Mechanisms of the outbreaks of moon jellyfish: the contribution of overwintering medusae

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14909
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Central Research Institute of Electric Power Industry
• Principal Investigator: Suzuki Kentaro 一般財団法人電力中央研究所, サステナブルシステム研究本部, 主任研究員 (60638005)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ミズクラゲ / 個体群動態 / 越冬 / 環境要因 / 淡水棲クラゲ

Outline of Final Research Achievements

To understand the mechanisms of the outbreaks of moon jellyfish, field observations, laboratory experiments, and statistical analysis were carried out in Maizuru and Ise Bays. In Maizuru Bay, where overwintering medusae show winter spawning, the amount of overwintering medusae was suggested to affect the population size of medusae next early summer through their winter spawnings. In Ise Bay, where overwintering medusae are absent, the index of pacific decadal oscillation was correlated to the asexual reproduction during their polyp stage, while river discharge showed correlation with the survival rate after their ephyra release until growing up to medusae stage. The author and collegues also compiled all available litereture pieces about freshwater jellyfish, which are expanding their distribution globally, into a database between 1880 and June 2023, and wrote an integrative review.

Free Research Field

海洋生物学

Academic Significance and Societal Importance of the Research Achievements

ミズクラゲの大発生時には，水産業や発電所で被害が生じるほか，生態系や物質循環に与える影響が懸念されている．そのため，「大発生メカニズムの解明」が望まれているが，フィールドデータを解析した研究例はほとんどない．本研究では，越冬親クラゲの有無が異なる2海域を対象に調査やデータ解析等を実施し，親クラゲの越冬や各種環境要因が個体群動態におよぼす影響を明らかにしており，「大発生メカニズムの解明」に大きく貢献するものである．また，知見の限られる淡水棲クラゲ類の既存知見に関するデータベースや総説は，今後の淡水棲クラゲ類研究の基盤となるものである．