Cold weather drove hundreds of manatees to seek sanctuary this weekend in the warm-water discharge zones of South Florida power plants.
An aerial survey Monday in Broward County found 304 manatees, the vast majority herding into the cooling lakes of the power plant west of Fort Lauderdale-Hollywood International Airport and east of State Road 7.
No aerial survey took place in Palm Beach County, but officials had expected the cold to bring an influx to the power plant at Riviera Beach, where Florida Power & Light is required to discharge warm water when the temperature drops to a certain point, even though the plant has been taken out of operation to be modernized.
Extremely sensitive to cold, manatees learned decades ago that power plants could provide warm water refuges to replace the warm springs that were once abundant around the Florida peninsula. The plants suck in cold water to cool their turbines and discharge at a higher temperature.
"There used to be a lot more warm-water refuges," said Pat Quinn, Broward County's manatee coordinator. "Because we're sucking so much water from underground for human use, there's not as much water flowing out of the springs as there used to be. There used to be warm-water springs down here, and as they become less and less, the manatees started coming to the power plants."
About 270 manatees were counted Monday at the power plant near State Road 7.
Any area that draws lots of manatees will quickly get stripped of seagrass and other food. So when the weather warms up -- something the manatees sense as they come up for air -- they generally head quickly to sources of nourishment. The nearest big beds of seagrass are in the Lake Worth Lagoon.
Quinn said boaters should be aware that manatees will be moving in the next few days as the weather warms up, as the ravenous sea cows leave their warm refuges and head out in search of food.
Particularly popular travel corridors in Broward County include the Intracoastal Waterway, New River, South Fork of the New River, Dania Cut-Off Canal and the waters around Port Everglades. In Palm Beach County, manatees are frequently seen around Jupiter Inlet, Munyon Island, Boynton Inlet, Lake Wyman and the Lake Worth Lagoon.
Boats and ships remain the leading single cause of death for manatees. Statewide, 78 manatees have been killed by watercraft this year, including two in Palm Beach County and three in Broward. Although manatees are protected as an endangered species, a conservative legal group called the Pacific Legal Foundation petitioned the U.S. Fish and Wildlife Service to reclassify the manatee as "threatened," a possible step on the way to removing it from the list completely.
Although Monday's count in Broward was one of the high counts of the year, it came nowhere near the record set last January, when cold weather and optimal viewing conditions resulted in 1,192 manatees counted in a single day.
dfleshler@tribune.com, 954-356-4535 ___
Sun Sentinel | By David Fleshler Posted: 12/24/2012 8:00 am EST | Updated: 12/26/2012 2:57 pm EST