The soundscape ecology of the fin whale (Balaenoptera physalus) in Antarctic and Australian waters
Supervisors: Robert McCauley, Christine Erbe, Ben Saunders and Brian Miller
The fin whale is a globally vulnerable species which faces a wide range of threats to recovery. Two sub-species are currently recognised: one in the Northern Hemisphere and one in the Southern Hemisphere. Literature pertaining to the Northern Hemisphere sub-species offers a rounded description of the soundscape ecology of the fin whale with long-term analysis of their acoustic repertoire, seasonal distribution between high and low-latitude regions and the ambient noise environment of fin whale habitats. In contrast however, there is a lack of broad-scale, long-term understanding of the Southern Hemisphere sub-species of fin whale and their acoustic ecology.
The overall aim of this research project is to fill in the gaps of this knowledge within Antarctic and Australian waters by a) developing tools for the study of fin whale acoustic ecology, b) characterising the acoustic repertoire of fin whales, c) identifying the temporal occupancy and spatial-distribution of the animals, and, d) investigating if the animals make alterations to their vocal displays in response to ambient noise. In order to analyse long-term acoustic recordings of fin whale calls, data will be obtained from the Australian Integrated Marine Observing System (IMOS), the Comprehensive Test Ban Treaty Organisation (CTBTO) nuclear test monitoring station and the Australian Antarctic Division (AAD).
Positive identification and classification of fin whale calls can be used to infer animal presence, habitat use and population parameters. Furthermore, potential threats to the species can be explored through assessment of ambient noise in regions of fin whale presence. This knowledge may inform conservation management of fin whales at an international and national level.
Acoustic ecology of commercial fish species on Australia’s southern continental shelf
Supervisors: Robert McCauley, Christine Erbe, Ben Saunders and Iain Parnum
The earth’s oceans are being exposed to human and natural disturbances. It is crucial to enhance scientific understanding of marine ecosystems in order to measure and manage the impacts of these disturbances. Passive acoustic monitoring is a cost-effective and efficient method of collecting ecological data. The acoustic monitoring of soniferous fish species delivers explicit, non-invasive and long-term data on their behaviour and distribution. Knowledge of the acoustic behaviour of fish is still relatively limited and it is imperative that this is addressed for fish to be used as indicators for ecological change.
This PhD project will study the ecology of fish choruses commonly recorded along the edge of the southern Australian continental shelf from Portland, Victoria, to Bremer Bay, Western Australia. I aim to determine the spatiotemporal patterns and environmental drivers of these choruses via analysis of existing and newly collected passive acoustic, oceanographic and remote sensing data. Field surveys, to be conducted off Bremer Bay, Western Australia, Port Lincoln, South Australia and possibly Portland, Victoria will procure new passive acoustic data and underwater video footage to be used for identification of the fish species producing the choruses. Fish samples of the chorus species will be collected and dissected to examine the structure of the auditory systems of the fish.
This study will expand scientific knowledge of soniferous fish species and how they interact acoustically with the marine environment and each other. This project will contribute to the development of a successful method for ground-truthing fish choruses occurring along the edge of continental shelves and will obtain explicit ecological data which may be used to inform ecosystem and species management. This research has the potential to inform sustainable management of commercially harvested fish species and may contribute to the development of an autonomous, cost-effective and non-invasive monitoring tool for fish populations.
Source depth estimation from acoustic intensity vector sensors
Supervisors: Dr Alec Duncan, Dr David Matthews
Investigation of in-field devices for underwater surveying of reef structures
Supervisors: Iain Parnum, David Belton and Petra Helmholz
There are three commonly used methods for underwater surveying: acoustics (multibeam echo sounder), passive light (photogrammetry), and active light (laser). Each method can be accurate in creating and detecting features on the seafloor. However, each system has its own strengths and limitations. This project will be investigating how accurate and precise each method is at measuring underwater structures, such as artificial reefs. Where possible, the methods will be carried out on a known structure, e.g. where it has been directly (physically) measured or fabricated with known specifications. The study will also carry out repeat measurements in order to quantify accuracy and precision of the methods. The study will conclude by examining the effect of combining data from different methods (i.e. data fusion), to determine the best approach for underwater surveying
Monitoring seafloor habitats using multibeam echo-sounders
Supervisors: Iain Parnum, Michael Kuhn, Sasha Gavrilov and Justy Siwabessy
Anthropogenic activities have influenced all parts of the oceans including most isolated areas. These impacts can be reduced through better ocean management using different approaches which rely on accurate and high-resolution marine seafloor habitat maps. Unfortunately, available benthic habitat maps are seldom at the level of details and scales required for efficient ocean management using those approaches. Moreover, the seafloor is an arbitrary temporally and spatially changing environment due to multiple biological and physical processes. Thus, research and development of robust strategies and methods for mapping and monitoring marine seafloor habitats to tackle these challenging marine environmental issues is necessary and urgently needed.
Multibeam echo-sounders (MBESs) are the most advanced, complex, and effective available acoustic remote sensing systems for marine seafloor habitat mapping especially for deep and turbid water areas. Despite these advancements in multibeam survey technology and the key role of multibeam backscatter data in marine habitat mapping and monitoring, there is no standardized way to acquire, process, classify, and interpret acoustic backscatter data for producing marine habitat maps. To have a long-term management strategy for marine habitats, it is important to understand how well multibeam data can be used to monitor marine habitats. However, it is unclear how repeatable or how much change can be detected with such multibeam derived maps. The overall aim of this study is to develop methods for monitoring habitats with MBES, and to determine the level of marine habitat change that can be detected with multibeam data.
This study can be achieved using the existing data held at Centre for Marine Science and Technology (CMST) and publicly available data from shallow water international conferences and Geoscience Australia (GA). This research will review and evaluate the latest methods for producing consistent mapping for marine habitat discovery as well as marine habitat monitoring. Backscatter data will be processed and used to produce marine habitat maps using signal-based data processing software available at Curtin University such as CARIS Hips and Sips, Fledermaus FMGT, and CMST. Where ground-truth data is available then supervised maps will be produced, where no ground-truth data has been collected unsupervised maps will be produced.
This research will provide the appropriate and practical guidelines and recommendations regarding the system settings choice, the optimal data processing and analysis methods and strategies to obtain the highest benefits of monitoring marine seafloor habitat using multibeam systems. This is significant to current marine habitat mapping technology and marine resource management strategy based on marine habitat maps because there has been less attention to these issues in the literature.