SARASOTA — Coastal areas disturbed by development are becoming prime targets for non-native fish invasions, a marine biologist said Wednesday.

Steve Bortone, director of the Sanibel-Captiva Conservation Foundation Marine Laboratory, spoke on the final day of the Charlotte Harbor Conference at Mote Marine Laboratory.

The conference marked the end of the fifth and final year of Mote's Charlotte Harbor Program, during which universities, government agencies and private research organizations conducted wide-ranging studies of the estuary.

One subject that scientists in the project did not originally plan to study was the Mayan cichlid, a non-native fish first documented in Florida in the Everglades 22 years ago.

Aaron Adams, director of Mote's Charlotte Harbor field station, and his team discovered the fish in the harbor in July 2003.

Since then, Mote and state scientists have found many Mayan cichlids, as well as other exotic species, such as the armored catfish, mostly in areas disturbed by development.

"When an area is disturbed, it upsets the natural balance and creates an ecological open space that gives non-natives a foothold," Adams said. "Another thing is that Florida is not very species-diverse, so there are more options for invasion because there aren't many native species."

Florida is home to many terrestrial exotics, and some, particularly plants, have become pests.

"With terrestrial exotics, we said, 'Oops,' years later, and now we're spending a lot of money fighting them," Adams said. "In Florida, we're not there yet with invasive fish. Will they have negative impacts? We don't know yet, but it makes sense to find out. Once you're invaded, you can't get them out, but with understanding, we might be able to control them."

Because non-natives thrive in altered environments, exotic fish indicate that Charlotte Harbor is not the "pristine" habitat touted by some.

On a scale of 1 to 10, 1 being dead and 10 being pristine, Adams rated Charlotte Harbor about a 7.

"We need to get real about how we describe the habitat," he said. "We run the danger of fooling people that it's in good shape."

Other presentations Wednesday covered movement patterns of bonnethead sharks, the effects of Hurricane Charley on smalltooth sawfish and nutrient concentrations.

John Worth, director of the Randell Research Center in Pineland, discussed his research on the harbor's first commercial fishermen, Cubans who started fishing the area in 1710.

Recently discovered records show that, for years, about a dozen Cuban fishing vessels targeted mullet almost exclusively during late fall and winter, returning to Cuba with several hundred thousand pounds of salted fish and roe in time for Lent.

"Cubans didn't eat fish as a matter of choice," Worth said. "It was an obligation: They had to eat it during Lent."