2019 Fiscal Year Research-status Report
A Socio-Ecological Approach to Restoring River Connectivity and Rewilding Salmon as Keystone Species in the Kushiro River Watershed, Eastern Hokkaido, Japan
| Project/Area Number |
17K00699
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| Research Institution | Sophia University |
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Principal Investigator |
伊藤 毅 上智大学, 国際教養学部, 准教授 (10646863)
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| Co-Investigator(Kenkyū-buntansha) |
渡邉 剛弘 上智大学, 国際教養学部, 准教授 (50439337)
北島 義和 釧路公立大学, 経済学部, 准教授 (70782952)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Keywords | Ecology and Society / Salmon ecology / Social Institutions / Kushiro River |
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| Outline of Annual Research Achievements |
In the third year, we focused on understanding social-ecological relations through a lens of salmon reproduction by means of hatcheries in Hokkaido. In Japan, salmon hatcheries were established to manage salmon stocks so as to reduce the risk of scarcity and satisfy the market demand for salmon. Building on previous studies, however, our research has shown that salmon hatcheries, characterized by human action to alter our physical environments to our liking, have had far reaching impacts―both social and ecological. We examined how salmon propagation through hatcheries has developed in Hokkaido since 1888 and particularly explored how it shaped the local salmon ecology in the Kushiro river basin. Our research suggests that the salmon capture sites in the Kushiro river system have gradually been moved downstream to maximize salmon catch while reducing the space for salmon in the Kushiro river system, preventing salmon from spawning naturally in the tributaries and streams in the wetland area. When capturing sites were located upstream, returning salmon had a much wider space in the wetland and connected tributaries to spawn naturally before being caught by the urai traps. Moving the capturing site closer to the river mouth meant that salmon could neither receive the benefits bestowed by the wetland nor deliver nutrients from the sea to the upstream forests.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Based on our research findings, we wrote a peer-reviewed journal article entitled “Protecting Natural Reproduction of Salmon and Restoring Wetlands in Kushiro, Hokkaido: A Prolegomenon.” It will be published on Wetland Research in 2020. We see this publication as a positive sign that our research is moving forward and making a significant progress towards the overall goal. Furthermore, we wrote a peer-reviewed book chapter on teaching social-ecological relations through fieldwork entitled 「上智大学の取り組み：フィールドから学ぶ人間社会と自然環境の相互関係 」. It was published in February 2020.
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| Strategy for Future Research Activity |
In the final year, we are concluding our three-year research project. For the most part, our research has progressed as we planned. However, the outbreak and spread of COVID-19 in early 2020 prevented us from conducting fieldwork. Under the extraordinary situation, the research project has been extended for one year. Our research will detail the ways in which human action to increase salmon stocks shapes the space and time of salmon’s life-making that connects not only forests and seas but also territories and territorial seas divided and controlled by various national and local governments. In the final year 2020-21, we plan to complete the fieldwork in Hokkaido and the Pacific Northwest. Given the uncertainty of the COVID-19 situation, we take precautious measures in planning fieldwork.
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| Causes of Carryover |
The outbreak and spread of COVID-19 have canceled and delayed our research plans in 2020. We plan to implement the planned activities in FY 2020.
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