Burman River Chinook Salmon Total Escapement Estimation Project, Year 1

Project Lead:

Roger Dunlop, Nuu-chah-nulth Tribal Council, Gold River, BC
Diana Dobson, DFO, Stock Assessment, Nanaimo, BC

Project Cost: $142,600 CAN $110,829 US

This project is intended to provide an accurate and precise estimate of escapement and sex/age/origin for Burman River Chinook. Previous efforts in the Burman River (Dunlop 2007, Taylor and Dunlop 2008, Dunlop 2009) attempted to validate the area-under-the-curve index (AUC index) method by comparison with mark re-sight estimates. Two problems were identified in those programs: 1) immediate removal of carcasses from the river by predators made it impossible to properly estimate tag loss, and more importantly; 2) without physically recapturing carcasses and live fish it is not possible to demonstrate the absence of sampling bias. SSC reviewers recommended changing the primary project method to a two event Petersen estimate. We intend to compare the results obtained from the Petersen estimate with the normative, DFO funded, area-under-the-curve index (AUC index).

The objectives of the project are to:

  • Estimate the total escapement of age 3.0 and older Chinook salmon in the Burman River to the data standard (CV <15%, on average) using a two-event Petersen mark-recapture experiment.
  • Estimate the proportions of age > 0.3 Chinook by age, sex, size and origin (hatchery & wild) with the a 95% probability of detecting a 5 % change in the largest component between years.
  • Compare the escapement estimate result to the DFO funded AUC index result.