Despite increasing concern about the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species, such as the Little Penguin (Eudyptula minor). In this study, we collected freshly deceased Little Penguins for dissection and microCT scans. The head structures, including the ear apparatus, were reconstructed based on high-resolution imaging data for the species. Moreover, 3D finite-element models were built based on microCT data to simulate the sound reception processes and ear responses to the incident planar waves at the selected frequencies. The received sound pressure fields and motion (i.e., displacement and velocity) of the internal ear-related structures were modelled. The synergistic response of ear components to incident aerial and underwater sounds was computed to predict the hearing capabilities of the Little Penguins across a broad frequency range (100 Hz–10 kHz), both in air and under water. Our predicted data showed good agreement with other diving birds in both the form and range of auditory sensitivity. This study demonstrates a promising method to study hearing in other inaccessible animals. The outputs from this study can inform noise impact mitigation and conservation management.

A working group from the Global Library of Underwater Biological Sounds effort collaborated with the World Register of Marine Species (WoRMS) to create a global inventory of species categorized by known underwater sonifery. The inventory is provided as an ecological trait on WoRMS (MarineSpecies.org), where it may be regularly updated. The purpose of this Borealis dataset is to store spreadsheet versions of any updates to the data on WoRMS. The methods used to create the dataset are described in a peer-reviewed article (Looby et al. 2023. Scientific Data. 10:892. https://doi.org/10.1038/s41597-023-02745-4). The original dataset is available in figshare (https://doi.org/10.6084/m9.figshare.c.6704481.v1) to serve as a permanent record of what was peer-reviewed and will therefore not be updated.

To date, there has been no dedicated study in Australian waters on the acoustics of killer whales. Hence no information has been published on the sounds produced by killer whales from this region. Here we present the first acoustical analysis of recordings collected off the Western Australian coast. Underwater sounds produced by Australian killer whales were recorded during the months of February and March 2014 and 2015 in the Bremer Canyon in Western Australia. Vocalisations recorded included echolocation clicks, burst-pulse sounds and whistles. A total of 28 hours and 29 minutes were recorded and analysed, with 2376 killer whale calls (whistles and burst-pulse sounds) detected. Recordings of poor quality or signal-to-noise ratio were excluded from analysis, resulting in 142 whistles and burst-pulse vocalisations suitable for analysis and categorisation. These were grouped based on their spectrographic features into nine Bremer Canyon (BC) “call types”. The frequency of the fundamental contours of all call types ranged from 600 Hz to 29 kHz. Calls ranged from 0.05 to 11.3 seconds in duration. Biosonar clicks were also recorded, but not studied further. Surface behaviours noted during acoustic recordings were categorised as either travelling or social behaviour. A detailed description of the acoustic characteristics is necessary for species acoustic identification and for the development of passive acoustic tools for population monitoring, including assessments of population status, habitat usage, migration patterns, behaviour and acoustic ecology. This study provides the first quantitative assessment and report on the acoustic features of killer whales vocalisations in Australian waters, and presents an opportunity to further investigate this little-known population.