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.