1997 Fiscal Year Final Research Report Summary
Functional stock structure related to spawning of the Japanese flounder in the Sea of Japan
| Project/Area Number |
08456096
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
TANAKA Masaru KYOTO UNIVERSITY Graduate School of Agriculture, Professor, 農学研究科, 教授 (20155170)
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| Co-Investigator(Kenkyū-buntansha) |
TOYOHARA Haruhiko KYOTO UNIVERSITY Graduate School of Agriculture Associate Prof., 農学研究科, 助教授 (90183079)
ARAI Nobuaki KYOTO UNIVERSITY Graduate School of Agriculture Assistant Prof., 農学研究科, 助手 (20252497)
KINOSHITA Izumi KYOTO UNIVERSITY Faculty of Agriculture Assistant Prof., 農学部, 助手 (60225000)
SEIKAI Tadahisa KYOTO UNIVERSITY Faculty of Agriculture Assistant Prof., 農学部, 助手 (10144338)
NISHIDA Mutsumi Fukui Prefectural University, Department of Biosciences Professor, 生物資源学部, 教授 (90136896)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Japanese flounder / The Japan Sea / genetic stock structure / geographical variation / fin-fay number / mitochondrial DNA |
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| Research Abstract |
The Japanese flounder (Paralichthys olivaceus) is one of the most important coastal fishes, commonly distributed in coastal waters of the northwestern Pacific. When we consider fisheries management and stock enhancemnet, the most important factor appears to understaned stock structure which works as a spawning unit. In the present study, we examined geographical variations in morphological, ecological and physiological characterisitcs and analyzed genetic stock structure of juvenile flounder which were collected from the entire area along the coast of the Japan Sea.
The results obtained are as follows.
1.Geographical variations in unmber of dorsal and anal fin rays were clear : lower in north and higher in south, and discontinuously separated by the Noto peninsula.
2.It was experimentaly confirmed that higher temperature at onset of metamorphosis increased the unbmer. Since average water temperature to which the wild larvae encountered in the sea is slightly higher in north, the above mentioned geographical variation seems to have a genetic background.
Daily growth of juveniles was higher in north than in south.
Nusleotide sequence in control region of mt-DNA was highly variable among juveniles collected from almost whole coastal area inclucing the Pacific.
5.Two major haplotypes were recognized, and proportion of the 2 types was not significantly different among most of sampling sites, however a skewed proportion was observed in Sado Isl. and Hokkaido.
6.The haplotype composition of about 200 adults collected in the Wakasa Bay area was examined to see difference by age and season, showing that a part of the population would move toward west from this area in relation to spawning.
These results suggest that a frequent gene flow commonly occur by larval transport and adult migration, but there may be different spawning stocks having different eco-physiological and morphological features along the coast of the Japan Sea.
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