Geostatistical analysis of acoustic survey data on 0-group herring in a fjord

Abstract

An essentially pure aggregation of 0-group herring in Altafjord in northern Norway was acoustically surveyed on each of the first three days of December 1991. Measurements were made at 38 kHz during each survey and at 120 kHz during part of the second survey and all of the third survey. The data are expressed in terms of the area backscattering coefficient, applicable to the entire water column and averaged over intervals of 0.1 nautical mile. The spatial structure of the aggregation is characterized by the variogram. By means of geostatistics, estimates of abundance over the survey area are supplemented by estimates of variance.