Program and Abstracts(PDF)

Presentation 7
A CHALLENGE TO TECHNOLOGY DEVELOPMENT OF THE YEAR ROUND EGG
PRODUCTION IN KAN-PACHI AMBERJACK Seriola dumerili : ADVANCED
SPAWNING TECHNIQUES
Kazuhisa Hamada,* 1 Kiyoshi Soyano, 2 Keiichi Mushiake 1 and Takuro Hotta 3
1
National Research Institute of Aquaculture, Fisheries Research Agency
2 Nagasaki University Institute for East China Sea Research
3 Goto Station, National Center for Stock Enhancement, Fisheries Research Agency
*Email: kazhama at affrc.go.jp
Amberjack (Seriola dumerili, Kan-Pachi in Japanese) is one of the most important species in
marine fishery resources in Japan, having recently become a major target of aquaculture
production. As aquaculture process, the stable production and distribution of quality eggs are
needed to obtain healthy larvae/fry. However, spawning and quality egg production techniques
were not yet established.
In Kan-pachi amberjack, spawning season of the wild brood fish is from November to March
around the waters of China Kainan islands and Vietnam (the South Chaina Sea). Juveniles grow
to about 10- 15 cm in total length with body weights of about 25- 50 g in April in the waters of
China, and then they are exported to Japan as aquaculture seeds. On the other hand, in Japan the
spawning season of greater amberjack reared in net cages under the natural conditions ranges
from May to June. Thus, there is a lag of about six months in the spawning season compared to
Chinese wild fish. The delay in the spawning season appears a drawback that it affects directly
the initial size of fry at the beginning of the grow-out culture. Consequently, the difference in the
initial size would reflect on feed and labor costs and then commodity price. To solve the present
issues, therefore, we have developed maturity control techniques by the environmental control
based on the technologies with spawning induction in December (winter) of yellowtail (Fisheries
Research Agency (FRA), Japan).
We first succeeded in egg production of Kan-pachi amberjack in December (2006) in the
world. We have subsequently achieved the early egg production for the last four years. The size
of our artificial seeds from the eggs in December reached finally to about 25 cm in the total
length and about 250 g in body weight at the end of May in the next year, which is almost equal
or superior to imported seeds from China. Furthermore, considering production cost, our artificial
seeds from the eggs in December cost 289 to 324 yen for a juvenile, while 350 to 600 yen for a
Chinese seed with an annual fluctuation. From the viewpoint of cost in the seed production, we
can claim that our seeds produced by the advanced spawning technologies are more effective.
We conclude that the present environmental control technologies in maturity and early
spawning established in Kan-pachi amberjack would not only contribute to the establishment of
well-planned production and stable supply of quality seeds of Kan-pachi amberjack, but also be
applied to the wide-range temperate/tropical marine species.
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