SAN FRANCISCO — California Fish and Game officials are proposing to kill endangered Sierra Nevada bighorn sheep when they come in contact with domestic sheep believed to transmit highly contagious fatal diseases to the wild herds.
"The ramifications of allowing potentially infected animals to travel back to native bighorn herds and spread disease could be far more disastrous to bighorn recovery than the loss of a single animal through lethal take," said a state Fish and Game notice of the proposed regulation published last month.
Several environmental groups who saw the notice mounted protests this week, calling for the removal of domestic sheep from federal grazing lands in the rocky Eastern Sierra habitat of the bighorns.
"The proposal to kill wild bighorns to 'protect' them from domestic sheep is unwise and unethical," said a letter Monday from the Center for Biological Diversity and Friends of the Inyo. "What is necessary is to get domestic sheep away from bighorns now."
The federal government listed the elusive and agile creatures as an endangered species in 2000 -- after the bighorn population in the central and southern Sierra Nevada had dwindled to a low of 100 in 1995.
In recent years, the population has climbed to an estimated 350 animals, but officials say that has increased the potential for contact with domestic sheep that carry pneumonia and other diseases that can wipe out bighorn herds.
"We are willing to sacrifice an animal that is diseased or potentially diseased, because of the devastating consequences," said Vern Bleich, the Fish and Game biologist who heads the species recovery team.
Bleich said a similar strategy has been applied in Montana, although bighorn sheep there are not listed as endangered.
Department officials said that after reviewing public comments they received during a 30-day period that ended Monday, they will decide whether to authorize the capture and, if necessary, the killing of any of the endangered bighorn sheep.
Herds of the stocky, powerful sheep once were scattered along the crest and eastern slopes of the Sierra Nevada from the Sonora Pass south. Experts say there may have been 1,000 sheep when Gold Rush prospectors arrived in the mid-1800s.
Bighorns were hunted for their meat. But there also was a die-off in the 1870s west of the Kern River that was attributed to scabies from domestic sheep.
Predation by mountain lions and other animals is believed to have accounted for more than half of the deaths of bighorns in the past quarter-century.
Disease from domestic sheep, which once grazed extensively in the mountains, probably played a major role in the decline of the bighorn population, according to a federal plan for recovery of the species.
"Domestic sheep and goats in or near bighorn sheep habitat remain the greatest disease threat to the persistence and restoration of the bighorn sheep in the Sierra Nevada," said the May 2003 draft report by the U.S. Fish and Wildlife Service.
The biggest concern, biologists say, is that wild and domestic sheep might rub noses, allowing for transmission of disease. And that can happen either when domestic sheep stray into the wild or when a bighorn ram approaches a domestic flock, especially during the rutting season.
The solution is simple, said Daniel Patterson, a biologist and ecologist with the Center for Biological Diversity.
"Get rid of the domestic sheep," he said. "There is no such thing as a grazing right on public land.... If the agencies do not back off, we very likely will be looking at a lawsuit against federal and state agencies for failing" to do everything possible to protect the bighorn.
Livestock owners are granted government permits to keep their flocks on public land.
Officials said concerns about disease five years ago led to the removal of domestic sheep from tens of thousands of acres of the Inyo National Forest, where most of the bighorn population lives. And they say they are studying the possibility of withdrawing sheep grazing permits for parts of Humboldt-Toiyabe National Forest, where about 20 bighorns live.
The U.S. Forest Service allows 6,500 domestic sheep to graze on 175,000 acres there.
Over the next year, said Forest Supervisor Bob Vaught, the agency will study whether it can keep domestic and wild sheep separate.
Both groups of animals are being equipped with radio collars so their movements can be tracked. And two seasonal employees will be hired -- one to stay with the domestic sheep and another with the bighorns.
If the two populations make contact, Vaught said, the state Department of Fish and Game will be called in. "It might be necessary to capture or kill a bighorn," he said. "The preference would be capture them ... and quarantine them" to see whether they contracted any disease.
Vaught said he was reluctant to remove land from domestic sheep grazing permits until the situation can be assessed.
The concerns about disease, Bleich said, are greater in the Toiyabe forest than in the Inyo because the domestic sheep are closer to the bighorns.
Lesa Eidman, executive director of the Wool Growers Assn. in Sacramento, said that sheep help provide fire protection by clearing undergrowth. She disputed the assertion that they were responsible for disease in bighorns. "Our industry finds it important to be the best stewards of the land, and by no means do we want to see our sheep having a harmful effect on endangered species," she said.