Busy shipping lanes could cause 'seal hearing loss'

Seals may experience hearing loss from underwater vessel noise, researchers at the University of St Andrews have said.

BBC news says: The study compares seals inhabiting the UK's busy shipping lanes to humans living in noisy cities.

Lead author Esther Jones said noise could affect how sea mammals such as whales, dolphins and seals find food and communicate with each other.

Eleven out of 25 conservation areas linked with seals were at high risk of overlap with shipping, the study found.

The paper has been published by the Journal of Applied Ecology.

Ecologist Dr Jones, a research fellow at the university, said: "Like humans living in busy, noisy cities, some seals live in areas where there is a lot of shipping traffic and associated noise.
"The UK has some of the busiest shipping lanes in the world, and underwater noise has been increasing over the last 30 years."

The St Andrews team developed maps showing the levels of risk of exposure to vessel traffic for grey and harbour seals around the UK.

"This is particularly pertinent to harbour seals that are declining in some regions around the UK, as half of SACs [Special Areas of Conservation] associated with them had a high risk of exposure to shipping," Dr Jones said.

"Exposure risk was highest within 50km [31 miles] of the coast and any impacts will have the greatest effect on harbour seals as they generally stay close to land."

The team investigated the underwater noise levels generated by vessels that individual animals were exposed to in the Moray Firth using predictive acoustic noise models.
For 20 out of the 28 animals observed in the study, the levels of predicted noise were high enough that temporary hearing loss could occur.

The university said there was no evidence that seals were exposed to noise levels high enough to cause permanent hearing damage.

Dr Jones added: "Urbanisation of the marine environment is inevitably going to continue, so chronic ocean noise should be incorporated explicitly into marine spatial planning and management plans for existing marine protected areas."