| Project/Area Number |
17510199
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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 |
Resource conservation science
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| Research Institution | Nihon University |
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Principal Investigator |
TANIUCHI Toru Nihon University, College of Bioresource Sciences, Professor, 生物資源科学部, 教授 (00012021)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Takahito Nihon University, College of Bioresource Sciences, Associate Professor, 生物資源科学部, 助教授 (60205383)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | deep-sea / chondrichthyans / Tokyo Submarine Canyon / Sea of Japan / life-history traits / by-catch / stable isotope ratio / feeding position / 深海性軟骨魚類 / ミツクリザメ / フトツノザメ / ツマリツノザメ / ドブカスベ / ガンギエイ / 遺伝子解析 / 東京湾海底谷 |
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| Research Abstract |
We conducted to elucidate biodiversity and life-history of deep-sea chondrichthyan fishes in two localities of Japanese waters, Tokyo Submarine Canyon and the Sea of Japan. We collected 31 species of chondrichthyans from Tokyo Submarine Canyon. Among them, we attempted to study age and growth of Deania calcea by using cross sectioned spine of the second dorsal spine and Mitsukurina owstoni by vertebral centra. The former species showed a relatively faster growth pattern while the latter resulted in the same growth pattern as the other deep-sea chondrichthyans, showing the maximum age of 25 year-old. We analyzed feeding position of 23 species of chondrichthyans using stable isotope ratios of δC^<15> and δN^<13>. The C-N map revealed that two species chimaeras and a skate species showed high δC^<15> and δN^<13>while 20 species of sharks ranged from relatively high to low δC15 and δN^<13>. These results implied that the former group of species belongs to benthic algae series as a primary
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production whereas the latter group stem from various spectra between benthic algae and phytoplankton series. We carried out life-history traits of a skate, Raja kuwantongensis collected from Niigata region in the Sea of Japan. Stomach contents analysis showed the skate eat crustaceans, fishes and molluscs in a due order. Shrimps were supposed to be the most important prey in this skate because they were found in stomachs of specimens of all sizes collected in every season. Important commercial species were also observed in stomachs, which may suggest that the skate has an impact on target species of commercial fisheries. Examination of vertebral centra showed that one ring was formed annually. Growth study revealed that the Maximum age is 12 year-old in males and 13-year-old in females in samples. Judging from the state of claspers and testes in males and ovaries and uteri in females, both sexes attain maturity at 500 mm in total length. Oviposition was supposed to extend a long period of the year. Less
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