Since 1999, the Moricetown Salmon Tagging Project has been conducted on the Bulkley River by the Wet’suwet’en Fisheries and Fisheries and Oceans Canada, with the inclusion of data collection for steelhead (Oncorhynchus mykiss) under assistance from the British Columbia Smithers Fisheries Office and the Pacific Salmon Foundation. This mark and recapture project has involved sampling by beach seine for tag application immediately downstream of Moricetown Canyon (i.e., referred to as “campground”) and re-sampling by dip net at the base of Moricetown Falls and fishway (i.e., referred to as “canyon”). In 2011, steelhead catch at both the campground (N=1,131) and at the canyon (N=2,896) were relatively good in comparison to the earlier years of this study, but somewhat lower than the previous year (i.e., 2010) as a result of fewer steelhead arriving and reduced sampling effort due to high river levels. In total, 2,896 steelhead were examined at the canyon, including 140 recaptures of the 931 steelhead tagged at the campground. The stratified abundance estimates for steelhead arriving at Moricetown with a 2.5% correction for tag loss were 18,199 (95% C.I. 13 692 – 22,707) using Maximum Likelihood Darroch and 18 770 using Schaefer methods. The stratified abundance estimates are provided to identify potential inaccuracies, bias and misleading precision of 19,149 (95% C.I. 16 709 – 22 725) using the pooled Petersen estimate for inter-annual comparisons of steelhead abundance in previous years. In general, the pooled Petersen estimate for steelhead abundance in 2011 appears to be in the lower range in comparison to previous years and is less than half and significantly lower than the highest and most precise estimate of steelhead arriving at Moricetown in 2010 (i.e., 41,140 with 95% C.I.: 38,058 – 44,934).
The appendices to this report can be found here.