A record 201 manatees died in Florida waters this year, authorities said.

At least 46 of the endangered sea cows were found dead in the weeks following a three-day freeze last Christmas, and boat collisions killed at least 46 more, said Bruce Ackerman, a marine mammal researcher with the state Department of Natural Resources.A variety of factors contributed to the other deaths.

Last year, 166 manatees were killed, up from 133 in 1988.

State officials estimate there are 1,200 to 1,500 West Indian manatees in Florida, down from an estimated 10,000 several decades ago.