BANGOR — University of Maine System trustees approved a 2012-13 budget today that, for the first time in 25 years, won’t increase undergraduate tuition and mandatory fees charged to state residents.

System administrators presented a balanced $529 million budget for seven universities that includes a $2.3 million decrease in state funding, according to a news release.

Trustees agreed to freeze tuition and mandatory fees despite a projected .5 percent enrollment drop in the 2012-13 academic year, according to budget documents.

To lessen the impact of the tuition freeze, the system will spend $1 million from reserves and $2.1 million of the state appropriation that had been designated for strategic purposes.

Total annual in-state tuition and mandatory fees range from $7,300 at the University of Maine at Presque Isle to $10,594 at the University of Maine in Orono.

Chancellor James Page, who has faced controversy over university hiring and spending practices since he started in March, said the system’s current path isn’t sustainable over the long term.

Page said he will work to stabilize the system by promoting performance-based funding and reallocating savings from administration and infrastructure improvements to support teaching, research and public service.