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クロマグロ仔魚の輸送過程と初期生残に影響を及ぼす環境要因に関する数値計算学的研究

影响蓝鳍金枪鱼幼体运输过程及早期存活的环境因素数值研究

基本信息

批准号：
18880008
负责人：
北川貴士
金额：
$ 1.34万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Young Scientists (Start-up)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

超高解像度海洋大循環モデルの流動場・水温データを用いて、産卵海域を石垣島南部、琉球列島北部、沖縄本島・南大東島南部、奄美東部に区分して粒子追跡実験を行った。石垣島南部海域の仔魚は、15日目までは産卵海域に滞留するが、その後は30%程度が黒潮に取り込まれ、25日後には日本沿岸に到達した。これは、この海域での産卵が、仔魚期における滞留と、豊富な餌が期待できる日本沿岸への低いエネルギーコストでの輸送を可能にしていることを示している。一方、黒潮流路付近の琉球列島北部海域では、少なくとも産卵後15日には日本沿岸の低水温海域に到達するが、仔魚が経験する水温変化は他の海域と比較して大きく、最大で2.5℃にも達した。この場合には前期仔魚期間を通じて、適水温海域に留まることは難しく、高い生残は期待できない。沖縄本島・南大東島南部海域では、25日齢までに日本沿岸に到達することはなく当該海域に留まる可能性が高い。稚魚に変態する段階で急速な成長を伴うことから、日本沿岸と比較して生物生産性が低い産卵海域に留まると、仔魚にとって高水温による速い成長は期待できるものの、餌不足により稚魚期に成長できなくなる可能性がある。奄美東部海域では、沿岸に輸送される仔魚の割合は沖縄南部での黒潮分枝流の発達程度に依存し、分枝流の流量が少ない場合には産卵場に留まるが、多い場合には約25日で生残に不適な黒潮続流域まで輸送されてしまう可能性が高いことが分かった。以上から、産卵海域でも海域によっては仔魚が輸送過程で経験する水温は大きく異なり、高水温海域に一定期間滞留した後に素早く沿岸へ輸送される可能性の高い石垣島南部海域での産卵が、生残に最適と考えられた。

Ultra-high-resolution ocean circulation flow field, water temperature control, spawning sea areas, southern Ishigaki Island, northern Ryukyu Islands, Okinawa Main Island, southern Minami-Daito Island, and eastern Amami are divided into particle tracing areas. The larvae are caught in the southern sea of Ishigaki Island, the spawning sea area is stagnant on the 15th, the 30% black tide is taken out after the 15th day, and the Japanese coast is reached after the 25th.これは, このsea area での spawning が, larval stage における stay と, 豊富なbaiting が look forward to できる日This coast is a low-rise and low-rise river that can be transported along the coast. On the one hand, the Kuro Current flows in the northern waters of the Ryukyu Islands, and on the 15th day after spawning, in the low-temperature waters off the coast of Japan. The water temperature of the larvae has changed, the water temperature has changed, the sea area has changed, the comparison has reached a large level, and the maximum has reached 2.5℃. It is a good place to stay in the early larvae period, it is difficult to stay in the sea with suitable water temperature, and it is difficult to stay in the sea area with high water temperature. The sea area south of Okinawa Main Island and Minami Daito Island will reach the sea area along the coast of Japan on the 25th. The possibility of staying in this sea area is high. Juvenile fish are in the stage of rapid growth and the growth rate is high, and the coast of Japan is comparatively low in biological productivity, and the spawning sea area is low in spawning sea area. The larvae are expected to grow quickly due to high water temperature, and the possibility of growth during the juvenile stage due to insufficient bait is the same. In the eastern sea area of Amami, there is no need to cut and combine the larvae that can be transported along the coast. In the southern part of Okinawa, there is a high degree of dependence on the Kuroshio branch stream, and the flow of the branch stream is small. The spawning ground is maintained, and the spawning grounds are maintained for about 25 days. Above, the spawning sea area and the larvae transport process are the same, and the water temperature is high and the water temperature is high, and the high water temperature sea area is a certain period. The probability of being detained in the period is high, and the possibility of transporting along the coast is high. The southern sea area of Ishigaki Island is the most suitable for spawning and reproduction, and the examination is the best.