A sluggish economy coupled with a severe lack of affordable housing on the Vineyard may be responsible for stagnant and, in some cases, falling enrollments reported by Island schools this week.

Hardest hit were kindergarten classrooms in Edgartown and Tisbury, where numbers are down by a combined 23 students. The numbers at other schools are largely similar to last year, but - after years of steady growth - the flattening out of enrollment may be a harbinger of lower school populations in the future.

"It's clear that from 1994 to 1999, we were rapidly growing, but there's a dropping out here," said school superintendent Dr. Kriner Cash. "At this point, with the cost of living here, it's hard to say what we could project for the next 10 years. But some families are leaving. I know of three that left the other week to move off-Island."

At the regional high school, where preliminary enrollment figures show just a slight increase from 795 to 814 students, principal Margaret Regan said, "The economy has a huge influence on who comes and who doesn't."

Barely more than a year ago, the high school saw a big increase in enrollment during last-minute summer registration. "Forty kids just sort of showed up and registered for the high school," Mrs. Regan said. "This year, it was more like 10 kids."

But the real indicators of what's to come remain the lowest grades, which enroll the children of the Island's youngest families. That's where Mr. Cash pointed to significant drops and wondered aloud whether the housing crisis is taking a toll on this slice of the Vineyard's demographics.

"Edgartown had 36 in the kindergarten, and now it's just 28," he said. "That's a big drop-off." In Tisbury, the drop was even sharper, falling from 38 to 23 kindergartners.

With few houses selling for under $300,000 and year-round rentals now priced well over $1,000 a month, the housing market could well usher in an era of falling enrollments.

"Oak Bluffs still has a couple places where year-round rentals open up, but Tisbury is tight," said Mr. Cash. "These towns are locked up as far as really affordable and available housing is concerned."

Lack of housing could be the reason that Tisbury School saw overall enrollment fall from a 359 to 339 and the Edgartown School from 382 to 351, an 8 per cent drop. The Martha's Vineyard Public Charter School may have contributed to those decreases as well, adding 15 students for a total of 159.

Enrollments at other schools were almost unchanged. West Tisbury School increased from 382 to 387. In Oak Bluffs, attendance rolls total 458, down only two students from last year. Chilmark's Menemsha School saw a slight uptick, growing from 52 to 58 students.

The Island school census is undertaken at the beginning of October each year as part of contractual agreement between the six towns. The information is used to compute the shares paid by each town into the regional high school budget.

Enrollment figures at the high school are expected to hold steady at about 800 for the next few years, based on the number of students currently sitting in the Island's fifth through eighth grade classrooms.

But Mr. Cash said his goal over the next two years is to tap into other data to make better predictions. Getting such data means hiring a consultant to research the latest Census findings, birth rates and building starts. Lacking that kind of information, all Mr. Cash can say now is that he expects school enrollment numbers to flatten out.

Compared to the last decade of growth - characterized by new school building, expansion projects and the hiring of more teachers - the next few years could give school leaders a little breathing room.

"The good part is that these buildings need a respite," said Mr. Cash. "They couldn't stand much more growth in these facilities."

Still, the notion that the Island school population may be ebbing raises the question whether leaders even need bother considering a regional middle school. Last year, when school census numbers were rising compared to 1999 figures, some school committee members and town selectmen renewed the call for such a facility.

And whenever leaders talk about land use on high school property, inevitably mentioned is the need to "save room for a middle school" somewhere on the campus. Mr. Cash's response is to go back to the need for better population projections.

In contrast to the anecdotal evidence of people leaving the Island, Mr. Cash said he knows of many Island families who are staying put and having children. "If my teachers are any indication," he said, "there are a lot on maternity leave."