The Recording and Interpretation of Pressures in Prey-Sucking Fish

摘要: Possible pitfalls of techniques used to record pressures in prey-sucking fish have been analysed by applying control systems and hydrodynamic theory. Fourier analysis revealed a bandwidth 1 kHz be generally sufficient for an accurate recording the overall pressure waveform. The exact needed depends on species, specimen size intensity feeding act. A greater than may when secondary fluctuations (e.g. due vortices) are also recorded accurately. Large errors (i.e. same order magnitude as real pressure) dimensions transducer itself cannot excluded theoretical grounds. Most reliable records were made with catheter tip transducers, possessing small broad (about 3 kHz). Pressure Amia calva, Salmo gairdneri, Esox lucius, Gadus morhua Perca fluviatilis. largest negative peak was measured (-42 kPa). Accurate simulations using model suction MULLER, et al. (1982) which new boundary conditions added. This takes into account unsteady nature flow. good correlation between simulated suggests, but does not prove, that: 1) is description process feeding; 2) obtained transducers small. inside mouth has velocity acceleration components head expansion forward motion fish. Forward strongly influences profile events two fast-swimming studied, gairdneri lucius. literature measurements reviewed.