2025-12-11 東京大学大気海洋研究所
マイワシの環境DNAが深海に隔離されるメカニズム
＜関連情報＞
- https://www.aori.u-tokyo.ac.jp/research/news/2025/20251211.html
- https://www.aori.u-tokyo.ac.jp/research/news/2025/files/20251211_summary.pdf
- https://www.sciencedirect.com/science/article/pii/S0079661125002137
深海に生息する小型外洋魚の環境DNA Environmental DNA of small pelagic fish in the deep ocean
Zeshu Yu, Marty Kwok-Shing Wong, Jun Inoue, Yuan Lin, Itsuka Yabe, Tomihiko Higuchi, Susumu Hyodo, Sachihiko Itoh, Yuichiro Nishibe, Hajime Obata, Shin-ichi Ito
Progress in Oceanography Available online: 20 November 2025
DOI:https://doi.org/10.1016/j.pocean.2025.103625
Highlights
- Vertical distribution of eDNA for two small pelagic fish species was investigated in Northwest Pacific.
- Lower water temperature in deep ocean favors the existence of DP-eDNA.
- Higher chlorophyll-a concentration in the habitable range increases sardine DP-eDNA.
- Estimated eDNA sinking velocity is comparable to that observed in particulate organic carbon.
Abstract
Environmental DNA (eDNA) method has been widely used worldwide for ecological surveys of fish. However, the accuracy of eDNA in deducing fish distribution, especially vertical distribution in the open ocean, is uncertain due to insufficient observation. This paper observed and studied the eDNA vertical distribution in the open ocean, focusing on two economically important small pelagic fishes, Sardinops melanostictus and Engraulis japonicus (here after sardine and anchovy respectively) in the Northwest Pacific. From the uninhabitable deep ocean layers, their eDNA was detected and we referred them as “DP-eDNA”, which suggests eDNA from pelagic fish may exist far below where they live. Higher DP-eDNA ratios were observed for sardine and anchovy when seawater temperature was lower, likely due to slower degradation. The sardine DP-eDNA ratio was higher when chlorophyll-a concentration (and turbidity) was higher, which may suggest that the fish eDNA could be attached to phytoplankton-produced particles that enhanced the eDNA sinking. Meanwhile, for anchovy, the DP-eDNA ratio was lower when dissolved oxygen concentrations were higher, which may be caused by a faster microbial-related degradation. The eDNA sinking velocity was estimated to be 39 − 255 m day−1 (sardine) and 36 − 241 m day−1 (anchovy), values comparable to the observation data in particulate organic matter (POM), although the DP-eDNA formation mechanism could be more complex than simple sinking. This study recorded the downward vertical movement of DNA in open ocean and its environmental-dependent characteristics, and our results deepen the considerations that should be taken when eDNA is used to deduce the vertical distribution of fish in the open ocean.
