the south, and Gaspanlla Sound to the north. The results of these surveys are 

 summarized in Table 1. 



The approach selected for the low-level monitoring of Charlotte Harbor 

 dolphins was photographic identification (photo-ID) surveys from small boats (see 

 reviews bv Scott et al. 1990a; Wiirsig and Jefferson 1990). This technique has proven 

 effective in long-term studies of population-rate parameters in contiguous waters of 

 Sarasota Bay, immediately to the north (Wells and Scott 1990), and Tampa Bay 

 (Wells et al. 1995), the next bay system to the north of Sarasota. The residency 

 suggested by tagging studies in 1970-1971 (Irvine and Wells 1972) and 1984, and long- 

 term resightings of distinctive dolphins photographed by Wells (1986) during 

 surveys initiated h 1982, indicated that Charlotte Harbor would be appropriate for 

 photo-ID surveys. 



Photo-ID offers several advantages over aerial surveys for measuring certain 

 population rate parameters. The greatest advantage of using photo-ID methods is 

 the accumulation of information on the occurrence, distribution, and ranging 

 patterns of specific individuals. The ability to recognize individuals over time 

 provides opportunities to estimate abundance using mark-resight methods, to 

 evaluate possible cases of immigration, emigration, or transience, to monitor 

 individual female reproductive case histories, to determine the origins of carcasses 

 for mortality estimates, and to examine community structure (Wells 1986). 



This report summarizes the results of five years of NMFS-sponsored 

 bottlenose dolphin research in Charlotte Harbor, conducted bv the Chicago 

 Zoological Society (CZS). Annual photo-ID surveys were conducted during August 

 of each year from 1990 through 1994. The study area included more than half of the 

 region of the aerial surveys, but did not include all of Pine Island Sound, due to 

 logistical and budgetary constraints. Photographs and sighting data were collected to 

 examine trends in abundance, natality, mortality, immigration, and emigration. 



Methods 



Stu dy A re a 



The Charlotte Harbor study area includes the enclosed bav waters eastward of 

 the chain of barrier islands from the north end of Lemon Bay southward to Captiva 

 Pass, as well as the shallow Gulf coastal waters and passes immediately surrounding 

 the barrier islands (Figure 1). The southern boundary of the study area extends from 

 Captiva Pass, through northern Pine Island Sound to Matlacha Bridge, east of Pine 

 Island. To the northeast, the study area extended to the Rt. 41 bridge over the Peace 

 River in Punta Gorda, and the El Jobean bridge over the Myakka River. The region 

 is composed of a variety of habitats and conditions, including highly productive 

 seagrass meadows and mangrove shorelines, deep passes between barrier islands, 

 shallow, sandy Gulf waters, dredged channels, river mouths, and open bays. 



