Low frequency scattering from dynamic fish schools based on collective animal behavior modeling

Abstract

Low frequency acoustic scattering from swim bladder fish is dominated by the monopole resonance response of the bladder. A school scattering model has previously been developed [Feuillade et al., J. Acoust. Soc. Am. 99(1), 196–208 (1996)] to predict levels of scattering from schools of bladder fish, which includes multiple scattering effects among the fish, and coherent summation of their radiated fields. In order to incorporate these acoustic interactions, the relative locations of the individual fish within the school are required as an input. To provide a realistic description of fluctuating levels of scattering from schools, a self-organizing model of group formation in three-dimensional space has been developed, based on biological principles of collective animal behavior [Couzin et al., J. Theor. Biol. 218, 1–11 (2002)]. In this model, organization within the school is a function of alignment, and repulsive and attractive tendencies based upon the position and orientation of the individual fish. The results of using this model to simulate the fish behavior demonstrate the spatial and temporal dynamics of the fish school, and indicate how these influence the statistical variability of the acoustic scattering response as a function of frequency. [Work supported by ONR.]