The public is being asked to be careful around seals during the breeding season and to leave seal pups alone.

Research by the Swansea University has found that seals are being scared into the water by drones flying to close to them.

This is especially a problem during August to November – the seals breeding period.

Paul Renfro from the Pembrokeshire Coastal Forum has called for drone pilots to be responsible around seals.

Speaking to the BBC, Mr Renfro said: “Plan ahead, know where the sensitive areas are and keep your distance.

"If the seals are starting to notice you, then you're too close.

"Their eyes almost bulge and you can see the stress in their face. When they are starting to look at you then that's close enough."

The National Park Authority (NPA) has published guidance for drone users to highlight the disturbance they can cause to wildlife such as seals and seabirds.

An NPA spokesman said: “The Authority has published “Drones represent just one-way people can disturb seals and getting too close while on the ground or on the water will cause the same problems as flying a device overhead.

“If you encounter a seal pup, keep well away and make sure dogs are kept on a short lead and are under control.

“While some people might think a seal pup left alone on a beach is in difficulty, usually its mother is nearby in the water and will return to the pup when she needs to.

“Seal pups are poor swimmers and need to spend their time resting and growing and should never be chased into the sea.

“The Park Authority runs a series of seal walks during the pupping season each year, which include advice on how you can watch these amazing animals safely and without disturbing them.”

Anouska Mendzil-Griffiths, one of the Swansea University researchers who took part in the study, said the effect of drones was immediately clear, with seals rushing into the water.

Full results from the study will be published later this year.

Click here to download NPA drone guidance or to find out more about seal walk events