Marine wildlife officials are closely monitoring water temperatures off the Sun Coast. That’s because of new information that as many as 25 percent of manatees who were found dead over the last two winters were killed by cold water. Manatees need to live in water that’s warmer than 68 degrees and as we’ve reported here already, many have now been spotted moving into pockets of warm water in area bays and rivers. The south Florida museum says more than seven hundred manatees died last winter, a quarter of them from cold water stress.