Acoustic estimates of zooplankton biomass and distribution: application ofcanonical correlation to scaling of multifrequency acoustic data

A technique is presented that can be used to scale multifrequency acoustic data to estimates of wet weight biomass from concurrently collected zooplan kton samples. The technique uses canonical correlation to identify those ta xa that correlate with the acoustic data. Canoncial correlation is then use d to compute scaling coefficients that can be used to convert transect data to biomass equivalents for the correlating taxa. Examples are offered to i llustrate how the technique can identify euphausiid aggregates, pteropods, and larval fish. The technique can discriminate between taxa with gas bladd ers, taxa with shells, and fluid-filled taxa. It also has the advantage of quantifying the correlation between the target taxa and acoustic data, thus allowing the researcher to judge the usefulness of the acoustic data in ch aracterizing the distribution and density of the zooplankton taxa.