At Ocean Acre, the volume backscatter strengthS(z;f), 12–15.5 kHz, associated with the daytime deep scattering layer in the main thermocline region is due to backscattering from swimbladder fish. In the NDI model forS(z;f) developed previously for light‐sensitive layers, it is assumed that the number densityn(z) of “effective scatterers” is determined by a Gaussian distribution of “preferred” light intensity valuesItracked by the scatterers. thatIdecays with depth according to Lambert's law, and that the average backscatter cross section δ(z;f) is a constant, δ(f). This model is found to describe the daytime deep scatterer profileSonly ifIis replaced by an analogous “preferred” variableI′with an exponential decay rate approximately one‐tenth the extinction coefficient for light. Thus, some other environmental factor than light intensity primarily determines the shape of theS‐profile for this layer. Here a physical interpretation of the NDI′ model is developed by showing that (1) measured abundance profilesnb(z) of swimbladder fish in the daytime deep scattering layer are described by the NDI′ model and (2), the exponentially decayingI′required by the model is obtained ifI′is identified with a simple logarithmic function of the temperature field.