MIAMI (Reuters) - A record number of endangered manatees died in Florida waters this year, according to the state’s Fish and Wildlife Conservation Commission.

A woman pets an endangered Manatee while swimming in the Crystal River in Homosassa, Florida, February 9, 2005. REUTERS/Marc Serota

In a preliminary report on Friday, the commission said its Fish and Wildlife Research Institute had documented 419 manatee deaths in state waters between January 1 and December 11, the most for any year since record-keeping began in 1974.

The previous worst year for the mammals was 2006, when 417 deaths were documented in Florida. A lower-than-average total of 337 deaths was reported in 2008.

Manatee death counts can swing wildly from year to year and the wildlife commission has cautioned in the past not to read too much into a single year’s statistics.

Along with an uptick in deadly encounters with boats, Florida’s manatees faced a string of cold spells this year and a high mortality rate among infant manatees.

Cold-related deaths, at 55, were more than twice last year’s total.

The West Indian manatee, related to the African and Amazon species and to the dugong of Australia, grows to 10 feet and more than 1,000 pounds (450 kg). Its wrinkled and whiskered face has won the hearts of generations.

Although they have no natural enemies, manatees are routinely crushed or drowned in canal locks, run over by speeding boats or hurt by fishing line and hooks. They are vulnerable to cold water in winter and to deadly blooms of “red tide” algae.

The Florida population is believed to have increased slightly in recent decades, in part due to boat speed restrictions. As a result, developers and boat industry interests have argued for easing restrictions to allow more construction of boat slips.

State scientists counted a record high number of 3,807 manatees in Florida waters last year, topping the previous high in 2001 by more than 500.