Little Penguins’ sensitivity to marine noise pollution

Curtin University researchers in Perth, Australia have used state-of-the-art imaging technology to shed light on the hearing sensitivity of Australian Little Penguins Eudyptula minor and the danger of marine noise pollution. The study is the first to describe how Little Penguins or fairy penguins hear sound both underwater and in air. Study lead Dr Chong Wei (Curtin University) explained Little Penguins are particularly vulnerable to human-made noise as their habitats often overlap with shipping lanes, recreational activities and coastal developments. This is particularly concerning as marine noise pollution is steadily increasing and Little penguin populations are significantly declining.

The researchers created 3D digital models using microCT scans of the heads of three Little Penguins (that had died naturally) to mimic the sounds they can perceive at various frequencies. The experiments revealed Little Penguins can hear sounds across a broad range between 200 and 6,000 Hz underwater, similar to other diving birds like the Great Cormorant. The typical range of vessel and pile driving noise is 20–10,000 Hz.

The research findings are valuable for marine conservation efforts. In order to identify potentially dangerous noise frequencies and to inform management measures aimed at lessening the impact of such noise pollution, it is helpful to understand the Little Penguins’ hearing range. Long-term exposure to loud noises from passing ships and nearby construction may make Little Penguins more stressed and disrupt their feeding habits.

Wei, C. and Erbe, C. (2024). Sound reception and hearing capabilities in the Little Penguin (Eudyptula minor): first predicted in-air and underwater audiograms. Royal Society Open Science 11240593 https://doi.org/10.1098/rsos.240593

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