Water Stewardship Information Sources
| Citation | Balke, JME, Tschaplinski, PJ, Crockford, SJ and Suther, G. 1998. River Otter predation on juvenile salmonids in winter: Preliminary report of the otter scat collection and diet analysis. In: Hogan, D.L., P.J. Tschaplinski, and S. Chatwin (Editors). B.C. Min. For., Res. Br., Victoria, B.C. Land Manage. Handb. No. 41. |
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| Organization | FLNRO |
| URL | https://www.for.gov.bc.ca/hfd/pubs/docs/Lmh/Lmh41.htm |
| Abstract/Description or Keywords | Several creeks in the Queen Charlotte Islands, British Columbia have been identified as sites where the rates of river otter (Lutra canadensis) predation on overwintering juvenile coho salmon (Oncorhynchus kisutch) and rainbow trout (O. mykiss) might be high. A study was undertaken in six watersheds on Graham and Moresby islands to determine the presence or absence of river otters, to assess the feasibility of collecting analyzable river otter scats in winter, and to identify river otter prey species from scat analysis. Over 500 river otter scats were collected from seven creeks during surveys in November 1992 and February 1993. The November sampling period corresponded with the end of salmon spawning runs and bones of adult salmonids were found in scats from all creeks and shorelines. In February, when spawning salmon were unavailable, the scats contained bones from salmonids as well as 19 other freshwater and marine fish species/genera. River otters using these creeks were also foraging in the ocean. Juvenile salmonid bones were found in the scats from four creeks in November and from all creeks or adjacent shorelines in February. Fresh samples of at least 97 scats, collected in February from four river systems, contained 347 salmonid otoliths. Ninety-three percent of these otoliths were between 1.5 and 2.5 mm long. This study confirmed that river otters use these river systems in the Queen Charlottes during winter and that, despite the adverse weather conditions, river otter scats can be readily collected and the prey species determined. To further quantify the impact of river otter predation on overwintering slamonids, a more detailed study of river otter populations in these watersheds would be required. |
| Information Type | abstract |
| Regional Watershed | Coast Region |
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| Project status | complete |
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