00000nam 2200000za 4500 9.806269 CaOODSP 20221107135844 cr ||||||||||| 150406s2000 oncdb ob f000 0 eng d CaOODSP eng eng fre n-cn--- Fs70-1/2000-152E-PDF Evaluation of utility of aerial overflight based estimates versus mark-recapture estimates of chinook salmon escapement to the Nicola River, B.C. [electronic resource] / R.E. Bailey … [et al.]. Ottawa : Fisheries and Oceans Canada, 2000. 35 p. : fig., graphs, maps, tables. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/152 Includes bibliographic references (p. 18-19). Adult chinook salmon were surveyed in the Nicola River from a helicopter and the count data was examined to determine their statistical properties. Replicated counts were compared and variances estimated for reach counts using regressions and quartile approaches. Reach counts were highly repeatable. Expansions of peak counts indexed abundance well among years, however, when using the standard expansion factor, estimates were biased low for three of four years when compared to Petersen mark-recapture estimates. AUC (area-under-the curve) estimates of spawner-days described the spawner abundance in a more robust manner than peak counts. Apparent redd residence times were stable among years. Retrospective AUC estimates, calculated using observed spawner data and the mean apparent redd residence time, adequately estimated spawner abundances for all four years. While at this time, it is not definitively known what minimum number of overflights are required to produce scientifically defensible AUC escapement estimates, it is likely that four or more flights may be required on many systems. It is recommended that similar studies be conducted in other watersheds in order to examine: 1) the repeatability of aerial counts; 2) spatial and temporal variability in survey life; and 3) degree of bias associated with aerial overflight-based estimates. gccst Fisheries resources gccst Salt water fish gccst Fishing area gccst Fisheries management Bailey, Richard Edward. Canada. Department of Fisheries and Oceans. Canada. Canadian Stock Assessment Secretariat. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/152 (CaOODSP)9.507740 PDF 1.13 MB https://publications.gc.ca/collections/collection_2015/mpo-dfo/Fs70-1-2000-152-eng.pdf