Coho salmon (Oncorhynchus kisutch) are an important species for commercial, aboriginal, and recreational fisheries in British Columbia and have been declining significantly in numbers for much of the past two decades. The decline in numbers, estimated to be greater than 60%, has been attributed to changes in marine and freshwater environments, and to over-fishing, either in directed fisheries or incidental bycatch (Irvine, 2002). There has been restricted fishing of coho since 1998, but poor returns have continued, leading to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designation of endangered species in 2002. COSEWIC further recommended that the species be listed under the Species At Risk Act (SARA), but in 2006 the Minister of Environment made the decision to not protect coho under SARA based on ?uncertainties associated with changes in the marine environment and potential future socio-economic impacts on users associated with the uncertainty.?
Interior Fraser River Coho (IFC) are the northernmost population of Fraser River coho, ranging from Hell?s gate in the south (Fraser canyon) to the Northern reaches and tributaries of the Fraser River. IFC is a group composed of five sub-populations of coho existing in the Interior Fraser River watershed: Fraser canyon, Lower Thompson, South Thompson, North Thompson, and Upper Fraser (Interior Fraser Coho Recovery Team. 2006). The IFC population is genetically distinct from all other coho salmon, including those populations found in the lower Fraser River (below Hell?s Gate). The sub-population that is the focus of this report is Upper Fraser IFC that spawn in the Quesnel Lake watershed.
Upper Fraser River coho have traditionally accounted for a smaller percentage of the total IFC run, but this trend has begun to change in recent years. Table 1 shows escapement numbers for Upper Fraser River Coho in comparison to totals for the entire IFC run. As can be seen in this table, the proportion of the total Interior Fraser River run made up by the Upper Fraser population has changed dramatically, remaining highly stable at around 10.3 % through the seventies, beginning to fluctuate in the late eighties, and ranging in recent years from a low of 5.9 % in 1993 to a recent high of 20.2% in 2006.
The trend that emerges is that the IFC population may be becoming of greater significance in relation to other Fraser River stocks as these populations continue to vary in numbers. However, IFC in many regions have dropped both in numbers as well as in the number of streams they are found in (Interior Fraser Coho Recovery Team, 2006; Irvine & Bradford, 1999). Thus, it is important to monitor these stocks to ensure that they do not become extinct.
Holmes, Jordan, Holmes, Richard. 2008. Adult Coho Assessment of Tributaries of Quesnel Lake (WSC 160 Waterbody 00431QUES). Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2008MR338
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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