Presentation Information
[O12-P57]Fish fauna survey of rivers in Ishikawa Prefecture using environmental DNA through a high school student network
*Yu Hisada1, Takenori Taniguchi1, Kouki Wada1, Yuito Komai1, Mai Hayashi1, Maho Hoshiba1, Issei Taguchi1, Kazuki Sakamoto1, Tomoki Hoshiba1, Koutarou Kannoki1, Rikuto Nakamura1 (1. Ishikawa Prefectural Nanao High School SSC)
Keywords:
environmental DNA,fish fauna,high school student network,Noto Peninsula Earthquake,Crested Ibis,biodiversity
[Motivation and Objectives]
In Ishikawa Prefecture, no large-scale comprehensive survey of river fish fauna has been conducted since 1996. Over the past 30 years, it is expected that the fish fauna has undergone significant changes due to complex factors such as river channelization, the introduction of invasive species like largemouth bass, and rising water temperatures associated with global climate change.
The purpose of this study is to re-survey the current fish fauna using "environmental DNA (eDNA) technology," an efficient alternative to traditional capture-based methods, through a collaborative network of high school students. Furthermore, this research plays a critical role in long-term monitoring of ecological transitions following major natural disasters, specifically the 2024 Noto Peninsula Earthquake and the heavy rain event in September 2024. Additionally, to support the reintroduction of the Crested Ibis (Nipponia nippon) planned for 2026, we aimed to gather baseline data on the habitat of loaches and other key prey species to assess the sustainability of the "Satoyama" environment.
[Methods and Data Analysis]
Nanao High School began surveying the fish fauna of the Noto region using eDNA in 2023. To expand this into a prefecture-wide initiative, we strengthened cooperation with other schools, leading to the establishment of the "Ishikawa High School eDNA Lab-Net" in 2025, consisting of 10 high schools. This network covers the Noto, Kanazawa, and Kaga regions, enabling a simultaneous and broad-scale survey system.
The survey followed standard protocols established by the Ministry of the Environment and the eDNA Society. After filtering water samples and extracting DNA, we performed "species-specific PCR analysis" focusing on loaches (essential prey for the Crested Ibis) and ayu (sweetfish), which are vital local fishery resources. In collaboration with the Environmental Pollution Research Center Co., Ltd., we also conducted comprehensive "MiFish metabarcoding analysis" using next-generation sequencing to identify all fish species present. The number of survey sites expanded from 50 in Central Noto (2023) to 34 in Outer Noto (2024, scaled down due to disasters), and finally to 168 sites across the entire prefecture in 2025.
[Results]
The integrated analysis of the 2023 and 2024 data yielded the following findings. Species-specific analysis confirmed the presence of loaches in 31 new locations not documented in previous data, suggesting that a rich food supply for the Crested Ibis is maintained across the Noto Peninsula.
The metabarcoding results detected 66 species in 2023 and 40 species in 2024. Compared to the 1996 capture survey, 19 new species were identified, demonstrating the high sensitivity of eDNA technology. Notably, several rare species listed in the Ministry of the Environment's Red Data Book (RDB), such as Lethenteron reissneri, Oryzias latipes, and Anguilla japonica, were detected, revealing that Ishikawa’s rivers still maintain high biodiversity. Conversely, the widespread detection of invasive species like largemouth bass, bluegill, and Paramisgurnus dabryanus highlighted the ongoing pressure on native fish fauna.
[Conclusion and Future Challenges]
Through this study, high school students acquired advanced biotechnological skills and enhanced their scientific inquiry capabilities by visualizing their local environment. The extensive dataset obtained serves as a vital "baseline" for evaluating how river ecosystems recover and transition after large-scale disturbances like earthquakes and floods.
Moving forward, we plan to conduct a detailed biodiversity assessment by integrating our findings with meteorological and GIS data. We also aim to propose policies for sustainable Satoyama management to local governments. By solidifying this continuous monitoring system through the high school network, we hope that the youth involved will become the driving force for the future restoration and development of Ishikawa Prefecture.
In Ishikawa Prefecture, no large-scale comprehensive survey of river fish fauna has been conducted since 1996. Over the past 30 years, it is expected that the fish fauna has undergone significant changes due to complex factors such as river channelization, the introduction of invasive species like largemouth bass, and rising water temperatures associated with global climate change.
The purpose of this study is to re-survey the current fish fauna using "environmental DNA (eDNA) technology," an efficient alternative to traditional capture-based methods, through a collaborative network of high school students. Furthermore, this research plays a critical role in long-term monitoring of ecological transitions following major natural disasters, specifically the 2024 Noto Peninsula Earthquake and the heavy rain event in September 2024. Additionally, to support the reintroduction of the Crested Ibis (Nipponia nippon) planned for 2026, we aimed to gather baseline data on the habitat of loaches and other key prey species to assess the sustainability of the "Satoyama" environment.
[Methods and Data Analysis]
Nanao High School began surveying the fish fauna of the Noto region using eDNA in 2023. To expand this into a prefecture-wide initiative, we strengthened cooperation with other schools, leading to the establishment of the "Ishikawa High School eDNA Lab-Net" in 2025, consisting of 10 high schools. This network covers the Noto, Kanazawa, and Kaga regions, enabling a simultaneous and broad-scale survey system.
The survey followed standard protocols established by the Ministry of the Environment and the eDNA Society. After filtering water samples and extracting DNA, we performed "species-specific PCR analysis" focusing on loaches (essential prey for the Crested Ibis) and ayu (sweetfish), which are vital local fishery resources. In collaboration with the Environmental Pollution Research Center Co., Ltd., we also conducted comprehensive "MiFish metabarcoding analysis" using next-generation sequencing to identify all fish species present. The number of survey sites expanded from 50 in Central Noto (2023) to 34 in Outer Noto (2024, scaled down due to disasters), and finally to 168 sites across the entire prefecture in 2025.
[Results]
The integrated analysis of the 2023 and 2024 data yielded the following findings. Species-specific analysis confirmed the presence of loaches in 31 new locations not documented in previous data, suggesting that a rich food supply for the Crested Ibis is maintained across the Noto Peninsula.
The metabarcoding results detected 66 species in 2023 and 40 species in 2024. Compared to the 1996 capture survey, 19 new species were identified, demonstrating the high sensitivity of eDNA technology. Notably, several rare species listed in the Ministry of the Environment's Red Data Book (RDB), such as Lethenteron reissneri, Oryzias latipes, and Anguilla japonica, were detected, revealing that Ishikawa’s rivers still maintain high biodiversity. Conversely, the widespread detection of invasive species like largemouth bass, bluegill, and Paramisgurnus dabryanus highlighted the ongoing pressure on native fish fauna.
[Conclusion and Future Challenges]
Through this study, high school students acquired advanced biotechnological skills and enhanced their scientific inquiry capabilities by visualizing their local environment. The extensive dataset obtained serves as a vital "baseline" for evaluating how river ecosystems recover and transition after large-scale disturbances like earthquakes and floods.
Moving forward, we plan to conduct a detailed biodiversity assessment by integrating our findings with meteorological and GIS data. We also aim to propose policies for sustainable Satoyama management to local governments. By solidifying this continuous monitoring system through the high school network, we hope that the youth involved will become the driving force for the future restoration and development of Ishikawa Prefecture.