Small cetacean monitoring from surface and underwater autonomous vehicles

Abstract

We present results of Passive Acoustic surveys conducted from three types of autonomous marine vehicles, two submarine gliders and a surface wave powered vehicle. Submarine vehicles have the advantage of operating at depth, which has the potential to increase detection rate for some species. However, surface vehicles equipped with solar panels have the capacity to carry a greater payload and currently allow for more on board processing which is of particular importance for high frequency odontocete species. Surface vehicles are also more suited to operation in shallow or coastal waters. We describe the hardware and software packages developed for each vehicle type and give examples of the types of data retrieved both through real time telemetry and recovered post deployment. High frequency echolocation clicks and whistles have been successfully detected from all vehicles. Noise levels varied considerably between vehicle types, though all were subject to a degree of mechanical noise from the vehicle itself.