Presentation Abstract
The Discovery Islands region is a major salmon migration corridor. Open net-pen salmon farms in the Discovery Islands and the Broughton Archipelago are a potential source of sea lice infestation and disease transfer to wild salmon, but the real risks and impacts remain unquantified. In 2017, 306 wild Chilko Lake sockeye smolts were captured and acoustic- tagged as they migrated from the lake. To investigate exposure time near salmon farms during their migration through the Discovery Islands region, we deployed acoustic receivers in Okisollo Channel, Hoskyn Channel, and two minor passes. Two of these acoustic receivers were placed within fish farm tenures. We calculated both travel time past individual farms and through the channels based on the time difference between first and last detections of individual fish; all of the farms in the Hoskyn and Okisollo Channel were fallowed in 2017 so exposure times presented here are baseline estimates. Seventy percent of tagged sockeye smolts used a migration route through the Discovery Islands that contained salmon farms. The median detection time near individual farms was low, ~4.5 minutes. Migration time through Hoskyn and Okisollo channels combined (7 salmon farm tenures; 25 km) averaged 31 hours, and 6 hours between the eastern and western receiver sub-arrays in Okisollo Channel (3 tenures; 4 km). Because DFO’s models of fish farm effluent concentrations near salmon farms indicate that a plume of particles is distributed over several dozen km, our travel time estimates can be used to calculate potential exposure times. In future, travel times can be assessed at operational farms and combined with models of effluent concentration to better assess the risk of wild salmon exposure to fish farms.
Session Title
The Salish Sea Marine Survival Project: Understanding Salmon Survival
Keywords
Sockeye salmon, Telemetry, Salmon farms, Salmon migration
Conference Track
SSE11: Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)
Document Type
Event
SSEC Identifier
SSE11-670
Start Date
5-4-2018 2:15 PM
End Date
5-4-2018 2:30 PM
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Salmonidae--Monitoring--Discovery Islands (B.C.); Salmonidae--Migration--Discovery Islands (B.C.); Fishes--Diseases--Discovery Islands (B.C.); Fishes--Parasites--Discovery Islands (B.C.); Fisheries--Environmental aspects--Discovery Islands (B.C.); Fish tagging--Discovery Islands (B.C.)
Geographic Coverage
Discovery Islands (B.C.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Included in
Fresh Water Studies Commons, Marine Biology Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons
Exposure time of juvenile sockeye salmon to Discovery Islands salmon farms
The Discovery Islands region is a major salmon migration corridor. Open net-pen salmon farms in the Discovery Islands and the Broughton Archipelago are a potential source of sea lice infestation and disease transfer to wild salmon, but the real risks and impacts remain unquantified. In 2017, 306 wild Chilko Lake sockeye smolts were captured and acoustic- tagged as they migrated from the lake. To investigate exposure time near salmon farms during their migration through the Discovery Islands region, we deployed acoustic receivers in Okisollo Channel, Hoskyn Channel, and two minor passes. Two of these acoustic receivers were placed within fish farm tenures. We calculated both travel time past individual farms and through the channels based on the time difference between first and last detections of individual fish; all of the farms in the Hoskyn and Okisollo Channel were fallowed in 2017 so exposure times presented here are baseline estimates. Seventy percent of tagged sockeye smolts used a migration route through the Discovery Islands that contained salmon farms. The median detection time near individual farms was low, ~4.5 minutes. Migration time through Hoskyn and Okisollo channels combined (7 salmon farm tenures; 25 km) averaged 31 hours, and 6 hours between the eastern and western receiver sub-arrays in Okisollo Channel (3 tenures; 4 km). Because DFO’s models of fish farm effluent concentrations near salmon farms indicate that a plume of particles is distributed over several dozen km, our travel time estimates can be used to calculate potential exposure times. In future, travel times can be assessed at operational farms and combined with models of effluent concentration to better assess the risk of wild salmon exposure to fish farms.
