Superintendent Maryann Perry reported at last week's School Committee meeting that many students, some 200, are in study halls at the high school.
In an interview this week, Marblehead High Principal Layne Millington echoed the superintendent's comment.
The school has a sizable number of students in study halls each period, and the root cause is the school's staffing, he said.
"We have too few staff to offer enough courses to keep students out of study halls," he said.
A further complication, he said, "is the way science labs historically have been scheduled at the high school; science classes effectively take up one full class slot and one-third of another. Under the current system, that leaves 2/3 of the second slot unusable for anything but study halls."
Finding a solution for the science lab hurdle is tied to the staffing shortage.
"The staffing issue is being pursued through budgetary channels but will not easily be addressed because of the level of funding needed," he said. "We do have some ideas about solving the science lab hurdle (e.g. creating electives that meet for 2/3 of a class slot) but this discussion is moot until the staffing levels are addressed."
The superintendent told School Committee members that the Marblehed High School principal will update the committee as the school year progresses.