Matsumoto et at: Sexual maturation in a captive Rhincodon typus based on observations made over 20 years 
85 
A 140 0 
O 120.0 
E 
CT> 
c 
9 80.0 
c 
<D 
O 
c 
o 
o 
0.0 
AT concentration ♦ W ater tem parature 
♦ 
♦ 
< 
► . A ♦♦ 
♦ * ♦ 
♦ ♦ * , 
♦ ♦ 
* * 
► ▼ 
♦ A ♦ A 
♦ 
♦ ♦ 
♦ 
♦ ♦ 
♦ ♦ ♦ 
♦ 
♦ f 
♦♦♦♦ ♦ 
♦ 
X 
♦ 
* « H « 
♦ 
♦ ♦ A 
A 
AAA^aaAaM A A ^ A a A AAV^ A L 
-1 1-1- 
A A 
A . AA A A ’ 
i a a a a 
■ 1 —■— r r t mI 
30.0 
26.0 
22.0 
0) 
r—+■ 
CD 
CD 
3 
~o 
CD 
CD 
c 
~s 
CD 
o 
o 
16.0 
C?> r$> r& c& c& f'O' •O' 'O' V 5 V 5 V* V 3 
# # && # # V ® <9 ^ <9 ^ <9 <9 <9 V 9 <9 f / ^ d? 
B 
CD 
C 
c 
o 
c 
CD 
O 
c 
o 
o 
Q_ 
□ P4 concentration ♦ Water temparature 
4.0 
3 0 - 
2 0 - 
1.0 - 
0 0 £ 
□ 
□ 
□ 
♦ 
□ 
♦ 
♦ ■ 
□ ♦ 
n 
♦ 
□ 
□ 
♦ 
□ 
□ 
□ 
□ 
□ 
□ ' 
32.0 
- 30.0 
- 28.0 
♦ 1- 26.0 
24.0 
2 - 
CD 
~X 
CD 
3 
~o 
CD 
— t 
2 - 
c 
—s 
CD 
o 
o 
□ 
-I-1-1-1— 
m 
16.0 
A .-A .O _•£> .O 
c ? 3 c ? 3 c ? 3 c?* c ? 3 c ? 3 c ? 3 ^ ^ ^ 'O' •O •O \ x N N N 
o? # ## ^ ^ d?A* ^ ^ ^ ^ I t* o?/v Q <9 <9 
^ <<& ^ <jp ^^9^ <<& <(& <(& 
Figure 7 
Relationship between water temperature and concentrations of (A) testosterone (T) and (B) 
progesterone (P4) from May 2008 through December 2013 in a male whale shark (Rhincodon 
typus) at the Okinawa Churaumi Aquarium in Japan. The period covers the 3 developmental 
periods of the clasper: short (T: r 2 =0.42, P<0.01; P4: r 2 =0.26, P<0.01), elongating (T: r 2 =0.06, 
P=0.59; P4: r 2 =0.14, P=0.40), and completed (T: r 2 =0.14, P=0.17; P4: r 2 =0.01, P= 0.78). The 
background colors of white, light gray, and dark gray indicate the short, elongating, and 
completed periods, respectively. 
als are needed to further advance the biology of the 
well-known but mysterious whale shark. 
Acknowledgments 
We express our gratitude to the Yomitan Fisheries Co¬ 
operative for collecting the whale shark used for these 
observations. We acknowledge H. Miyahara for provid¬ 
ing us the opportunity to perform this research. We 
thank both A. Uno and K. Aoki from the Nihon Uni¬ 
versity, for assistance with laboratory analyses, and R. 
Nozu, T. Tomita, and Y. Obayashi for their comments 
on this manuscript. We recognize S. Uchida, M. Toda, 
M. Nakazato, A. Yamashiro, K. Murakumo, and other 
colleagues for their valuable information and advice. 
Literature cited 
Awruch, C. A., N. W. Pankhurst, S. D. Frusher, and J. D. 
Stevens. 
2008. Endocrine and morphological correlates of repro¬ 
duction in the draughtboard shark Cephaloscyllium la- 
ticeps (Elasmobranchii: Scyliorhinidae). J. Exp. Zool. 
309A:184-197. 
Compagno, L. J. V. 
1984. FAO species catalogue. Vol. 4. Sharks of the 
world: an annotated and illustrated catalogue of shark 
species known to date. Part 1—Hexanchiformes to Lam- 
niformes. FAO Fish. Synop. 125, 249 p. FAO, Rome. 
Gelsleichter, J., and A. N. Evans. 
2012. Hormonal regulation of elasmobranch physiol¬ 
ogy. In Biology of sharks and their relatives, 2 nd ed. (J. 
