Researchers carry out annual seal census in the Thames

Researchers have been counting the number of harbour and grey seals basking on the banks of the Thames for an annual census.

The study, which includes analysing hundreds of photographs taken from a plane flying above the river and estuary, has taken place every year since 2013 to build a picture of the harbour and grey seals that call the Thames home.

The team from the Zoological Society of London (ZSL) carry out the count, which monitors the population of adult seals as well as the number of pups born during the breeding season, during August.

This is when harbour seals moult and so spend longer resting out of the water, the experts said.

ZSL conservation biologist Anna Cucknell said: “In the 1950s the River Thames was declared biologically dead and that is still how most people think of it.

“In truth, thanks to decades of dedicated conservation, the Thames is now a thriving habitat and a place where lots of animals come to raise their young.

“Seals are at the top of the Thames’ food chain and rely on healthy populations of lots of other species to survive.

“The fact that the seals are here – and in such numbers – is a sign of how far we have come.”

The latest data on how seals are faring in the Thames will be released in September, and will include the first ever published estimate of how many seal pups are born each year in the Thames.