required to detect an increasing trend and a CV of 0.07 is required for a decreasing 

 trend. 



Assuming that the calculated estimates and variances are the true population 

 parameters, then a less conservative z-disthbunon can be used and the maximum 

 CVs would be 0.16 (increasing trend) and 0.23 (decreasing trend). Conversely, if a 

 more-conservative 2-tailed test were used, the maximum CVs would be 0.02 

 (increasing trend) and 0.03 (decreasing trend). We chose the 1-tailed t-distribution 

 option because it better fits the situation of considering a change in only one 

 direction at a time and because it could be argued that calculated variances may not 

 truly represent those of the population. 



Estimation procedur es: Natality 



Natality was calculated as the proportion of dolphins in each sighting 

 considered to have been born within the calendar year. Though the total number of 

 calves was recorded for each group sighted, only the subset of calves considered to be 

 young-of-the-year was considered to be relevant to the measurement of natality 

 (Wells and Scott 1990). The average proportion of young-of-the-year was calculated 

 for each year. 



Estimation procedures: Mortality 



We obtained stranding records from the Southeast U.S. Marine Mammal 

 Stranding Network (D. Odell, pers. comm.) for bottlenose dolphins recovered from 

 southern Sarasota, Charlotte, and Lee counties from 1979 through 1994 to estimate a 

 minimum mortality rate for the Charlotte Harbor area. We examined photographs 

 of dorsal fins of carcasses provided by Bob Wasno of the Lee County Department of 

 Community Services, Tom Pitchford of the Florida Department of Environmental 

 Protection, and Mote Marine Laboratory s Marine Mammal Stranding Program. 

 We used photographs of animals that died during the period 1990 through 1995 and 

 were recovered within the counties encompassing the Charlotte Harbor study area. 

 Stranding records from outside our specified study area may be included because the 

 exact locations of strandings within Lee County were not available and Lee County 

 waters extend beyond our Charlotte Harbor study area. Photographs of the stranded 

 animals were examined to determine if the markings occurred post-mortem or if 

 decomposition obscured recognition. 



Estimation procedures: Immigration/Emi gration/Residency/Transience 



We were unable to calculate rates of immigration and emigration for the 

 dolphins in Charlotte Harbor, because the criteria we have used in other areas (eg., 

 Tampa Bay, Wells et al. 1995) were too restrictive for use in this project. To calculate 

 a rate of immigration, we needed to identify "permanent" movement into or out of 

 the study area during our survey period. "Permanent" is defined as being present or 

 absent for a period of at least two consecutive years (Wells and Scott 1990). For an 

 immigrant, we would have to document that the animal was not present for at least 

 two years prior to its first appearance in the catalog, and that it was seen in the study 

 area during each subsequent survey session (tor at least two years). Thus, by 



