Schmid: Marine turtle populations on the west-central coast of Florida 
597 
Deletion of data with recapture intervals less than 90 
days reduced the mean growth rate of the 40-50 cm 
size class (4.7±3.0 cm/yr; n= 9, range: 2.9-12.3 cm/yr). 
The von Bertalanffy growth interval equation was 
fitted to each of the recapture interval data treat- 
ments. Estimates of asymptotic length ranged from 
77.3 to 91.4 cm and estimates of intrinsic growth rate 
ranged from 0.0852 to 0.1167 (Table 5). The growth 
interval equation for all Kemp’s ridley turtles recap- 
tured at Cedar Key had the lowest residual mean 
square, a standard that has been used to select the 
best fit growth model (Dunham, 1978). However, the 
estimated asymptotic length for this model (a=91.4 cm) 
is considerably larger than the average carapace 
length reported for nesting females (65 cm; Marquez 
M., 1994) and should therefore be considered biologi- 
cally unrealistic (Frazer et al., 1990). The estimated 
asymptotic length for recapture intervals greater 
than 180 days (a= 77.3 cm) would be more appropri- 
ate if this latter criterion is used. This model has the 
least amount of error from short-term recaptures, 
but suffers from a reduced sample size and a trun- 
cated range of carapace lengths. 
Population estimations 
The computer program JOLLY computed a survival 
rate of 0.41 (± 0.07 SE) and a capture probability of 
0.18 (±0.05 SE) for Kemp’s ridley turtles at Corrigan 
Reef. Population estimates ranged from 98.05 turtles 
in 1987 to 262.79 turtles in 1992 (Table 6). For 1987 
through 1993, the mean annual population size was 
158.50 (±112.40 SE) turtles and there was a mean of 
15.35 (±11.58 SE) marked turtles in the population 
(10% of the estimated mean population size). For 
1987 through 1992, there was a mean annual recruit- 
ment of 102.71 (±48.23 SE) turtles (65% of the esti- 
mated mean population size). 
Food 
Fecal specimens from 12 Kemp’s ridley turtles were 
examined during the course of this study. Crab com- 
ponents were identified in all specimens. In addition, 
two (17%) of the fecal specimens contained mollusc 
shells and two (17%) specimens contained a portion 
of undigested seagrass (. Halodule wrightii in one and 
Halophila engelmannii in the other). Seven (58%) of 
the fecal specimens contained unidentified crab frag- 
ments. Five (42%) of the turtles had consumed cheli- 
peds of stone crab, Menippe spp., and three (25%) 
had consumed chelipeds of blue crab, Callinectes 
sapidus. Two (17%) Kemp’s ridley turtles had con- 
sumed shark eye shells ( Polinices duplicata), one of 
which also consumed a common eastern nassa shell 
Table 4 
Mean annual growth rates of Kemp’s ridley turtles, Lepi- 
dochelys kempii, by recapture interval, netting season, and 
size class (standard deviations given in parentheses). 
Turtles were assigned to size classes by mean of initial 
and recapture SSCL. 
Mean 
SSCL 
growth 
rate 
Range 
of 
growth 
rates 
Data treatments 
n 
(cm/yr) 
(cm/yr) 
Recapture interval 
All recaptures 
24 
5.4 
(3.3) 
1.2-13.0 
Recaptures > 90 days 
16 
4.5 
(2.6) 
1.2-12.3 
Recaptures > 180 days 
13 
3.6 
(1.2) 
1. 2-5.4 
Netting season 
Within season 
10 
7.7 
(3.6) 
o 
co 
rH 
1 
t> 
Between seasons 
11 
3.3 
(1.1) 
1.2-4. 7 
Size class 
30-40 cm 
7 
4.6 
(2.8) 
1. 2-9.4 
40-50 cm 
13 
6.2 
(3.7) 
2.9-13.0 
50-60 cm 
4 
4.6 
(2.5) 
2. 2-7. 9 
Table 5 
Estimated values of asymptotic length (a) and intrinsic 
growth rate ( k ) from nonlinear regression of von Berta- 
lanffy growth interval equation for Kemp’s ridley turtles, 
Lepidochelys kempii (one asymptotic standard error in pa- 
rentheses). 
Data treatment n a k 
All recaptures 24 91.4 cm 0.0852 
(41.9) (0.0720) 
Residual mean square error = 1.3872 
All recaptures > 90 days 16 90.9 cm 0.0858 
(51.1) (0.0892) 
Residual mean square error = 2.1179 
All recaptures > 180 days 13 77.3 cm 0.1167 
(29.2) (0.0957) 
Residual mean square error = 2.0085 
( Nassarius vibex), that contained hermit crabs 
(Paguridae). The two turtles that consumed hermit 
crabs also ingested mollusc components. Cancellate 
cantharus shells ( Cantharus cancellarius) and oys- 
