin is not produced by fungi (like penicillin) but by bacteria Streptomyces, and it has no antibacterial qualities.

Although rotenone had nothing to do with this New Mexico "event," the article erroneously characterizes the Lake Davis, Calif., northern pike eradication as a failure. It is unknown whether any northern pike survived the treatment or were reintroduced. The article claims that the City of Portola lost much of its water, 62 people were hospitalized, and the economy dried up overnight, all the results of a single rotenone treatment. The truth is less dramatic. The City of Portola lost none of its water supply, and the California Department of Health Services in August 1998 again certified Lake Davis as a potable water supply. The local economy was depressed prior to treatment, but it has blossomed since the treatment, due to increased revenues from the excellent trout fishing now present in Lake Davis. Although some Portola area citizens went to the local hospital with health complaints during the treatment, follow-up investigations by the California Environmental Protection Agency concluded that none were the result of poisoning.

The selective use of fish-control chemicals has restored numerous populations of threatened and endangered species of fish, including bull trout in Oregon, golden trout in California, Apache trout in Arizona, and many other trout populations in California, Wyoming, Colorado and Utah. The American Fisheries Society Rotenone Stewardship Program Web site, www.fisheries.org/rotenone, contains an array of public and technical information on the safety of rotenone that could be used as guidance for disclosing information on antimycin.

American Fisheries Society Fish Management Chemicals Subcommittee,
Task Force on Fishery Chemicals;
American Wildlands,
Federation of Fly Fishers,
Greater Yellowstone Coalition,
Idaho Fish and Game,
Montana Fish, Wildlife, and Parks,
Montana Trout Unlimited,
Turner Endangered Species Fund,
Wyoming Trout Unlimited

This letter was shortened due to space limitations.