Estimating the polar distribution of snapping shrimp with a wide aperture array

Abstract

A wide-aperture array consisting of three widely separated collinear hydrophones is used to estimate the polar distribution of underwater acoustic transients produced by snapping shrimp. Simultaneous differential time-of-arrival measurements from adjacent pairs of hydrophones are used to estimate the instantaneous range and bearing of the source of each biological transient signal. Plotting the source positions for a series of acoustic transient events produces a spatial distribution of the local snapping shrimp population. When DSTO's Wide Aperture Array was deployed in Sydney Harbour, the spatial distribution of the biological transients coincided with the position of a naval wharf suggesting that the sub-surface structure of the wharf is conducive to snapping shrimp habitation.