Conservationists take to sea and air to check wellbeing of Thames seals - Zoological Society of London

Almost 600 harbour and 3,000 grey seals now call the Thames Estuary home, reveals our latest seal survey highlighting the importance of the iconic river for these doe-eyed, native species.

We have been monitoring the grey and harbour seal populations in the Greater Thames Estuary since 2013, and this year’s count – completed by teaming up with military helicopter pilots based at RAF Shawbury – revealed how these two important apex species are doing.

Conservation Project Officer Hannah McCormick, who led the survey, said: “During the 2024 seal survey, we counted 431 harbour seals and 714 grey seals laying out on sandbanks along the Thames. By combining these with the number of seals estimated to stay in the water during the counts, we can estimate that there are a total of 599 harbour seals and 2,988 grey seals. These numbers are key to helping us understand how these two species are doing – alongside feeding into our understanding of how seals across the country are faring and giving us a glimpse at the important habitat the estuary provides. A flourishing ecosystem has enough food, shelter and space for all of its inhabitants, and although we still have a way to go in terms of improving the health of this important habitat, as top predators, this seal population show us that there is good habitat available to the species that call the Thames home.

Taking to the air and sea, the team conducted the surveys by both observing the seals from boats along the estuary and joining training flights with RAF Shawbury’s No 1 Flying Training School to cover the Greater Thames Estuary coastline and sandbanks between Suffolk and Kent.