| Project/Area Number |
19380114
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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 | Nagasaki University |
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Principal Investigator |
KAWABE Ryo Nagasaki University, 環東シナ海海洋環境資源研究センター, 准教授 (80380830)
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| Co-Investigator(Kenkyū-buntansha) |
KITAGAWA Takashi 東京大学, 新領域創成科学研究科, 助教 (50431804)
中田 英昭 長崎大学, 水産学部, 教授 (60114584)
石坂 丞二 長崎大学, 水産学部, 教授 (40304969)
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| Co-Investigator(Renkei-kenkyūsha) |
NAKATA Hideaki 長崎大学, 水産学部, 教授 (60114584)
ISHIZAKA Joji 名古屋大学, 地球水循環研究センター, 教授 (40304969)
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| Project Period (FY) |
2007 – 2009
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| Project Status |
Completed (Fiscal Year 2009)
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| Budget Amount *help |
¥19,500,000 (Direct Cost: ¥15,000,000、Indirect Cost: ¥4,500,000)
Fiscal Year 2009: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2008: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
Fiscal Year 2007: ¥10,530,000 (Direct Cost: ¥8,100,000、Indirect Cost: ¥2,430,000)
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| Keywords | クロマグロ / 鉛直遊泳 / シイラ / データロガー / 漁場形成 / 水温構造 / 温暖化 / クロマグロ未成魚 / 地球温暖化 |
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| Research Abstract |
To clarify their vertical distribution of Pacific bluefin tuna (PBFT), Thunnus orientalis, and Dolphin fish (DF), Coryphaena hippurus, we obtained the data of swimming depth and temperature from data-loggers for PBFT in April, May and November 2007, and for DF in May, September and October 2007 in the East China Sea. With the developing vertical stratification in late May when sea surface temperature is over 20℃ in the northern part of the East China Sea, PBFT sifted the distribution from the surface to the bottom to just above the thermocline, although PBFT made vertical excursions to bottom layer in early May and November when vertical structure of water temperature was homogeneous. At the same time, DF which appeared in this area remained near the surface due to avoiding cooler water of <19 ℃. However, DF's data in September and October indicated that DF should extend the swimming depth in the surface mixed layer where longline hooks is set more, with rising temperature in the surface mixed layer and more intensify the thermal stratification. The change of their distributions in late spring will increase the chance that DF will encounter longline hooks. We suggest that for more efficient catch of the main target PBFT avoiding bycatch DF, the longlines should be set at the depth based on their vertical distributions related to their respective temperature preferences seasonal change of vertical temperature structure.
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