| A methodology combining acoustics and net tows was tested and evaluated on euphausiid biomass and distributions in two B.C. inlets adjoining the Strait of Georgia from 1991 to 1996. Better information concerning the reliability of seasonal and interannual variability of euphausiid stock size estimates as well as the within-time-period statistical reliability of these estimates was the goal of this thesis. Repeated surveys were conducted primarily in the spring and fall in both Jervis and Saanich Inlets, and monthly surveys were conducted in Jervis Inlet between June 1994-June 1995. Acoustic samples were the primary data source for biomass estimates, with net tows providing species composition and size-frequency distributions.;Transects provided closely-spaced acoustic sample points along lines. Estimation of total stock size from samples required point observations to be converted into maps, and maps to be converted to integrated biomass estimates for the survey area. Block averages estimated stock sizes from a mosaic of equally weighted sample averages integrated over the survey area. The geostatistical interpolation method of kriging estimated unknown points within an area based on a function of spatial autocovariance and unique weightings applied to neighbouring measurements. (Abstract shortened by UMI.). |
