Rescue teams on the ground and in the air continued the search yesterday for a Canadian man who became stranded with his wife seven weeks ago.  Sergeant Kevin McKinney of the Elko County Sheriff's Office says about 20 searchers on horseback and all-terrain vehicles scoured a network of dirt roads for 59-year-old Albert Chretien. McKinney says at least one airplane flew over the area. Chretien and his wife, Rita, became stranded in late March after getting stuck on a muddy road in the Humboldt-Toiyabe National Forest en route to Las Vegas. Albert Chretien set out on foot three days later and hasn't been seen since. Rita Chretien was rescued Friday by hunters. She spent four days recovering at St. Lukes hospital in Twin Falls before returning Tuesday to her home in British Columbia.