Continued research and development of signal processing software PAMScan for New Zealand
wThe arrival of affordable state-of-the-art underwater autonomous recorders to market has exploded in recent years. Underwater acoustics is now being used as a tool in a variety of marine fields. That means recording data from multiple sites simultaneously for extended periods of time is now possible, and being done all over the world. It also means big data - really big data. For example, one of our monitoring projects pulls in well over 22 TB a year and with several projects underway at the same time, programming computers to do multiple things at once is vital.
To get around this, we have developed a suite of modules in-house that together form the Matlab-based PAMScan software package that allows the processing of large acoustic datasets for a variety of purposes. Since every project is unique in it's objectives and deliverables, we have been able to further develop and improve PAMScan's capabilities. Custom-designed detectors for vessels, marine mammals and fish, ambient soundscape analyses, noise measurements, eco-indices computations, noise budget calculations, sound source localisation and audio editing can all be undertaken in PAMScan. We are currently working on a Python-based version. |
Studying shallow water noise propagation and marine mammal monitoring for pre- and post-consenting purposes
Studying the propagation loss of signals in shallow waters through modelling and empirical measurements during the pre- and post-consenting phase of coastal developments has become a key part of my daily work life in New Zealand. Using passive acoustics to monitor the presence of marine mammals around busy harbours and coastal developments, as well as seismic surveys, is also a key part of my New Zealand-based research. Working with researchers around the country has lead to the development of state-of-the-art monitoring techniques and efficient data handling and software developments that have been tailored for each individual project (and client).
One example of this is the long-term marine mammal monitoring in Christchurch for the Lyttelton Port Company using SoundTrap autonomous recorders (Ocean Instruments NZ) and CPOD (Chelonia Ltd, UK) devices, with Styles Group Limited (Auckland). Eight monitoring stations with CPODs and/or SoundTraps installed are installed and record continuously the presence of hector dolphins. This monitoring is part of a long term research project investigating the potential effects of dredging (from a trail-suction hopper dredger (TSHD)) on the habitat use of Hector dolphins in Lyttelton Harbour. Another example is the passive acoustic monitoring of whales and dolphins in the Cook Strait using SoundTrap autonomous recorders, as well as ground-truthing propagation models of airgun pulses during seismic surveys off Taranaki. |
Auditory masking from vessel noise for sensitive marine life in the Hauraki Gulf
The greatest impacts from anthropogenic underwater sound pollution are likely to occur in coastal areas with highly productive waters that are close to major port cities. Auckland City in New Zealand is such an example, as it is a port city at the base of the Hauraki Gulf, a large embayment (1.2 M Ha) that is characterised by highly productive coastal waters.
The biodiversity of the Hauraki Gulf Marine Park in northern New Zealand is regarded as outstanding and consequently has been protected through its own legislation, the Hauraki Gulf Marine Park Act 2000. This research project was done in close collaboration with Assoc. Professors Craig Radford and Andrew Jeffs of the University of Auckland. Together, we investigated the detectability of vessel noise in marine mammals, fish and crustaceans The project looked particularly at recreational vessels that do not have automatic identification systems (AIS) and so not as easy to understand their movements within the Hauraki Gulf Marine Park as commercial shipping. The findings show that the sound emanating from both recreational and commercial vessels within the Hauraki Gulf will be significantly raising background sound levels and is likely to have a wide ranging masking impact on marine life. See - Pine, M.K., Jeffs, A.G., Wang, D., Radford, C.A. (2016). The potential for vessel noise to mask biologically important sounds within ecologically significant embayments. Ocean & Coastal Management 127: 67-73. |
In shallow waters, deploying and servicing hydrophones is easier with SCUBA.
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Effects of underwater tidal turbines and offshore wind turbines on larval crustaceans
Underwater tidal turbine technology has advanced at a rapid rate due to increasing commercial interest across many countries. Marine renewable energy in New Zealand is behind other countries, however resource consent applications for the installation of tidal turbine devices in New Zealand have occurred.
This study followed a resource consent application which sought to install NZ's first tidal turbine farm in the Kaipara Harbour. It involved experimenting with crab megalopae (swimming crab larvae) in a laboratory setting, exposing them to different sound treatments. The results provided evidence that noise from the tidal turbine device may delay metamorphosis. Delays in metamorphosis could be concerning as it may lead to unknown ecological impacts on reef systems.
See - Pine, M.K., Jeffs, A.G, Radford, C.A. (2012). Turbine sound may influence the metamorphosis behaviour of estuarine crab megalopae. PLoS ONE 7(12): e51790.
This study followed a resource consent application which sought to install NZ's first tidal turbine farm in the Kaipara Harbour. It involved experimenting with crab megalopae (swimming crab larvae) in a laboratory setting, exposing them to different sound treatments. The results provided evidence that noise from the tidal turbine device may delay metamorphosis. Delays in metamorphosis could be concerning as it may lead to unknown ecological impacts on reef systems.
See - Pine, M.K., Jeffs, A.G, Radford, C.A. (2012). Turbine sound may influence the metamorphosis behaviour of estuarine crab megalopae. PLoS ONE 7(12): e51790.