Florida ? Most boaters speed through manatee-protection zones even though they care about the threatened mammals and believe they are obeying speed restrictions, according to a study released Tuesday by the University of Florida.

The study was conducted between August and October 2006 in Volusia County, Fla., where doctoral candidate John Jett crouched in vegetation along the St. Johns River and clocked the speeds of passing boats.

Of 1,669 boats studied, about 55 percent exceeded speed limits, he found.

As he recorded their speeds using a stopwatch and a laser range finder, Jett wrote down the boats’ registration numbers. Later, he located the owners and mailed them surveys about their speeds and their attitude toward manatees.

Of the 236 people who responded, 84 percent said they fully complied with speed limits and 71 percent agreed that manatees were worth protecting even at the cost of boating regulations.

Watercrafts killed 92 manatees last year in Florida. As of May of this year, they had killed 30.