TACOS - Tassie Acoustic Society

3 August 2017

The TACOS seminar was held on Wednesday, 2 August in the Aurora lecture theatre in the IMAS building in Hobart. We had the privilege of listening to talks from our very own Toby Jarvis and Damien Guihen from the Australian Maritime College, UTAS. A special thank you also goes out to Ben, who helped in organizing this event. We look forward to many more!

Our first presenter, Toby Jarvis, gave a talk entitled “Multibeam echosounder data processing for water-column targets: a case study from the deep sea”. Details on his talk are given below.

Co-author list: Katherine M. Dunlop, Kelly J. Benoit-Bird, Chad M. Waluk, David W. Caress, Hans Thomas, Kenneth L. Smith Jr

Abstract:

Multibeam echosounders (MBES) were first developed in the 1970s for seafloor depth mapping (hydrography) and habitat mapping. Nowadays they are also being used to detect water-column targets such as marine mammals, diving birds, fish, zooplankton, suspended sediment and gas bubbles.

In this talk I shall present a proof-of-concept study from the deep sea, in which we used data from a downward-looking RESON SeaBat 7125 MBES mounted on a Dorado-class autonomous underwater vehicle (AUV) to detect and characterise the location and movement of backscattering targets (which were likely to have been individual fish or squid) within 50 m of the seafloor at ~800 m depth in Monterey Bay, California.

I will provide a brief overview of the experimental setup followed by a detailed look at the data and how we chose to process it.

Our second speaker, Damien Guihen from Australian Maritime College, UTAS, gave a talk entitled: "Autonomy and Acoustics: opportunities and pitfalls of pinging robats". Details on his talk are given below.

Co-author list: Guihen, D., Fielding, S., Brearley, A., King, P., Bowden-Floyd, I., Zurcher, K., Forrest, A., Kemp, N., Haulsee, D., Lee, W.

Abstract:

Underwater robots give us the opportunity to explore in space and time that have not been possible with ships, moorings or floats. We can now send single high-performance vehicles on days-long missions under Antarctic ice or establish roving fleets of slow-moving vehicles to survey for months on end.

Autonomous Underwater Vehicles of all sorts use sound both for navigation and observation, like ships, but must then use a pre-programmed logic to act on these data, sometimes with unexpected consequences. The acoustic data used to avoid obstacles doesn't always make sense in an environment where water can spontaneously freeze, and what's a robot to do?

Acoustic data collected by autonomous vehicles can be novel in their format and can be challenging to interpret. The detection of Antarctic krill using slow moving, diving vehicles opens the door to repeated synoptic surveys of the marine ecosystems but are the data comparable to historical data sets.

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