平成28（2016）年度　共同利用登録実施報告書

課題番号	28−共研−24	分野分類		統計数理研究所内分野分類		e
				主要研究分野分類		8
研究課題名	舞鶴湾におけるマアジの環境DNA分布に関する数値実験
フリガナ 代表者氏名	ユン ショクジン 尹 錫鎭		ローマ字		Yoon Seokjin
所属機関	北海道大学
所属部局	大学院水産科学研究院
職　　名	研究員

研究目的と成果の概要

Environmental DNA (eDNA) is originally shed from the bodies of organisms in the environment. Recent studies in streams and ponds have reported that the distribution and biomass of aquatic organisms can be estimated by detection and quantification of eDNA. In more open systems such as seas, it is not evident whether eDNA can represent the distribution and biomass of aquatic organisms because hydrodynamics is expected to affect eDNA distribution and concentration. Yamamoto et al. (2016) reported a significantly positive correlation between the biomass of Japanese jack mackerel (Trachurus japonicus) and their eDNA concentration in the surface layer of Maizuru Bay. However, there was an inconsistency between the fish biomass and their eDNA concentration especially in the bottom layer. The estuarine circulation could have effects on the eDNA distribution. In this study, therefore, using a three-dimensional tracer model, we analyzed the relationship between the fish biomass and their eDNA concentration. The eDNA was treated as a passive tracer including its release and decomposition. The release and decomposition rate were obtained from tank experiments. The eDNA concentration from a fish market was assumed as an extremely high value. There are predominantly outward flows in the surface layer, while landward flows in the bottom layer (i.e., typical estuarine circulation). In the surface layer, high eDNA concentration near shoreline due to high fish density is transported out of the bay. On the other hand, the intrusion of offshore water reduces eDNA concentration in the bottom layer. The modeled spatial variation in eDNA concentration shows a good agreement with the observed one. This indicates the eDNA can reflects the fish biomass in Maizuru bay.

In the Institute of Statistical Mathematics (ISM), the tracer model was integrated with a statistical model to estimate the fish biomass from the eDNA concentration. This co-research will be published in an international scientific journal and is expected to contribute to application of environmental DNA for quantitative monitoring of fish community and ecosystem assessment.

Yamamoto et al. (2016) Environmental DNA as a 'snapshot' of fish distribution: A case study of Japanese jack mackerel in Maizuru Bay, Sea of Japan. PLoS ONE 11(4): e0153291.