A Miniature Acoustic Device for Tracking Small Marine Animals or Submerged Drifters

Abstract

This paper presents an acoustic archival tag capable of tracking small marine animals. It is also a technology that can be ported to other platforms such as next generation acoustic and Argo floats as well as gliders. Tracking is achieved by standard RAFOS triangulation using the arrival times of unique sound signals emitted by moored sources. At the core of the tag is a custom microchip, which controls all system operations. It incorporates the critical acoustic arrival time detector, a thermal sensor and a pressure sensor interface. All electronic components are housed inside a cylindrical hydrophone of 25.4 mm length and 10.7 mm diameter. The collected data is archived in nonvolatile memory chips with a total capacity of 4 Mb, sufficient storage to record position, temperature and pressure on an hourly basis for two years. The tag consumes 4-5 W in standby mode and between 60-90 W while the sound arrival time detector is in operation. The power is provided by two button cell silver-oxide batteries, which enable an active tag lifetime of approximately two years.

The ocean’s movescape: fisheries management in the bio-logging decade (2018–2028)

“…However, like acoustic tracking, we predict many of the challenges of satellite tracking will be resolved or at least improved within the next decade. Two of the most promising advances are: the use of acoustic signals to geolocate animals under the ocean (Fischer et al, 2017;Rossby et al, 2017), and the development of increased satellite tracking and tag capacity through the ICARUS initiative (Wikelski et al, 2007).…”

“…POSYDON's goal is to develop an undersea positioning system (e.g. the equivalent of an underwater GPS) based on long-range acoustic signals propagated in known locations and detected by surface sensors with satellite connectivity, similar to the technology being used to develop new archival fish tags (Fischer et al, 2017;Rossby et al, 2017). This positioning system would allow AUVs and drones to obtain accurate positions without needing to surface (https:// defensesystems.com/articles/2017/02/14/darpauuv.aspx?…”

An Acoustic Archival Tag for Long-Range Tracking Of Small Fishes

“…If so desired, pressure and temperature can be sampled more frequently than searching for sound signatures. A more detailed description of the chip's features and its design can be found in reference Fischer [8].…”