At Sydney’s Taronga Zoo, keepers trained two sea lions and two fur seals to listen for a tone and push a paddle when they heard it. Each correct response earned the animal a piece of fish.

Curtin University professor Christine Erbe explained that these tests give researchers a baseline of what the animals can hear, which is needed before judging whether ship, boat, aircraft or construction noise might affect them.

The peer‑reviewed study showed the four pinnipeds were most sensitive to sounds near 3.2 kilohertz.

Erbe also noted that the endangered Australian sea lion, with an estimated 12,000 individuals, depends on hearing for communication, hunting, navigation and spotting danger.

Behavioural biologist Benjamin Pitcher said the results could be used in environmental impact assessments and guide noise‑management policies as shipping, coastal development and offshore industries continue to grow.

Understanding the hearing range of seals and sea lions is a first step toward protecting them from harmful noise.