SHERMAN, M.L.*; MOORE, P.A.: Boundary-layer Effect on the Chemical Signal Movement along the Body of the Brown Bullhead

Flow speed influences the spatial and temporal distribution of a chemical signal. However, a boundary layer exists around the olfactory appendages and can further influence the distribution of chemical signal. The goal of this research is to quantify how morphology and fluid flow interact to influence the movement of a chemical signal along an organism’s body. This research is critical for understanding the interaction between hydrodynamics and sensory biology. Brown bullheads have taste buds along their body that are used to sense chemicals that mediate a variety of behaviors. The chemical signal was measured using the IVEC 10 along the body of a model brown bullhead. Several parameters, including peak length, peak rise time, maximum height, absolute slope, and maximum slope were analyzed as well as a spectral analysis. Differences in signal parameters were found along the body and at different flows. These results show that the presence of the model, flow and position on the fish model affects the chemical signal properties and thus influences the type of information the bullhead can perceive. There is an interaction occurring between flow, the presence of model and specific areas on the fish. This indicates that the morphology of the body affects signals attributes and acts as a sensory filter.