MOXEE, Wash. -- Members of the Martinez family have raised sheep in Central Washington for about 75 years and sometimes wonder how long they will be able to continue.

Like sheep ranchers across the West, they face many challenges. Declining grazing leases, hiring sheepherders through cumbersome H-2A guestworker regulations and coyotes, cougars, bears and wolves that prey on their flocks.

Carol Martinez, 73, and her sons, twins Simon and Mark, 43, and Nick, 38, have about 5,000 ewes. That's half the number 30 years ago, when Carol's late husband, Simon, and his three brothers ran the operation.

The sheep are normally split into seven herds in the summer and 11 sheepherders are hired through the federal H-2A guestworker program. They are all members of the De La Cruz family of Peru and have been with the Martinezes for 11 years.

"They are entrusted with our livelihood and they do an exceptional job," Mark Martinez said. "We do not have high turnover."

Annual contracts may be renewed twice for a maximum of three years and they must spend 90 days in their home country every three years. The Martinezes pay transportation from and to Peru, wages of $750 a month that includes two weeks of paid vacation a year. They provide food and housing.

The H-2A program is vital to their operation but it is expensive, Carol Martinez said.

"It takes a lot of time. When you want people here you can't guarantee they will be here because there are so many agencies to go through," she said.

Cognizant of lawsuits against other sheep ranchers by farmworker advocates alleging mistreatment and poor pay, she said the fact the De La Cruz men keep returning is evidence of good conditions.

The Martinez operation dates back to 1915 and 1917 when Carol's father-in-law, also named Simon, and his brother, Julian, immigrated from Spain after the rest of their family was died in war.

The Martinezes own some open range at their ranch east of Moxee and lease scattered grazing ranges from the Lower Yakima Valley to the Entiat Valley, north of Wenatchee. The sheep are taken to the family's camp at Mabton for shearing and lambing from early January through mid-April. Wool is sold. Lambs are sold for meat in August and September.

Federal and state agencies and private owners no longer lease out as much grazing land as they once did because of environmental concerns including habitat demands for sage grouse, which is under consideration for protection under the Endangered Species Act.

Sheep also have to be kept away from bighorn sheep because of the presumption they give them diseases, Carol said. The U.S. Fish and Wildlife Service and state Fish and Wildlife want healthy bighorn herds for hunters, she said.

Last August, an ewe was killed and a sheepherder's border collie was injured by a predator. They believe it was their first loss to wolves, which are protected by state law. It was on Forest Service grazing land near Blewett Pass.

"One of a wolf's fangs hooked onto the pelvis of the border collie. Had it been a sixteenth of an inch the other way it would have opened her insides and we would have lost her," Mark Martinez said.

There wasn't enough evidence for officials to confirm the sheep as a wolf kill, but wolves returned the next day, he said.