| Co-Investigator(Kenkyū-buntansha) |
OGAWA Kazuo The University of Tokyo, Graduate Schoo| of Agricultural and Life Science, Professor, 農学生命科学研究科, 教授 (20092174)
KANEKO Toyoji The University of Tokyo, Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (70221190)
NISHIDA Mutsumi The University of Tokyo, Ocean Research Institute, Professor, 海洋研究所, 教授 (90136896)
AOYAMA Jun The University of Tokyo, Ocean Research, Assistant Professor, 海洋研究所, 助手
OTAKE Tsuguo Mie University, Faculty of Biorecources, Professor, 生物資源学部, 教授 (20160525)
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| Research Abstract |
We made expeditions to a total of 17 countries for 575 days during the 1999 - 2001 fiscal years and Obtained the following results.
1. Migratory Behavior ; Based on the 5-year survey of glass eel recruitment to the Poigar River estuary on Sulawesi Island, we found that three anguillid species, in order of abundance, Anguilla celebesensis, A. marmorata, and A. bicolor pacifica occurred almost year-round. Otolith microstructure analysis showed that the spawning season of A. celebesensis and A. marmorata was year-round. From the survey in Iceland, we found that the Atlantic eel species, A. anguilla, A. rostrata, recruited to the Icelandic coast, with A. anguilla (95 %) being much more abundant than A. rostrata (5 %). The season of glass eel recruitment in Iceland was limited to around new moon in May and June, and downstream migration of silver eels occurred October to December.
2 Taxonomy and Phylogeny : Revision of the 18 species and subspecies of the genus Anguilla was made on specimens collected worldwide. As a result of morphological and molecular analyzes, we concluded that anguillid eels should be classified into 15 species. We also obtained a molecular phylogenetic tree for these 15 anguillid species.
3. Cevolution of parasites : Surveys on the monogenean Pseudodactylogyrus on the gills of Anguilla spp. found eight species, including six new ones, on four species of Anguilla distributed in the Far East, Papua New Guinea and Australia. These results show that speciation of these monogeneans occurred along with the adaptive radiation and speciation of the host.
During our research program in these three years, we published a total of 47 original papers. To review and synthesize all the results obtained in these studies, we organized an international symposium "Advances in Eel Biology" at the University of Tokyo in September 2001, and published a proceedings of 79 papers submitted to the symposium.
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