Marine Mammal Hearing Test Reveals Potential Impact of Anthropogenic Noise

A team from Curtin University and Taronga Conservation Society Australia has conducted the first hearing tests on Australian sea lions and long-nosed fur seals, revealing which sounds they can hear and establishing a baseline for assessing the impact of anthropogenic noise. The study took place at Taronga Zoo in Sydney, where two Australian sea lions and two long-nosed fur seals were trained to press a pedal when they heard a specific tone, receiving fish as a reward for correct responses. Both species were most sensitive to sounds around 3.2 kHz, marking the first established hearing sensitivity baseline for these two Australian species. The research was published in the journals 'Conservation' and 'Animals'. Professor Elbe from Curtin University stated, "Before we can understand if noise affects animals, we first need to know if they can hear it." When these seals rest on land, they can actually hear a wide range of human-generated sounds quite clearly – including boat engines, airplane roars, train rumblings, and even construction noise along the coast! This is particularly important for the endangered Australian sea lion, with a population of only about 12,000 individuals, which relies on hearing for communication, foraging, navigation, and detecting threats. Behavioural ecologist at Taronga Conservation Society, Picheler, noted, "We've established what they can hear in air; the next step is to understand the impact of underwater noise and when it starts to interfere with behaviour or hearing." The research can provide a basis for environmental impact assessments and noise management, aiding in the development of more precise conservation strategies as shipping, coastal development, and offshore industries expand. It must be incredibly stressful to constantly hear all sorts of human-generated noise when they come ashore...