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Over 100 seal pups born in London’s River Thames 60 years after river declared ‘biologically dead’

Source: zsl.org

The first ever comprehensive count of seal pups born in the Thames has provided evidence that harbour seals are breeding in London’s river, with an incredible 138 pups recorded during the pioneering pup-count undertaken by the Zooloical Society of London in 2018.

138 harbour seal pups born in the Thames in a single year

A survey carried out by the Zoological Society of London (ZSL), which runs London Zoo, has found there are  more than 3,500 seals now living in the Thames estuary — 1,104 harbour seals and 2,406 grey seals — and conditions in the revitalised waterway are so good the seals are breeding too. ZSL counted an amazing 138 seal pups in the river in 2018. 

The first ever comprehensive count of seal pups born in the Thames has provided evidence that harbour seals are breeding in London’s river, with an incredible 138 pups recorded during the pioneering pup-count undertaken by the Zooloical Society of London in 2018.
The Thames is home to both harbour seals and grey seals, though it is only the harbour seals that breed there. The first ever comprehensive count of seal pups born in the Thames has provided evidence that harbour seals are breeding in London’s river, with an incredible 138 pups recorded during the pioneering pup-count undertaken by the Zooloical Society of London in 2018. Source: zsl.org

Scientists took photos from a light aircraft as the seals rested on the sandbanks and creeks below

Scientists from the Zoological Society of London (ZSL) tallied up the total of 138 harbour seal pups after analysing hundreds of photos taken during the seal’s summer pupping season. The results of this analysis were released for the first time last week and form part of UK-wide seal monitoring initiatives. 

The team took photos from a light aircraft as the seals rested, undisturbed on the sandbanks and creeks below. It is much easier, and so more accurate, to count the seals in photos instead of the constantly moving, playful creatures. The Thames is home to both harbour seals and grey seals, though it is only the harbour seals that breed here. 

Conservation Biologist, Thea Cox said: “We were thrilled to count 138 pups born in a single season. The seals would not be able to pup here at all without a reliable food source, so this demonstrates that the Thames ecosystem is thriving and shows just how far we have come since the river was declared biologically dead in the 1950’s.” 

Project Manager, Anna Cucknell, who leads ZSL’s Thames conservation explained: “The restored ‘Mother Thames’ – as we call her – is an essential nursery habitat and home to many animals including more than 100 species of fish, including two species of shark, short-snouted seahorses and the Critically Endangered European eel.

“Incredibly, harbour seal pups can swim within hours of birth which means they are well adapted to grow up in tidal estuaries, like the Thames. By the time the tide comes in they can swim away on it. Grey seals, on the other hand, take longer to be comfortable in the water, so breed elsewhere and come to the Thames later to feed.” 

Source: ZSL.org

Harbour seal pups can swim within hours of birth which means they are well adapted to grow up in tidal estuaries, like the Thames. By the time the tide comes in they can swim away on it.
Harbour seal mother and pup in the Thames mudflats. Harbour seal pups can swim within hours of birth which means they are well adapted to grow up in tidal estuaries, like the Thames. By the time the tide comes in they can swim away on it. Source: zsl.org/©GrahamMee

The Zoological Society of London has conducted Thames seal population estimates annually since 2013

The most recent results, from 2017, recorded 1,104 harbour seals and 2,406 grey seals across the estuary.

The population surveys show that seal numbers in the Thames are rising but it is yet unknown if this is due to resident seals having pups or from adults migrating from other regions where colonies are known to be dwindling. 

For the first time in 2018, therefore, the team at ZSL undertook a breeding survey. The aim going forward is that the two survey methods will complement each other and allow researchers to better understand the seals in the Thames and the reasons behind their changing numbers.

And launching also this month in London Bridge as part of Totally Thames Festival, budding explorers are invited to take their own underwater adventure and meet some of the extraordinary animals that call Mother Thames home, including seals. 

ZSL’s Thames virtual reality experience, the first of its kind in the UK, created by BYO, Somewhere Else and using Timescope technology, and supported by the Royal Bank of Canada, gives adventurers the chance to join ZSL on a Thames safari and journey through one of London’s most important wildlife habitats.

Source: ZSL.org

Grey seals take longer to be comfortable in the water, so breed elsewhere and come to the Thames later to feed.
A grey seal Grey seals take longer to be comfortable in the water, so breed elsewhere and come to the Thames later to feed. Source: zsl.org
“One of our survey photos of a seal 'haul out site' from last year's seal breeding survey. We match these photographs with waypoints, double and triple check the count, and we can create a map of seal distributions in the area.”
The team took photos from a light aircraft as the seals rested, undisturbed on the sandbanks and creeks below. “One of our survey photos of a seal ‘haul out site’ from last year’s seal breeding survey. We match these photographs with waypoints, double and triple check the count, and we can create a map of seal distributions in the area.” Source: zsl.org
The Thames Estuary is home to harbour seals, grey seals, harbour porpoises and sometimes even dolphins and whales! ZSL has been collecting public sightings of these marine mammals since 2004 and they are frequently sighted all the way up to Richmond. To see interactive map, click link?
Thames Marine Mammal Map The Thames Estuary is home to harbour seals, grey seals, harbour porpoises and sometimes even dolphins and whales! ZSL has been collecting public sightings of these marine mammals since 2004 and they are frequently sighted all the way up to Richmond. To see interactive map, click link? Source: ZSL.org
ZSL Seal Survey 2019 There are two species of seal in the UK, the harbour seal and the grey seal; over the last 15 years we have seen substantial changes in their numbers. ZSL initiated annual seal population surveys in 2013, when the seal colonies in the Thames were some of the least studied in the country. The latest results have now been released, and so far things are looking very positive for both species, with an upward trend in both. Source: YouTube/ZSL

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The Thames needs all of us to ensure a future for its amazing wildlife. Join our #MotherThames campaign as we celebrate the secret wildlife in our capital city and work together to protect it. Sign up to ZSL’s conservation newsletter.