Last fall, officials at the University of Minnesota Duluth couldn't help wondering: Where are the freshmen?

The number of new students had dropped dramatically — by more than 10 percent — between 2011 and 2012. It was the first time in years that the freshman class was shrinking.

That was the wake-up call, says Andrea Schokker, the executive vice chancellor.

When she started digging into the reasons, she said, she made a surprising discovery. "We really weren't doing a lot of recruiting," she said.

It turns out that UMD had been riding a wave of surging enrollment for about a decade. During that time, it didn't have to work too hard to drum up interest, she said, because word of mouth was enough. Until now.

"We said, 'This isn't going to work,' " she said. So last year, UMD launched its most aggressive recruiting campaign in years. It hired bilingual recruiters to work with Spanish and Hmong communities, and ramped up efforts in the Twin Cities, home to nearly 40 percent of its students. For the first time, Schokker noted, UMD even started reaching out to prospective students in its own back yard — Duluth.

The result: The freshman class jumped to 2,060 students this year, up from 1,881 last year — a 9.5 percent increase.

In a sense, UMD was slow to join the marketing campaign for college students, Schokker said. But officials found that it pays to spread the word about what the campus has to offer, from its science and engineering programs to its North Shore backdrop.

Like other colleges, UMD is fighting an uphill battle, demographically speaking. The number of high school grads has been sliding since 2008, according to the Minnesota Department of Education, and that means colleges are competing for a shrinking pool of candidates.

Even now, the freshman class hasn't rebounded completely from last year's decline, Schokker acknowledged. "We haven't gone back up to where we were, but we've made a lot of gains in the last year."

maura.lerner@startribune.com