OBSERVATIONS OF FLORIDA MANATEES (TRICHECHUS-MANATUS-LATIROSTRIS) AROUND SELECTED POWER-PLANTS IN WINTER

Sixty-four aerial surveys were flown during cold, winter weather betwe en December 1982 and February 1992 to provide an index of trends in ab undance of the Florida manatee (Trichechus manatus latirostris) around five Florida Power & Light Company (FPL) plants. The surveys document ed high winter use of warm-water discharges at four of the plants (Can averal, Riviera, Port Everglades, and Fort Myers). The total number of manatees sighted at the five primary plants surveyed during a single survey ranged from 6 to 765 manatees (xBAR = 330 +/- 45 manatees per s urvey); thus, up to 41% of the total Florida manatee minimum populatio n of 1,850 animals may be found on cold days at FPL plants. The number of calves sighted at the plants during winter has decreased; similarl y, for three consecutive years (winter 1989-1990 through winter 1991-1 992), the percentage of the manatees that are calves sighted at the pl ants has decreased. Although data from the surveys of FPL plants do no t necessarily reflect what may be happening with manatees located else where in Florida, a possible reduction in calf numbers, coupled with i ncreasing numbers of dead calves being documented by scientists involv ed in manatee carcass salvage work, is cause for concern in this slow- reproducing, endangered species.