July 26, 2013

Bighorn sheep testing shows sick animals without disease

Two bighorn sheep ewes and their lambs are photographed during a survey conducted by the California Department of Fish and Wildlife. Both state and national wildlife agencies were investigating a disease outbreak within the Mojave National Preserve.

Desert Dispatch

BAKER • Preliminary survey results by wildlife agencies in the Mojave National Preserve show that a few sick desert bighorn sheep have tested negative for pneumonia, according to an official of the California Department of Fish and Wildlife.

More than 20 sheep in a herd of about 200 bighorns have died. One of those animals was confirmed by laboratory tests to have pneumonia, coordinator Regina Abella said on Friday.

Pneumonia can pass to bighorn from domestic sheep and goats. It is believed an angora goat found 12 miles east of Old Dad Mountain near Baker may have been the culprit for the outbreak, according to a news release from the National Park Service.

Desert bighorn have no natural defenses to diseases carried by domestic animals and the mortality rate for infected animals is 50 to 90 percent.

In California, all bighorn sheep are fully protected under the Department of Fish and Wildlife code which is a classification made to animals that are rare or face possible extinction, according to Abella. However, the desert area has historically held a very healthy and robust population of the breed, she said. In fact the desert bighorn were recently used to help populate other herds in nearby states, she said.

One concern of the wildlife agencies is that the summer marks the beginning of rut, or mating season, which could potentially influence long-distance movement by the older male bighorns. Jeff Villepique of the National Park Service said that officials were nervous about the desert herd potentially carrying the disease to nearby Nevada bighorns.

Two weeks ago officials also did a three-day helicopter survey of Old Dad Mountain and other nearby herds, according to the Mojave National Preserve website. Scientists hoped to asses the current distribution and status of the disease. After the survey on July 19, scientists were still compiling and interpreting the data but noted significantly fewer desert bighorn were observed on Old Dad Mountain compared with previous surveys, according to the report.

Nearby herds appeared to be healthy and in good condition.