Acoustic monitoring of wild fish interactions with aquaculture sites

Description

Some groups question the he sustainability of the BC salmon aquaculture industry due to concerns related to the potential risk posed by farmed salmon to wild salmon. Building on a previous project (P-14-01-001), this project aimed to understand the ecological interactions between wild and farmed salmon by determining the distribution and duration of juvenile salmon migration in the Discovery Islands and Johnstone Strait area, and by monitoring wild salmon interactions with aquaculture facilities.

The project monitored the activity of wild fish in the direct vicinity of aquaculture sites as well as wild salmon migration in Okisollo channel, performed fishing experiments and completed detailed analyses of the collected acoustic data. The results from this project help address critical uncertainties with respect to:

1. salmon behavior in their early marine life
2. disease transfer and interactions between wild and farm salmon
3. assessing the cumulative impacts of multiple stressors on Fraser River Sockeye Salmon productivity.

This project monitored the migratory pathways of wild salmon and the duration of their residency in the vicinity of fish farms. Estimating the prevalence of pathogens and diseases within wild and farmed populations, along with the overall physiological well-being and the health of wild populations can inform risk-assessment analyses of microbe transfer between farmed and wild hosts.

Findings

Acoustic systems can be successfully used to monitor, in near real-time, populations of juvenile wild salmon in areas utilized by the aquaculture industry. Additionally, imaging sonars can be used to monitor wild fish interactions with aquaculture facilities. These systems provide detailed data on the migration timing, duration, and dynamics of wild salmon populations.

Juvenile salmon behaviour near aquaculture sites varied in relation to both the diurnal and tidal cycles, as well as fish size. The number of juvenile salmon schools interacting with fish farms from May to August was documented, allowing to infer disease transfer potential. Results also provided detailed population monitoring in the Okisollo channel from which salmon productivity can be estimated. Data collected as part of this project are needed to assess the sustainability, and inform mitigation measures if needed, of the aquaculture industry around the Discovery Islands in BC.

Program name

Aquaculture Collaborative Research and Development Program (ACRDP)

Years

2017 – 2018

Principal investigator

Stéphane Gauthier, Research Scientist, Fisheries and Oceans Canada, Institute of Ocean Sciences, Pacific Region
Email: Stephane.Gauthier@dfo-mpo.gc.ca

Team member(s)

• Stewart Johnson, Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region
• Chrys Neville, Biologist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region
• Marc Trudel, Research Scientist, Fisheries and Oceans Canada, St. Andrews Biological Station, Maritimes Region

Collaborator(s)

• Barry Milligan, Fish Health Director and Veterinarian, Cermaq Canada Ltd.
• Sharon DeDominicis, Director, Marine Harvest Canada Limited