| Project/Area Number |
15570067
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Animal physiology/Animal behavior
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| Research Institution | Nagasaki University |
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Principal Investigator |
SOYANO Kiyoshi Nagasaki University, Institute for East China Sea Research, Associate Professor, 環東シナ海海洋環境資源研究センター, 助教授 (80260735)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIMATSU Atsushi Nagasaki University, Institute for East China Sea Research, Professor, 環東シナ海海洋環境資源研究センター, 教授 (00184565)
NAKAMURA Masaru Univ.of the Ryukyus, Tropical Biosphere Research Center, Professor, 熱帯生物圏研究センター, 教授 (10101734)
TODO Takashi Hokkaido Univ., Graduate School of Fisheries Science, Associate Professor, 大学院・水産科学研究科, 助教授 (60303111)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2003: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | lunar cycle / honeycomb grouper / maturation / spawning / spawning migration / biotelemetry / 性成熟 / 産卵行動 / 性ステロイド |
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| Research Abstract |
Honeycomb grouper, which is distributed in the sub-tropical and tropical area in Pacific Ocean, is known as a lunar-related spawner. However, details of gonadal development and spawning in this species are not well understood. In this study, we investigated the gonadal development and hormonal changes in female collected from the fringing reef area around Sesoko Island during spawning season and observed the spawning in artificial conditions. Moreover, we investigated the spawning migration to the outside of fringing reef for spawning using biotelemetry method.
Gonadosomatic index increased rapidly and reached the maximum level around the full moon in late May or early June, when ovaries were occupied with oocytes of the tertiary yolk stage. The fish of maturational size disappeared from the fringing reefs for a few days after the full moon. When the fish appeared again in the same reef area, there was no vitellogenic oocyte in the ovary. These results indicate that the fish spawned in the area outside the fringing reefs after the full moon. In artificial conditions, the final oocyte maturation and spawning were observed for a few days after the full moon, while the maturated fish migrated outside the fringing reefs in natural conditions. The spawning of individuals was carried out for three or four days. This results elucidated clearly that honeycomb grouper is a lunar-related spawner.
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