Preliminary results - Part 1

I spent about 10-12 hours today working with acoustic data. I have something interesting to share. On Monday we collected eight zooplankton samples with a 63 micron mesh net. The sites ranged in depth from 20 - 90 m.  Each tow was from 25 m to the surface, except for the shallowest station which was 18 m to the surface. I arranged the samples from shallow to deep (left to right) in the photograph.

It may be hard to see, but there was more zooplankton over shallow water.  The acoustic data shows a similar pattern. I divided our 2 transects into 20 or so 100 m intervals and estimated the volume backscattering strength (abbreviated Sv) in the top 25 m (actually 3-25 m) along each interval with the the 5 frequencies we're exploring. Each frequency had higher Svs over shallower water than deeper water. The data seem to make some sense! But note the point I labeled as goofy in the plot.