Seal Count Finds Over 700 In Thames Estuary

There are more than 700 seals living in the Thames Estuary, according to the first count of its kind by conservationists.

Teams of volunteers carried out the count by air, land and water and recorded 708 grey and harbour seals along the Thames for the Zoological Society of London (ZSL) survey.

The figure has surprised scientists who said it was an "incredible" number.

The animals spotted from boats, from the air or by teams on the ground investigating small creeks and rivers, were recorded alongside the GPS co-ordinates of sightings.

The aerial survey enabled researchers to count seals on the outer sandbanks of the estuary where colonies of up to 120 seals were recorded in remote and undisturbed spots away from people and boats.

The county was carried out by land, water and air

It is the first such complete assessment of the seals in the Thames following a boat survey by ZSL last year.

The survey was timed to coincide with the annual seal moult, when harbour seals shuffle on to sandbanks to shed their coats and grow a new layer in time for the winter, making them easier to spot.

ZSL's conservation scientist Joanna Barker said: "We knew there were a lot of seals in the Thames but 708 is pretty incredible.

"In previous results there's been a good few hundred in the Thames, but it's great to have a figure we can use as a baseline."

Scientists will repeat the count in a few years to check whether numbers are declining or increasing.

"Now we know the numbers and where they are, it can help with conservation," Ms Barker added.

A rescued seal pup

The presence of so many seals is good news for the Thames Estuary, which was declared biologically dead in the 1950s as a result of heavy pollution.

Ms Barker said: "It's a really good indicator because the seals are the top predators in the marine food chain, and it shows that the marine environment is relatively good and is producing enough food for the seals to eat."

However, she warned there had been drastic declines in numbers of harbour seals recently across Scotland, and that seal populations elsewhere could be vulnerable.

The reasons for the declines are unclear but could be down to disease, climate change, the shifting of prey species and competition with grey seals.

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