More than 500 grey seals have been recorded at a Cumbrian nature reserve for the first time following a careful conservation programme.

Using drone technology, Cumbria Wildlife Trust counted 518 seals at the South Walney Nature Reserve in Barrow between September 2020 and March this year.

It is a jump of 7.2% on the results published in March 2019 when 483 seals were logged, and up 43.9% from 2018’s number of 360.

Drone surveys are carried out fortnightly in the reserve from September to March to monitor the population from year to year.

Data is also gathered on their behaviour to assess how the animals – which can reach up to 2.6m in length and weigh up to 300kg – are impacted by human disturbance such as watersports.

Dr Emily Baxter, senior marine conservation officer at Cumbria Wildlife Trust, said: “This is very exciting news and is a five-fold increase in the population of grey seals during the nine years that I’ve been with the trust.”

South Walney Nature Reserve is the only grey seal colony in Cumbria.

The grey seal is the largest of the two seal species found in the UK – the other is the common seal.

The seals spend most of their time out at sea feeding, but “haul out” on to rocks, islands and secluded beaches during the winter months.

Females give birth in the autumn and their fluffy white pups stay on land until they have lost their baby coats and trebled their body weight.

To monitor the South Walney population by drone, conservationists needed special permission from Natural England and have to fly them very high to avoid distressing the seals and other wildlife.

Dr Baxter said volunteers still manually count the seals, which involves them crawling along the shingle beaches watching the animals through binoculars, in order to compare the two data sets.

“Both methods are important, but the drone gives us more accurate numbers,” she said.

Seal beaches are closed to the public in a bid to protect them from disturbance by people and dogs.

But during lockdown there were problems with people landing kayaks on protected areas, causing a disturbance and scaring some of the seals into the water.

“When seals are disturbed, they flee into the sea, using up important energy stores,” Dr Baxter said.

People who wish to see the seals up close are asked to do so via the Cumbria Wildlife Trust’s “seal cam” which is livestreamed on to its website.