A maximum of 2 manatees per survey was sighted in Charlotte Harbor (Charlotte 

 County; Figure 1) and small numbers of manatees were consistently sighted in Pine Island 

 Sound, Matlacha Pass, San Carlos Bay, in the lower reaches of the Caloosahatchee River, 

 and in Estero Bay (Lee County). The few sightings in Charlotte Harbor are noteworthy 

 because manatees are often sighted by residents in this area (Moore 1951b, Hartman 

 1974), and 36 manatees were counted in Charlotte Harbor during a summer aerial survey 

 by Hartman (1974). Manatees were sighted in the Upper Caloosahatchee River (Glades 

 and Hendry Counties) only in November. Manatees were not sighted near the warm- 

 water refuge in the Orange River, Lee County (Hartman 1974), but the area was not 

 surveyed in December when ambient air and water temperatures were coldest. 



A few manatees were consistently sighted between Charlotte Harbor and Tampa 

 Bay. The animals were sighted in Lemon Bay, Roberts Bay, and Little Sarasota Bay, and 

 were often near the channel of the Intercoastal Waterway. 



North of Sarasota County, manatees were primarily sighted in rivers emptying 

 into Tampa Bay, including the Hillsborough, Alafia, Manatee, and Little Manatee 

 Rivers. Our observations in Hillsborough and Manatee Counties may have been hampered 

 in September by cloud cover and in October by turbid waters resulting from recent 

 flooding. 



Winter Concentrations 



Manatees were observed near warm-water refuges (Hartman 1974) only during the 

 December flights. A total of 40 manatees was sighted at the two warm effluents of the 

 Gibsonton Phosphate Plant in the Alafia River (Hillsborough County). Eight manatees 

 were sighted in the Big Bend Power Plant effluent (Hillsborough County), and a cow and 

 calf were observed just offshore of the effluent. Five manatees were observed at the P. 

 L. Bartow Power Plant effluent (Pinellas County), and two manatees were observed near 

 the intake canal. A single manatee was sighted in the intake canal of the Anclote Power 

 Plant (Pasco County). Use of the Bartow and Anclote power plants has not been 

 specifically reported, but manatees were sighted previously at these locations (A. B. 

 Irvine, personal observation) and were mapped by Irvine and Campbell (1978). 



Information is not available to determine if the manatees sighted at the heated 

 effluents were residents of the Tampa Bay area or were migrants. In either case, 

 manatees arrived at the Gibsonton effluents through a ship channel and have been sighted 

 previously in and adjacent to ship channels of Tampa Bay (Hartman 1974, A. B. Irvine, 

 personal observation), making them potentially vulnerable to increased shipping caused 

 by OCS development. Large concentrations of wintering manatees in western Florida 

 have also been identified at the artesian springs of Crystal River, Citrus County (Powell 

 1978, Hartman 1979), which is north of our study area, and at a heated effuent in the 

 Orange River, Lee County (Hartman 1974), which was not surveyed during the December 

 flights. Manatees usually arrive at these warm-water refuges during the fall as 

 surrounding waters cool and leave as water temperatures warm in the early spring, but 

 warm season movements are unknown. 



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