TY - JOUR
T1 - GnRHa-induced spawning of wild-caught jack mackerel Trachurus japonicus
AU - Nyuji, Mitsuo
AU - Fujisawa, Kazuki
AU - Imanaga, Yui
AU - Kitano, Hajime
AU - Yamaguchi, Akihiko
AU - Matsuyama, Michiya
N1 - Funding Information:
Acknowledgments We thank the students in the Laboratory of Marine Biology, Kyushu University, and Dr. Michio Yoneda of the National Research Institute of Fisheries and Environment of Inland Sea, for their experimental support. This study was performed as part of the Establishment of Rearing Systems in Jack Mackerel Program, which is supported by the Fisheries Agency of Japan. These studies were also supported in part by a Grant-in-Aid for Scientific Research (23658163) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. M. N. is supported by JSPS Research Fellowship for Young Scientist.
PY - 2013/3
Y1 - 2013/3
N2 - The jack mackerel Trachurus japonicus is a key commercially exploited fish species in Japan. The rearing experiment often provides information that is useful for understanding the reproductive characteristics of wild stocks; however, there has been no study on spawning in captive T. japonicus. In the study reported here, we induced spawning in T. japonicus caught in the wild by hook and line. Females with fully vitellogenic oocytes and males during spermiation were selected by gonadal biopsy and injected with gonadotropin-releasing hormone analog (GnRHa) mixed in molten coconut butter. This treatment was performed four times in different groups of four females and five to eight males, and each group was maintained in a 3-m3 concrete tank. We observed the first spawning at 1 or 2 days post-injection and collected between 41,690 and 149,450 eggs. Spawning was recorded on 18 consecutive days in one experiment and for 3 days continuously in the other experiments. In the former, spawning ended when the water temperature reached 23 °C and occurred mainly between 2100 and 2400 hours. These results indicate that GnRHa-induced spawning may be useful for evaluating the reproductive characteristics of T. japonicus and obtaining fertilized eggs to conduct larval experiments.
AB - The jack mackerel Trachurus japonicus is a key commercially exploited fish species in Japan. The rearing experiment often provides information that is useful for understanding the reproductive characteristics of wild stocks; however, there has been no study on spawning in captive T. japonicus. In the study reported here, we induced spawning in T. japonicus caught in the wild by hook and line. Females with fully vitellogenic oocytes and males during spermiation were selected by gonadal biopsy and injected with gonadotropin-releasing hormone analog (GnRHa) mixed in molten coconut butter. This treatment was performed four times in different groups of four females and five to eight males, and each group was maintained in a 3-m3 concrete tank. We observed the first spawning at 1 or 2 days post-injection and collected between 41,690 and 149,450 eggs. Spawning was recorded on 18 consecutive days in one experiment and for 3 days continuously in the other experiments. In the former, spawning ended when the water temperature reached 23 °C and occurred mainly between 2100 and 2400 hours. These results indicate that GnRHa-induced spawning may be useful for evaluating the reproductive characteristics of T. japonicus and obtaining fertilized eggs to conduct larval experiments.
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U2 - 10.1007/s12562-013-0599-4
DO - 10.1007/s12562-013-0599-4
M3 - Article
AN - SCOPUS:84874795719
VL - 79
SP - 251
EP - 258
JO - Fisheries Science
JF - Fisheries Science
SN - 0919-9268
IS - 2
ER -