Just as the heavy summer boating season begins, Jacksonville University researchers say the number of manatees in the area has increased.

The single-day manatee count is now 217, up 15 percent from the previous high of 189 in 2012.

Researchers conduct the counts from the air by flying slowly just above the water, spotting a manatee, and following its path to the larger group to get the total number in the area. They surveyed the Lower St. Johns River Basin on Monday and the Intracoastal Waterway on Wednesday.

Quinton White, executive director of marine science research at JU, said the count, which includes 198 adults and 19 calves, is just a minimum number. "There are more out there," he said. "We didn't see them all."

Due to migratory patterns, the population is highest at this time of year. He said he wasn't surprised by the numbers, but pleased.

Most deaths also occur in June.

"If you see a manatee, slow down," White said.

The decrease in deaths can be attributed to stronger state regulations like slow-speed and no-wake zones, White said.

Andy Garrett, manatee rescue coordinator at the Florida Fish and Wildlife Conservation Commission, recommends wearing polarized sunglasses to help spot manatees in the water. "The nose is just the tip of the iceberg," he said.

Overall, the statewide population is 6,250, prompting the U.S. Fish and Wildlife Service to plan removing the mammal from the endangered species list.

From 2013 to 2015, the number of manatees in the area decreased, but the lowest point in recent years was in 2009, when researchers counted just 73 manatees.

The number was likely due to a drought that raised salinity levels and killed the grass areas manatees feed on, forcing the mammals to move out of the research area, said Gerry Pinto, a JU researcher.

Though the food supply in the St. Johns River area has decreased, researchers said the population increase here and around the state is a sign conservation efforts are working.

If the species' endangered status goes away, state and local regulations will remain in place, White said.

JU, which has surveyed the area for over 20 years, partners with the city of Jacksonville to conduct the research.

"It's a success story," Pinto said. "That doesn't mean we need to stop protecting it."

This year there has been one manatee death caused by a boat, near the Talleyrand terminal in Jacksonville, Pinto said.

Ariella Phillips: (904) 359-4162