Estimating density from single hydrophones by means of propagation modeling.

Abstract

A density estimation method developed under the project Density Estimation for Cetaceans from passive Acoustic Fixed sensors is presented. It uses sound propagation modeling to estimate the probability of detecting an animal as a function of its distance from the receiving sensor. Two case studies involving Blainville’s beaked whales (Mesoplodon densirostris) and sperm whales (Physeter macrocephalus) are analyzed. The study area is the Atlantic Undersea Test and Evaluation Center in the Tongue of the Ocean, Bahamas. A ray‐tracing acoustic propagation model is used to estimate the environmental transmission loss as a function of depth and range in several directions away from a single hydrophone. The computed transmission loss is compared to ambient noise levels, source level, and beam pattern distributions available in the literature to estimate detection probability as a function of range. Detection threshold is characterized from the signal‐to‐noise ratio of detected clicks. Information on click product...