| Project/Area Number |
01045029
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
YAMAZATO Kiyoshi Professor, Dept. of Biology, University of the Ryukyus, 理学部, 教授 (80044973)
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| Co-Investigator(Kenkyū-buntansha) |
BIRKELAND Ch グアム大学, 臨海実験所, 教授
RICHIMOND Ro グアム大学, 臨海実験所, 助教授
SAKAI Kazuhiko Assistant Professor, Marine Science Center, University of the Ryukyus, 熱帯海洋科学センター, 講師 (50153838)
HIDAKA Michio Associate professor, Dept. of Biology, University of the Ryukyus, 理学部, 助教授 (00128498)
UEHARA Tsuyoshi Professor, Dept. of Biology, University of the Ryukyus, 理学部, 教授 (20045016)
RICHMOND Robert H. Associate Professor, Marine Laboratory, University of Guam
BIRKELAND Charles E. Professor, Marine Laboratory, University of Guam
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| Project Period (FY) |
1989 – 1991
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| Keywords | Invertebrate reproduction / Geographical variation / Fertilization / Corals / Sea urchins / Speciation / Nematocysts / Coral community |
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| Research Abstract |
The sexual reproduction of the coral Stylophora pistillata was studied in Okinawa. The coral released planulae synchronously one week after the full moon in April, May and June. The development of testes and ovaries began in January and in October, respectively. Planulae appeared in the coelenteron of polyps one month before being released. The planulae kept growing for one month in the coelenteron of the polyps. The reproductive pattern of Okinawan S. Distillate populations will be compared with that of Guam populations. (Yamazaio)
The four species of Indo-Pacific Echinometra were classified tentatively as A, B, C and D (Uehara, 1991). The failure of cross-fertilization and the differences in the gamete morphology show that Okinawan and Hawaiian species D are distinct species. Degree of gamete incompatibility between Okinawan D and Okinawan B was different from that between Okinawan D and Guam B. This suggests that Okinawan B and Guam B are in the process of speciation at fertilization
… More
level. Significant differences in the morphology of Echinothrix calamaris were found between Guam and Okinawan populations. A new species belonging to the genus Echinothrix was found in Guam. (Uehara)
The size and shape of a major type of nematocysts in tentacles were compared between two morphs of Galaxea fascicularis and between Stylophora pistillata and S. mordax. The results show that nematocyst morphology correlates with skeletal characters and that the two morphs of G. fascicularis and S. pistillata and S. mordax are, respectively, distinct species. (Hidaka)
A marked decrease in fertilization rate of coral eggs was observed when terrigenous run-off was present. There was a 95% reduction in planulae formation for Acropora eggs in waters collected from the reef near the Sesoko Island Bridge. The water was found to have 28.5 % salinity with a lateritic soil content of 1.28 grams/liter. The factors affecting fertilization need to be examined to determine what is causing the reduction. (Richmond)
Field survey of coral community/population structure, and field experiment for assessing the effect of consumers on biomass accumulation were carried out using cages at two depths (3 and 5 m deep) of three stations each in Guam and Okinawa. Significant difference was found both in coral community/population structure and in biomass accumulation among the stations. Correlations among the recorded parameters are now being analyzed. (Sakai and Birkeland) Less
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