Seals are being deafened by underwater noise in busy shipping lanes, new research suggests.

Scientists studying seals in the Moray Firth compared their experiences to those of people living in noisy inner cities.

They inspected 28 seals and found predicted noise levels were high enough to cause temporary hearing loss in 20 of them.

Ecologist Dr Esther Jones, from the University of St Andrews, 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."

Her team drew up maps showing the extent to which grey and harbour seals around the UK were affected by shipping traffic.

The maps showed that 11 of 25 Special Areas of Conservation may contain seals affected by shipping.

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.

"We now need to begin assessing any behavioural changes of seals as a result of chronic exposure to underwater noise, so that we can understand the implications of those changes on individuals and ultimately on population dynamics."

The scientists now intended to tag seals with sound and movement recording devices to investigate how their behaviour is affected by noise.