PORTLAND – Amid speculation about directions Roman Catholics will take under a new pope, Maine’s bishop moved ahead Tuesday with the unveiling of a long-planned realignment of the state’s 135 parishes that is designed to address the state’s shifting demographics and critical shortage of priests.

The changes could dramatically reduce the number of weekend Masses celebrated in Catholic churches throughout the state as well as energize Maine’s 234,000 lay Catholics to take larger leadership roles in parish life, Bishop Richard Malone said during a news conference.

The plan, to be implemented in 2010, does not call for the closing of any parishes or the sale of any church property, but reduces the number of parish groupings, called clusters, in the diocese from 31 to 27. It assigns a certain number of priests to each cluster.

“People tell me that this is the most significant change in parish structure for our diocese since the 1920s, when three dozen churches were built to keep up with burgeoning populations at the time,” Malone said.

Under the plan, one priest would serve as pastor with pastoral vicars, or associate pastors, assigned to clusters with more than one priest.

A cluster is a group of neighboring parishes that share resources – from a priest’s time to a multichurch youth event.

Among the changes, the plan would:

. Combine the Bangor area cluster with the Orono-Old Town cluster. That configuration would put 11 churches – in Bradley, Old Town, Orono, Bangor, Brewer, Hampden, Winterport and Indian Island – into one cluster. Four priests, instead of the current seven, would administer the sacraments at those churches.

. Reduce the number of priests in Washington County from four to two.

. Reduce the number of priests from two to one in Eagle Lake, Wallagrass, Fort Kent, St. Francis and Allagash.

. Reduce the number of priests in central Aroostook County from six to three.

Geography and already bare-bones staffing will prevent some clusters from losing priests.

Parishes in Ellsworth and on Mount Desert Island, along with their summer mission churches, would continue to be staffed by two priests and a third who summers in the area.

In June 2004, Malone announced what he called a New Evangelism Planning Committee and appointed 10 laypeople, three priests, two nuns and a deacon, from Fort Kent to Biddeford, to serve.

The panel submitted its recommendations to the bishop on Jan. 6. After receiving comment from priests and diocesan leaders, Malone approved the plan that he unveiled Tuesday.

Malone and members of the committee did not rule out that one long-term result may involve closing churches and rectories in rural communities or communities that have more than one parish.

The bishop stressed Tuesday that the plan was driven by the church’s mission “to be an evangelizing people.”

“It will involve the laity in new and very strong ways,” Malone said, “and will call for very significant collaboration in the leadership of the church as we go forward – collaboration of the clergy and the laity in new forms of leadership.”

There are about 95 diocesan priests serving in parishes around the state. Because of anticipated retirements and the number of men studying for the priesthood, that number in five years is expected to drop to somewhere between 60 and 65, Malone said.

The plan calls for staffing churches with more than two dozen priests from religious orders, although they have not been assigned to specific clusters.

About a half-dozen committee members, including Bill Hogan of Veazie, attended Tuesday’s news conference,

“Our challenge was to distribute the priests as sparsely as we could to make sure everyone had the privilege of the Eucharist,” Hogan said in an earlier interview. “Number one in my mind was, we know we have limited resources and a large, spread-out geography. How do we bring various parishes together to work with each other when some do not have a resident pastor?”

The answer was to create clusters, or groups of churches, that are close together geographically and assign a certain number of priests to each cluster. Clusters have existed in the diocese since 1999 but were smaller, and churches in them did not necessarily share priests.

Many did offer joint events for youth groups and collaborated for special events. In 2000, churches in Bangor, Brewer, Hampden and Winterport held two joint Masses at the Bangor Civic Center to celebrate the Jubilee year that were attended by an estimated 4,500 worshippers.

Parishioners and priests in the new clusters are to begin meeting this summer to determine which resources – such as worship space, clergy, lay ministers and programs – are available in each church.

Malone said Tuesday that he is looking to the laypeople and clergy to make the tough decisions about how resources, including a priest’s time, will be distributed in five years.

“This way we will also strengthen the leadership of our parishes because we will have the skills and gifts that many laypeople bring that most of us priests are not trained in,” Malone said.

“The idea is to strengthen the work of the church by bringing larger groups of people together to pool all of their resources – time, talent, treasure – in a manner that’s more effective than any one parish could do on its own,” he said. “This whole project is going to challenge all of us who are Catholic in Maine to a new appreciation of who we are as church.”

Dioceses around the country recently have implemented realignments with mixed results.

Parishioners in Boston have protested a reorganization announced last year by Archbishop Sean O’Malley that would have closed nearly a fifth of the area’s 357 parishes.

Parishioners in some Boston-area parishes reacted by occupying churches and picketing the bishop’s office. Last month, O’Malley announced that he would not close several churches where vigils had been held.

Malone’s decision to include the laity in a consultative process might help the Maine diocese avoid that kind of dissension.

The dioceses of Green Bay, Wis., and Albany, N.Y., have used a similar process to close churches over the past decade, according to Commonweal magazine, an independent journal of opinion edited and managed by lay Catholics.

Representatives from both dioceses reported that the realignments had not been easy, but that the slower, more gradual process which included the laity had seemed to ease resentments.