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Blog: Passive acoustic mooring - 15 March

A couple of days ago we deployed the last of three long-term passive acoustic monitoring moorings, as a collaboration between the Ross-RAMP MBIE Endeavour project and The Australian Antarctic Division.

A humpback whale spyhopping out of the water.

Pippa Low, University of Auckland

Humpback whale surfacing
Pippa Low, University of Auckland

This is part of a global effort to learn more about whales in the Southern Ocean via the Southern Ocean Research Partnership, with several countries deploying similar equipment around Antarctica in recent years. The three moorings we have deployed will record whale vocalizations for the next year until the 2019 Tangaroa voyage comes back to pick them up. They are tuned to pick up a wide range of whale song frequencies, but one is specifically aimed at listening for blue whale calls, while the other two are tuned for sperm whales.

The moorings have been deployed at depths from 500-1500 m on the northern flank of the Iselin Bank in the Ross Sea, on Scott C Seamount, and on the Pacific-Antarctic Ridge.

Scientists back on land use the acoustic data to understand which species are in these areas at specific times. The number of calls can also be used to assess how many whales are in an area at one time. Individual whales can be distinguished by their call so these data paint a picture of who is where, at what time of year, and within as well as between species.

 

One of the Passive Acoustic Moorings laid out on deck ready for deployment. The moorings are composed of weights, floats, the acoustic data recording devices and an acoustic release that will allow the mooring and instruments to float to the surface when triggered by the crew on the 2019 Antarctic voyage that will come and pick them up.
David Bowden, NIWA

Malcolm Clark helps to guide the floats into the water during the Passive Acoustic Mooring deployment.
David Bowden, NIWA

The Bosun Glen Walker, Steve George, Sarah Searson, and AB Peter Wall deploying the Passive Acoustic Mooring.

David Bowden, NIWA

Research subject: AntarcticaMarine Mammals