Reverberation structure has been observed from research platform FLIP with a narrowbeam, high‐resolution 87.5‐kHz echo sounder. The system resolution indicates that the backscattering can be resolved as discrete targets. Targets strengths and scatterer densities suggest that the scatterers are probably fish and possibly squid and siphonophores. Although zooplankton may be observed acoustically if there are sufficient animal densities, they will not be the dominant scatterers below the mixed layer for small insonified volumes. A midnight migration was observed that corresponded with the passage of rain squalls.