The present study was carried out to resolve the growing phases of the Loggerhead Turtle,
Caretta caretta (
Linné), which were raised from just hatch out stage to the 4.5 years old in the Aquarium, since the knowledge on the Sea Turtle is very poor today.
The carapace length, carapace width, head length, head width, shell depth and body weight were measured every month after the hatching and the data were treated by the biometrical method (Fig. 1).
The result may be summarized as follows: 1. The growth rate of the carapace length and body weight from 1.5 years to 4.5 years found to follow the logistic curve of the Robertson formula (Fig. 2, 3).
2. The relationships of the age (
t year) and the carapace length (
L mm) and body weight (
W gr) of the Turtles are able to be expressed by the following formulae.
LA=1041/1+exp1.1309-0.7038
t LB=972/1+exp1.0877-0.7107
t WA=110000/1+exp3.543-1.331
t WB=91000/1+exp3.449-1.346
t 3. The growth of reared Turtles may attain 1040mm in maximum carapace length and 110kg in body weight, and attains the egg laying size in about 6-7 years.
4. The alternating point of growth rates (
dLA/
dt,
dLB/
dt,
dWA/
dt,
dWB/
dt) was calculated as 3 years in the carapace length and 4 years in the body weight.
5. The relationships between those meristic characters were able to be expressed by the formula of allmetric growth equations.
(
x) (
y) range in mm
Carapace length Carapace width
y*=0.1709
x1.4189 39-53
Carapace length Carapace width
y**=1.0608
x0.9678 70-740
Carapace length Shell depth
y=0.4706
x1.0081 39-245
Carapace length Head length
y=0.9643
x0.7787 74-740
Carapace length Head width
y=1.1306
x0.6821 74-740
Carapace length Body weight
y=0.0004910
x2.8317 39-740
Carapace width Body weight
y=0.0004431
x2.9147 43-740
6. An inflection point was found in the relationship between carapace length and carapace width at 57.25mm in carapace length. It suggests the ecological or physiological or physiological changes occuring in Turtles. For example, morphological changes found in the upper jaw in the pointed end at the early growth stage (Fig. 7, Plate 1).
7. At the criticl point, the proportion of body forms which were derived from the allometric growth, was able to be divide into two stages. The inherent body shape was constituted from this critical point onward.
8. The growth gradient was taken a postero anterior gradient type by the body axis. The gradient was with high values in the posterior part.
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