The Yukon River system encompasses a drainage area of approximately 854,000 km2 and contributes to important aboriginal, subsistence and commercial fisheries in the U.S. and Canada. Approximately 50% of Chinook salmon entering the Yukon River from the Bering Sea is typically destined for spawning grounds in Canada (Eiler et al. 2004, 2006). Chinook salmon that spawn in Canada have contributed up to 67% of the total U.S. commercial and subsistence fisheries in the Yukon River system (Templin et al. 2005; cited in Daum and Flannery 2009) .

Canadian and U.S. fishery managers of the Yukon River Joint Technical Committee (JTC) as well as members of the Yukon River Panel (YRP) recognize that obtaining accurate estimates of abundance is required for the management of Yukon River Chinook stocks. Quantified Chinook escapements along with biological information are important for post-season run reconstruction, pre-season run forecasts and the establishment of biologically based escapement goals. In addition, the accurate enumeration of genetically distinct stocks, coupled with a representative genetic stock identification (GSI) sampling program can be used to obtain independent above border as well as stock specific Chinook escapement estimates1 .

The Teslin River system has been identified as a potential Conservation Unit under the Fisheries and Oceans Canada (DFO) Wild Salmon Policy (DFO 2007). One of the long term goals of the Wild Salmon Policy is the establishment of biologically based escapement goals for all species of salmon within designated conservation units. A sufficiently long time series data set of salmon escapements coupled with stock recruitment modelling is the primary method for the establishment of biologically based escapement goals. Currently, there is no other in-season monitoring specific to Teslin River Chinook. Based on current data the Teslin system is the largest single tributary contributor to upper Yukon River Chinook production.

Teslin River origin Chinook have been an important contributor to aboriginal fisheries in the upper Yukon watershed and are of particular importance to the Teslin Tlingit First Nation. Monitoring of Teslin River Chinook will assist in achieving long term management and escapement objectives for the Teslin Tlingit Council (TTC). Of the five species of salmon entering the Yukon River, adult Chinook salmon travel the farthest upstream and have been documented at the furthest headwaters of the Teslin system in the McNeil River, 3,300 km from the river mouth (Mercer & Eiler 2004).