Hearing in marine fauna

Understanding how animals detect and respond to sound is a growing area of research with major implications for environmental impact assessment and conservation management. Our research focuses on the auditory systems, sound reception mechanisms, and hearing impairment of marine fauna including dolphins, pinnipeds (seals and sea lions), fish, seabirds, and invertebrates.

At CMST, we use a multidisciplinary approach combining physics, engineering, and biology to study auditory function across multiple species. Our team has pioneered imaging-based numerical modelling to predict hearing sensitivity in animals where traditional testing is challenging or unfeasible. We also conduct behavioural experiments and collaborate widely across academia, government, and industry to address complex bioacoustic questions.

This research provides the scientific foundation needed to assess the risks of anthropogenic noise, such as shipping, pile driving, offshore wind farms, and seismic surveys, and supports evidence-based policies for marine spatial planning and species conservation.

CT/MRI scan and data analysis

CT/MRI imaging is a non-invasive technique, and can provide very detailed information on animal structures without causing any damage to the specimen and can be used for constructing accurate numerical models.

We collect fresh stranded specimens for high-resolution CT/MRI scanning. For the large-sized whales, only the ear parts are scanned, for the middle-sized dolphins and whales, only the heads of the specimens are scanned, and for the small-sized animals, such as fishes, the whole body is scanned.

We extract geometry information of the specimens and export the Hounsfield Unit (HU) values of tissues for three-dimensional (3D) model construction. Figure 1 shows an example of a CT scan of a bottlenose dolphin.

Figure 1: Inner ear anatomy of the Australian sea lion. 3d reconstruction.

Figure 2: 3D reconstruction of an Australian sea lion ear structure

Recent Projects

• WAMSI Westport Projects

Using CT/microCT imaging and finite-element modelling techniques, these projects predicted the first audiograms for endangered Australian sea lions and little penguins both in air and under water. They also investigated sound reception mechanisms in Australian snapper.

• Department of Climate Change, Energy, the Environment and Water (DCCEEW)

This project examines hearing sensitivity in Australian pinnipeds and assesses their vulnerability to offshore wind farm noise.

• Australian Acoustical Society (AAS)

Using CT-based modelling, this project investigated sound reception mechanisms and the impact of noise on Australian sea lions.

• Perth Zoo Collaboration

This project conducted behavioural response experiments to determine the hearing sensitivity of little penguins both on land and under water.