Reproduction, predation and recruitment of fisheries resources evaluated by environmental DNA

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H03031
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Kyoto University
• Principal Investigator: MASUDA Reiji 京都大学, フィールド科学教育研究センター, 教授 (60324662)
• Co-Investigator(Kenkyū-buntansha): 源 利文 神戸大学, 人間発達環境学研究科, 教授 (50450656)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: Environmental DNA / spawning / predation / recruitment / jack mackerel / Japanese anchovy / sea cucumber / black sea bream

Outline of Final Research Achievements

Environmental DNA technology for the quantification of marine species is developed targeting jack mackerel Trachurus japonicus, Japanese anchovy Engraulis japonicus, red-spotted grouper Epinephelus akaara, black sea bream Acanthopagrus shlegelii, and Japanese sea cucumber Apostichopus japonicus. Basic information such as effects of biomass, body size and interspecific mixing were also tested in tank experiments. High concentration of eDNA after the spawning was detected in jack mackerel and Japanese sea cucumber. Predation also induced eDNA peaks when Japanese anchovy, jack mackerel, and Japanese sea cucumber were preyed upon by their predators. Sampling in Tango Bay, off Kyoto, revealed that eDNA of black sea bream is detectable in 19 km offshore only in their spawning season (June) while it was detectable within 3 km offshore in other season. Environmental DNA is thus applicable to detect seasonal change of distribution in target species.

Free Research Field

Fisheries Ecology

Academic Significance and Societal Importance of the Research Achievements

一連の水槽実験により、環境DNAを用いた水圏生物の定量が十分に可能であること、また環境DNAを用いた繁殖や被食の検出も可能である反面、これらは対象生物を定量する上でのノイズともなることが示された。またクロダイの分布を調べたフィールド調査でも、従来の曳網調査と矛盾しない結果が得られ、従来の調査よりも高い精度で行うことができた。環境DNAに基づく定量に関わる諸問題を解決し、海域のマクロ生物を対象とした調査で環境DNAを応用する道を拓いたことは、十分な学術的意義を持つ。一連の成果はまた、水産資源管理や生態系保全といった分野へ直接応用が可能であり、社会的な意義もすこぶる大きい。