Determination of maturity in male hawksbill turtle <Emphasis Type="Italic">Eretmochelys imbricata</Emphasis> in captivity based on tail elongation and plasma testosterone level |
| |
| Authors: | Masato Kobayashi Tomohito Shimizu Koichi Okuzawa Kiyoshi Soyano Kenzo Yoseda |
| |
| Institution: | (1) Yaeyama Station of the Stock Enhancement Technology Development Center, Seikai National Fisheries Research Institute, Fisheries Research Agency, Ishigaki Okinawa, 907-0451, Japan;(2) Graduate School of Science and Technology, Nagasaki University, Nagasaki Nagasaki, 852-8521, Japan;(3) Chitose Field Station, National Salmon Resources Center, Fisheries Research Agency, Chitose Hokkaido, 066-0068, Japan;(4) National Research Institute of Aquaculture, Fisheries Research Agency, Minami-ise Mie, 516-0193, Japan;(5) Institute for East China Sea Research, Nagasaki University, Nagasaki Nagasaki, 851-2213, Japan;(6) National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hatsukaichi Hiroshima, 739-0452, Japan |
| |
| Abstract: | To determine the sexual maturity of fourteen male wild-caught hawksbill turtles straight carapace length (SCL) range 63–79 cm]
held in captivity, we investigated their hormone levels in blood and morphological characteristics. Male turtles were divided
into two groups: five individuals showing mating behavior (group A) and nine individuals not showing mating behavior (group B).
Then, seasonal changes of plasma testosterone of both groups were studied. We also tried to determine male maturity based
on tail elongation (TE) index, i.e., the ratio of tail length (TL) to SCL. Plasma testosterone level of group A gradually
increased during premating and then sharply declined to low levels between mating and postmating seasons. In contrast, that
of group B remained low during the experimental periods. The distinct seasonal changes of plasma testosterone levels of groups A
and B correlated with their maturity. Furthermore, males were clearly divided into mature and immature based on TE values
>0.35 and <0.33, respectively, corresponding to results based on plasma testosterone levels. Our results indicate that TE
can be used more conveniently and accurately to determine maturity of male hawksbill turtles in captivity. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
