Underlying theory#
This section contains information about the acoustic and spatial statistics theories underlying the computation implemented in Echopop.
The Acoustics basics page contains information about important acoustic quantities for deriving biological estimates in general.
The flow of computation in Echopop that combines acoustic data (in particular NASC) and biological data from trawls (detailed here) to derive biomass estimates is described across a few pages:
Biological estimates: derive number density from acoustic data
Stratification to obtain biomass density: derive biomass density by combining number density and animal length-weight information from trawl data
Kriging biomass density: perform kriging on biomass density (to be added)
Apportioning kriged biomass density: apportion kriged biomass density to estimate biomass for animals of different sexes, lengths, and ages
The other pages contains detailed information of spatial statistics used for kriging:
Kriging equations: equations of different kriging models
Semivariogram equations: equations of different semivariogram models