Adjustments had to be made to compensate for deep-water backscatter attributed to anchovy but where few or no anchovy were sampled by daytime purse-seine sets. Biomass density was computed separately for backscatter shallower and deeper than 30m depth. In the shallow layer, backscatter was apportioned using proportions and lengths of all CPS present in the nearest purse-seine catches; deeper than 30 m, all CPS backscatter was apportioned using the lengths of anchovy in the nearest set that collected anchovy.
Adjustments had to be made to compensate for deep-water backscatter attributed to anchovy but where few or no anchovy were sampled by daytime purse-seine sets. Biomass density was computed separately for backscatter shallower and deeper than 30m depth. In the shallow layer, backscatter was apportioned using proportions and lengths of all CPS present in the nearest purse-seine catches; deeper than 30 m, all CPS backscatter was apportioned using the lengths of anchovy in the nearest set that collected anchovy.