Table 8. Components of the inter-annual differences in abundance estimates. N\ is the 

 Method-3 abundance estimate for Year 1 (Table 3). Mortality is estimated 

 conservatively by the sum of the stranded dolphins reported between surveys 

 (September - August) in S. Sarasota and Charlotte Counties. Reproduction 

 includes two components. The first is the number of YOYs added to the 

 population in Year 2. The second is the number of older calves, which can serve 

 as an index of calf survivorship and/or attractiveness of the area for raising 

 calves. The change in the number of calves is calculated by subtracting the 

 number of calves in Year 1 and the number of YOYs in Year 1 (who would be 

 calves in Year 2 if all survived) from the number of calves in Year 2 (Table 5). 

 (This approximation also assumes that the number of calves that become 

 independent of their mothers each year remains constant.) Transients present in 

 Year 1 but not in Year 2 are subtracted; those present in Year 2 are added (Table 4). 

 Fluctuations in the number of residents due to movements into or out of the 

 area or due to inability to photograph these dolphins even when present can be 

 estimated by first calculating the difference between Year 1 and Year 2 in the 

 number of marked residents in the catalog (R = M - No. of Transients) and then 

 adding the e-timated number of unmarked residents (R * (1 - m/n), Tables 3,4)- 

 The Sum of all of these columns can then be compared with N2, the Method-3 

 abundance estimate calculated for Year 2 (Table 3). The unaccounted-for 

 difference between the Sum and N2 is likely due to imprecision and bias of the 

 abundance estimates or the components listed in the table. 



Mortality Reproduction Transients 



Yr 1- Yr 2 N x (Year 2) YOYs Calves Yr 1 Yr 2 Residents Sum N^ 



1990-1991 307 -6 +11+4 -25+18 -32 277 265 



1991-1992 265 - 18 +7-23 -18+6 - 2 217 238 



1992-1993 238 - 6 +17+33 - b + 15 + 60 351 372 



1993-1994 372 - 4 +8-2 -15+34 +9 402 385 



