50 
C. Kenneth Dodd, Jr. 
of 148.5 turtles per hectare. Since Brushy Creek Lake has an area of 
13.76 ha, there could be as many as 2,043 S. odoratus in the lake, 
assuming an equal population density among areas. If adjustments are 
made to confine the estimate to optimal habitat (67.3% of the lake 
surface area based on depth profiles), a minimum population of 1,375 
stinkpots in the lake would be indicated. 
Published values of stinkpot density range from 8 to 700/ ha 
(Mahmoud 1969, Iverson 1982, Congdon et al. 1986, Ernst 1986), and 
Mitchell (pers. comm.) has found densities in two Virginia populations 
at 188 and 194/ha. Given these figures, a density of 148 stinkpots per 
hectare in Brushy Creek Lake seems reasonable. 
Population Structure. Of the 135 stinkpots, 22 (16.3%) were juveniles 
(< 65 mm CL); the smallest measured 39.3 mm CL. There was no 
significant difference in CL between males and females (F = 1.30, P - 
0.26), although males averaged slightly larger (M: x = 76.8 mm, range 
66.6-90.5 mm, SD = 7.6; F: x = 75.0 mm, range 65.0-95.1 mm, SD = 
5.5). The lack of differences in the CL of adult males and females was 
not surprising since size dimorphism has not been reported for S. 
odoratus except in the extreme southern portions of its range (Tinkle 
1961, Bancroft et al. 1983). 
Most turtles were in the 65- to 79.9-mm size classes, and none were 
in the 50- to 54.9-mm size class (Fig. 2). Females outnumbered males in 
all but the 85- to 89.9-mm size class. The relationship of carapace length 
to plastron length was highly significant (Fig. 3) regardless of sex (Table 
1 ). 
The population structure of S. odoratus in Brushy Creek Lake was 
nearly identical with populations in Pennsylvania (Ernst 1986) and 
Florida (Bancroft et al. 1983). All three studies showed increasing 
numbers of individuals in age classes up to intermediate CLs, followed 
by a rapid decrease in the numbers of larger individuals. The main 
differences are not in the structure of the populations per se, but in the 
sizes of the animals. Pennsylvania stinkpots attain much larger CLs 
than Florida turtles, and northern Alabama turtles are nearly intermediate 
in this respect. 
In some other studies (e.g., Wade and Gifford 1965), the population 
structure is slightly different, showing what appears to be a more 
gradual decline in numbers of larger turtles. The reasons for such 
variation are unknown, although differences may be an artifact of 
sampling technique. Unless data are available using comparable sampling 
procedures, it may be premature to speculate on the underlying causes 
of differences in population structure reported for distant populations. 
Sex Ratio. Of the turtles larger than 65 mm CL, there were 30 
males and 83 females, or one male per 2.8 females. This ratio is 
significantly different from 1:1 ( X 2 = 12.68, P < 0.01). Proportionally 
more females were caught in the May (6.25 females/ male) and August 
