In urban areas with scant resources and dwindling numbers of students, the diocese relies heavily on the enrollment of children of other faiths.
But when the church community takes stock of the challenges facing Catholic schools, a debate surfaces: Is it worth the struggle, especially if many of the students are not even Catholic?
Jeffrey Burns, an archivist for the Archdiocese of San Francisco and a faculty member at the Franciscan School in Berkeley, said that question usually arises each time a school is being considered for closure. Some wonder whether the resources would be better spent on adult education or on religious education for public school children who are Catholic, he said.
"They say, 'If there aren't many Catholics left, what are we doing?' Can we afford to keep these schools open?"
Catholics still have a strong presence in most parochial schools. In the city of Oakland,
70 percent of Catholic-elementary-school children are Catholic. Throughout Alameda and Contra Costa counties, the average is 88 percent.
Some schools serve mostly Catholics, such as St. Elizabeth School in East Oakland's Fruitvale neighborhood. But at St. Martin de Porres, the last Catholic school in West Oakland, about half the children are of other faiths.
In a reference to Oakland's sobering homicide rate, the highest in a decade, DeMarco added, "We either invest in them now when they're young or look around we're burying them. This is what Catholic education has done for the inner city. It's giving the kids a chance. It's giving them hope."
But in the last 10 years, Catholic schools in some of Oakland's toughest neighborhoods which served a large number of non-Catholic, African-American students have closed, or nearly closed.
Diana Adams, the last principal at East Oakland's St. Louis Bertrand Elementary School, said the pastor became concerned in the late 1990s that few of the parish's Catholic children attended the school. Many were poor immigrants from Mexico and Central America who couldn't afford the tuition, and he felt the nearby public schools weren't a good option for them.
So the pastor brought Monarch Academy, a tuition-free, non-religious charter school, to the site. In turn, the parish's Catholic school with its mostly non-Catholic children moved to the nearby St. Cyril School. (The diocese has since adopted a standard evaluation process, and pastors no longer have the authority to close their parish schools, DeMarco said.)
After five years, the merged St. Cyril-Louis Bertrand Academy was shut down as well.
The move to close St. Cyril-Louis Bertrand came as a shock to families in East Oakland's Millsmont neighborhood, which had seen three nearby Catholic schools close their doors in less than 10 years.
"This community was really in a crisis," Adams said. "I had parents and students calling and crying."
Just days after the news, a charter school representative called to inquire about the prospect of opening a school there. Adams later would be hired as principal of the new school, called Millsmont Academy.
There was nothing religious about the charter school proposal. But, Adams said, it was "an answer to prayer."