2003 Fiscal Year Final Research Report Summary
A study on early life ecology of abalone species and factors affecting their mortalities in southern Japan
| Project/Area Number |
13460083
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAWAMURA Tomohiko The University of Tokyo, Ocean Research Institute, Associate professor, 海洋研究所, 助教授 (30323629)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yoshiro The University of Tokyo, Ocean Research Institute, Professor, 海洋研究所, 教授 (90280958)
HORII Toyomitsu National Research Institute for Fisheries Science, Section Head Researcher, 研究室長(研究職)
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| Project Period (FY) |
2001 – 2003
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| Keywords | abalone / early life ecology / reproductive ecology / factors affecting mortality / recruitment |
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| Research Abstract |
The reproductive biology and early life ecology of abalone, Haliotis discus discus, H. madaca, H. gigantea and H. diversicolor, which inhabit in southern area in Japan, were investigated by field observations and laboratory experiments in this study. The factors affecting recruitment of the northern species Haliotis discus hannai, which has more information on its reproduction and ecology in the early life stages than the southern abalone species, were analyzed and discussed.
Epidemic spawning of the small abalone Haliotis diversicolor appeared to be synchronously with typhoon events. The larval settlement and initial survival of post-larvae could be strongly influenced by sediment on the settlement substrata and wave disturbance. The dietary conditions and water temperature in their habitats could affect the survival and growth rates of juveniles. The radula development in H. diversicolor was different from that in H. discus hannai, suggesting the main diets and thus habitat of H. diversicolor are different from those of big abalone species.
Larvae and post-larvae of big southern abalone species, H. discus discus, H. madaca, H. gigantea, appeared from October to January. However, any associated spawning cues were not detected. Densities of the post-larvae of these big species were much lower than that of H diversicolor. Successful reproduction of the big abalone species may be inhibited due to the low density of their spawning populations.
As present major factors affecting recruitment of H. discus hannai, seawater temperature during winter, density of spawning adults, and dietary conditions for post-larvae were suggested.
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Research Products
(25 results)
