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Environment

29th Dec 2021

Wildlife returns to the Thames 60 years after it was declared biologically dead

Simon Bland

The Thames is currently home to 115 species of fish, 92 species of bird and almost 600 hectares of carbon-eating saltmarsh

The River Thames in London is showing signs of a recovering ecosystem after a recent survey revealed evidence of thriving wildlife – including seahorses, eels, seals and even sharks – despite the river being declared biologically dead in 1957.

As reported in multiple outlets, a new survey conducted by the Zoological Society of London (ZSL) showed promising signs of life in the iconic London river in the society’s inaugural State of the Thames Report.

More than 60 years ago, the Thames was declared “biologically dead” after an inspection showed it was unable to support any wildlife or life forms. However the ZSL’s new findings have given new hope for the river’s future, with dedicated conservation efforts shown to have dramatically transformed the health of the body of water and its ecosystem.

As it stands, the Thames is currently home to a range of bird and marine animals, alongside natural habitats such as saltmarsh which captures carbon from the atmosphere and helps to alleviate symptoms of global warming.

Perhaps one of the most exciting revelations from the report is evidence of a number of shark species present within the river, including breeds like spurdog, tope and starry smooth sharks. This is particularly positive news considering the number of fish species in the Thames has been in decline since the 1990s.

Still, the report did reveal a number of concerning factors, like sewage spill which increases the water’s nitrate levels and ultimately damages its wildlife. Climate change has also had an impact, increasing the water’s temperature by 0.2 degrees a year.

Thankfully, with new works to sewage treatment on the horizon, it’s hoped that these issues can soon be tackled.

“Estuaries are one of our neglected and threatened ecosystems. They provide us with clean water, protection from flooding, and are an important nursery for fish and other wildlife,” Alison Debney, ZSL Conservation Programme lead for wetland ecosystem recovery told UniLad.

“The Thames estuary and its associated ‘blue carbon’ habitats are critically important in our fight to mitigate climate change and build a strong and resilient future for nature and people.

“This report has enabled us to really look at how far the Thames has come on its journey to recovery since it was declared biologically dead, and in some cases, set baselines to build from in the future.”

Meanwhile, Head of Consents at Tideway, Liz Wood-Griffiths, added: “This report comes at a critical time and highlights the urgent need for the Thames Tideway Tunnel, known as London’s new super sewer.

“The new sewer, which is due to be complete in 2025, is designed to capture more than 95 per cent of the sewage spills that enter the River from London’s Victorian sewer system.

“It will have a significant impact on the water quality, making it a much healthier environment for wildlife to survive and flourish.”

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