Roman Catholic Bishop of Idaho Sylvester Treinen, who has watched his flock increase from 45,000 to 75,000 in his 26 years at the post, has announced his early retirement.

Pope John Paul II granted Bishop Treinen's request for retirement, the bishop said in a press release Wednesday. Canon law requires bishops to retire by age 75. Bishop Treinen will be 71 in November."For the past three years, since the summer of 1985, I have prayed much over this decision," he said. "I have often consulted my spiritual adviser, and I have studied the matter thoroughly. There were no pressures except the usual burdens of any important office. I have nothing to prove by staying on longer - no records to break."

Although he suffered a massive heart attack in 1981, he said an official church announcement from Rome incorrectly stated he resigned because of ill health.

Bishop Treinen said he would serve as "apostolic administrator" of the Roman Catholic Diocese of Boise until the next bishop is installed, probably in six to eight months.

Bishop Treinen, who was named bishop of Boise by Pope John XXIII in May 1962, said his reasons for requesting early retirement included his age and years in the office, the large area of the diocese and "the ever-increasing burdens of administration.

"I have loved the people of our Gem State, Catholics and those of other religions and no religion," he said. "Of course, my affection for all of you will continue, and if anything, it will grow stronger."

Gov. Cecil Andrus, a Lutheran who has known the bishop for two decades, said he understood Bishop Treinen had asked the Vatican if he could be given a parish near an Idaho trout stream. He lists fishing among his hobbies.

Andrus said he was saddened by the retirement of a "gentle" man, yet "a very strong moral leader for the people of the state of Idaho."

This year, Bishop Treinen wrote the Department of Energy to object to the plutonium refinery proposed for the Idaho National Engineering Laboratory, which would produce weapons-grade materials for nuclear arms.

He is credited with prompting the Idaho Legislature to require sanitary facilities in fields for farm workers, creating a mission in Cali, Columbia, Catholic student centers at the three state universities and a prison ministry.