Improving the efficiency of adaptive management methods in multiple fishways using environmental DNA

Area of Science:

• Aquatic Ecology
• Conservation Biology
• Environmental Monitoring

Background:

• Dams and weirs disrupt river connectivity, hindering migratory fish passage.
• Fishways are crucial for mitigating these impacts, but require effective post-installation management.
• Traditional fish catch surveys are burdensome and resource-intensive.

Purpose of the Study:

• To evaluate the efficacy of environmental DNA (eDNA) surveys for monitoring fish fauna in a fishway.
• To assess the application conditions and sampling frequency for eDNA in fishways.
• To compare eDNA survey results with traditional catch surveys for long-term adaptive management.

Main Methods:

• Utilized eDNA metabarcoding for fish fauna assessment from 2019 to 2022.
• Compared eDNA data with fish catch survey data from 2012 to 2022.
• Investigated eDNA implementation in a challenging fishway environment with limited flow space.

Main Results:

• Environmental DNA surveys successfully identified fish fauna in the fishway.
• eDNA surveys demonstrated potential for evaluating fishway contributions to biodiversity under specific conditions.
• A novel water sampling method for eDNA in fishways was introduced.

Conclusions:

• Environmental DNA surveys provide a viable, low-impact alternative to traditional fish monitoring in fishways.
• eDNA methods can support adaptive management strategies for fish passage facilities.
• Further research into optimal eDNA sampling strategies in varied fishway designs is warranted.