Water Stewardship Information Sources

Citation Madrone Environmental Services Ltd. 2015. Somenos basin coho salmon summer habitat assessment. Prepared for Somenos Marsh Wildlife Society.
Organization Somenos Marsh Wildlife Society
URL http://somenosmarsh.com/files/7014/2385/3376/Somenos_Basin_Coho_Salmon_Habitat_Assessment.pdf
Abstract/Description or Keywords During the summer of 2014, we investigated the summer distribution and movements of juvenile
Coho Salmon (Oncorhynchus kisutch), Steelhead (Oncorhynchus mykiss), and Cutthroat Trout
(Oncorhynchus clarkii) in the Somenos basin and monitored temperature and other
environmental variables to assess habitat suitability. We found that juvenile salmonids were
absent from Somenos Lake by at least July and did not appear to have returned to the lake by
the end of sampling in early November. Temperature was monitored by data loggers located in
Somenos Lake and its three tributaries: Bings Creek, Averill Creek, and Richards Creek.
Somenos Lake was also monitored daily by a team of volunteers who collected data on
temperature, water clarity, dissolved oxygen and atmospheric conditions at a lakeside station.
The Surface temperature of Somenos Lake was higher than 21ºC from the beginning of
monitoring in July to the middle of September. Only Pumpkinseed Sunfish (Lepomis gibbosus)
and Threespine Stickleback (Gasterosteus aculeatus) were found in Somenos Lake during
trapping in October and November. Tributary temperatures never exceeded 18ºC throughout
the monitoring period. Although temperatures in Richards Creek were suitable for juvenile
salmonids, none were observed during trapping events. During trapping in early October,
Juvenile Coho Salmon were caught in Averill Creek and Bings Creek and Cutthroat Trout in
Bings Creek.
Information Type report
Regional Watershed Vancouver Island South
Sub-watershed if known Cowichan, Somenos
Aquifer #
Project status complete
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