Estimation of jellyfish patch density and bay-scale abundance using aerial photography and numerical model

2015 Fiscal Year Final Research Report

• Project/Area Number: 25550014
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Ehime University
• Principal Investigator: Guo Xinyu 愛媛大学, 沿岸環境科学研究センター, 教授 (10322273)
• Co-Investigator(Kenkyū-buntansha): TAKEOKA Hidetaka 愛媛大学, 沿岸環境科学研究センター, 教授 (90116947) ; YOSHIE Naoki 愛媛大学, 沿岸環境科学研究センター, 講師 (50374640) ; FUJII Naoki 佐賀大学, 低平地沿岸海域研究センター, 助教 (10403859)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: ミズクラゲ / 集群 / 計量魚探探査機 / 水中カメラ

Outline of Final Research Achievements

To know bay-scale abundance of moon jellyfishes, spatial distribution and swimming features of individual jellyfish in its aggregations in Uwa Sea, we carried out a monitoring by a camera fixed at a highland and three times of ship-based observations using underwater camera and echo sounder. We found the presence of hollow structure in the vertical distribution of jellyfish density inside the aggregations that usually presents a spherical or zonal shape at sea surface. We also demonstrated a well matching of echo sounder based jellyfish density to that given by an underwater camera in all three field observations. Therefore, the echo sounder scanning over a bay is an efficient way for knowing the abundance of jellyfish in the bay and will serve as a good tool for understanding the formation mechanism of a hollow structure inside the aggregation of jellyfish that was also reported in the western coast of American recently.

Free Research Field

海洋物理学