Tucson's two main purveyors of higher education have opposite fortunes this fall: One's student body has shrunk substantially while the other's is the biggest it's ever been.

Enrollment at Pima Community College is in a double-digit decline after recent changes to its admissions rules, a larger drop than at many other community colleges in the state.

The University of Arizona, meanwhile, is headed for an all-time high enrollment of 40,000 students or more.

At PCC, the number of registered students is down 11 percent compared with this time last year.

The college had 29,755 students as of last week. That's 3,581 fewer than the 33,336 enrolled in fall 2011.

By comparison, enrollment is down 1 percent at Central Arizona College in Pinal County, and 8 percent at Cochise County's community college.

Maricopa County's 10 community colleges have seen a systemwide decline of about 3 percent, officials there said.

Community college enrollment tends to rise during recessions when unemployment is high, then tapers off as the economy improves.

Universities, on the other hand, often do better in stronger economies when more can afford their higher tuition.

PCC spokesman C.J. Karamargin said this year's enrollment decline "was not unanticipated" and is due to many factors such as Arizona's improving economy.

Recent changes to admission rules may also be partly to blame, he said, though it's "too early to definitively assess the impact."

The changes, which took effect earlier this year, initially required applicants to prove they can read, write and do math at a minimum seventh-grade level in order to enroll in degree-seeking programs.

The main test PCC uses to measure proficiency has been criticized as unsuitable by a national group that advocates for fair testing standards.

PCC has backed off the new rules somewhat, for example, by allowing students weak only in math to take credit courses that aren't math-based.

At the UA, officials are celebrating a milestone: a preliminary head count that's up about 2 percent compared with the 39,236 students enrolled at UA last fall.

"It's looking like our total enrollment will be around 40,000 or a little above that, which is the largest it's ever been," said Kasey Urquidez, UA's dean of admissions.

The growth is especially welcome since enrollment was virtually stagnant last year.

The boost comes after the UA stepped up efforts to attract more students through high school visits, parent nights and other recruiting programs, Urquidez said.

Contact reporter Carol Ann Alaimo at calaimo@azstarnet.com or at 573-4138.