title: A large-aperture low-cost hydrophone array for tracking whales from small boats.
abstract: A passive sonar array designed for tracking diving sperm whales in three dimensions from a single small vessel is presented, and the advantages and limitations of operating this array from a 6 m boat are described. The system consists of four free floating buoys, each with a hydrophone, built-in recorder, and global positioning system receiver (GPS), and one vertical stereo hydrophone array deployed from the boat. Array recordings are post-processed onshore to obtain diving profiles of vocalizing sperm whales. Recordings are synchronized using a GPS timing pulse recorded onto each track. Sensitivity analysis based on hyperbolic localization methods is used to obtain probability distributions for the whale's three-dimensional location for vocalizations received by at least four hydrophones. These localizations are compared to those obtained via isodiachronic sequential bound estimation. Results from deployment of the system around a sperm whale in the Kaikoura Canyon in New Zealand are shown.
authors.affiliation: Department of Marine Science, University of Otago, Dunedin 9054, New Zealand.
authors.forename: B
authors.initials: B
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Dawson
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D025041:Animal Migration; D000818:Animals; D004242:Diving; D004867:Equipment Design; D040362:Geographic Information Systems; D009520:New Zealand; D012767:Ships; D013017:Sound Localization; D050661:Sperm Whale; D014828:Vocalization, Animal