Professors at Massachusetts state colleges earn about $11,000 less annually on average than their peers in other states, a gap that threatens the public system's competitive standing, according to a study released today.

The average salary of professors at the state's four-year public colleges in 2007 trailed the national average by about 13 percent, the independent survey found. The disparity was sharper in certain fields, such as biology and business administration and management.

"These disturbing numbers call into question the state colleges' ability to compete for the best teachers and scholars," Robert Antonucci, president of Fitchburg State College, said in a statement. "If we don't close the gap quickly, we are going to face more and more problems recruiting and retaining top-notch faculty."

State college professors earned an average of $76,400, compared to $87,600 nationally. Associate professors earned just over $63,000, or $9,000 less than their peers. Assistant professors, who made $55,000, trailed the national average by $5,000.

"This issue goes beyond equity to the wider question of the economic competitiveness of Massachusetts," said Peter Alcock, a member of the Board of Higher Education. "How can we continue to compete for the best faculty to educate our students and future workforce when we don't pay them what they're worth?"

Faculty salaries have lagged behind the national average for several years. In an effort to attract junior faculty, state colleges have increased the wages of new associate and assistant professors, but have not followed suit with veteran professors.

The study, conducted by Sibson Consulting, surveyed professors at Bridgewater, Fitchburg, Framingham, Salem, Westfield, and Worcester state colleges, and the Massachusetts College of Liberal Arts. The Massachusetts Maritime Academy and the Massachusetts College of Art and Design were not included because of their specific focus.