A recent Thames health check in London found that wildlife has returned to the water and the ecosystem is recovering, 60 years after being declared biologically dead.
The search for the Zoological Society of London (ZSL) has found seahorses, eels, seals and sharks in the tidal river, showing positive signs for its future.
ZSL’s very first State of the Thames Report used 17 different indicators to judge the health of the natural environment, finding that dedicated conservation efforts had made a huge difference to the ecosystem.
The report found an increase in a range of bird species, marine mammals and natural habitats, including carbon-capturing salt marshes, as well as’ surprising seahorses, eels, seals and sharks. Which include the tope, the starry greyhound and the dogfish.
The number of fish species in the river has declined since the early 1990s.
Of particular concern is that climate change has increased the temperature of the waterway by 0.2 degrees per year, as well as a rise in sea level.
Alison Debney, ZSL Conservation Program Manager for Wetland Ecosystem Recovery, said: “Estuaries are one of our neglected and threatened ecosystems.
“They provide us with clean water, protection against flooding and are an important nursery for fish and other wildlife.
“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 humans.
“This report has allowed us to really see how far the Thames has come in its path to recovery since it was declared biologically dead and, in some cases, to establish baselines from which to build upon. to come up.”
The dissolved oxygen concentration in the Thames has improved which is a positive sign as low levels of oxygen concentration can kill fish and phosphorus concentrations have decreased which has been associated with an improvement in Wastewater.
The discharge of sewage into water is a long-term concern as it leads to problems such as nitrate concentration, which can impact water quality and harm wildlife.
There are also a number of other chemicals of concern in the water, which will hopefully be improved by future sewage improvements.
Liz Wood-Griffiths, Consents Manager at Tideway, said: “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, due for completion in 2025, is designed to capture more than 95% of the sewage spills entering the river from London’s Victorian sewer system.
“This will have a significant impact on the quality of the water, which will make it a much healthier environment for the survival and development of wildlife.”
The Environment Agency is also forecasting climate-induced changes with its Thames Estuary 2100 plan, which sets out a long-term approach to adapt to rising sea levels.
The Thames is home to more than 115 species of fish, 92 species of birds and has nearly 600 hectares of salt marshes which provide critical habitat for a wide variety of wildlife.