High‐frequency acoustic scattering is well‐suited to the synoptic investigation of marine organisms that inhabit the water‐column, such as zooplankton and fish. However, the scattering characteristics of the organisms can be highly complex, and one must look for ways to distinguish one type of organism from another when interpreting the received echoes. From an acoustic scattering perspective, zooplankton generally fall into one of three categories: gas‐bearing, fluid‐like, or elastic‐shelled. Scattering models, of different levels of sophistication are available for all three types of zooplankton. Gas‐bearing zooplankton, unlike the other zooplankton categories, have a strong scattering resonance, which can be exploited for their identification. Scattering from gas‐bearing zooplankton at frequencies close to the resonance frequency is much stronger than scattering from other zooplankton. Thus, in this frequency region, acoustic scatter from a small number of gas‐bearing zooplankton can overwhelm that from a far larger number of fluid‐like or elastic‐shelled zooplankton. A series of zooplankton surveys of the Gulf of Maine has recently been completed in which a multi‐frequency towed instrument platform, BIOMAPER‐II, was employed. The strong scattering resonance of gas‐bearing zooplankton, together with scattering models and ground‐truthing, was exploited in order to determine regions with high densities of gas‐bearing zooplankton.