Venomous sharks discovered in River Thames

Sharks have been discovered lurking in the murky waters of the Thames with the river bursting with life 64 years after being declared “biologically dead”.

Tope sharks - which can grow to 6ft long, the starry smooth houndshark and the venomous spurdog sharks were all found in the first ever State of the Thames Report by the Zoological Society of London (ZSL).

Seahorses, eels and seals were also found thriving in the Thames after vital conservation work improved the river’s health since it was declared “biologically dead” in 1957.

It is believed the sharks use the estuary to give birth and nurse their young thanks to improving water quality and oxygen concentrations in the 215-mile river that flows through London.

Researchers found the aggressive Tope shark in the Thames. The breed is hunted around the world for their fins.

The endangered spurdog shark gets its name from the spines in front of its dorsal fin, which it can use to defend itself by curling in a bow and striking at a predator.

This venom can cause extreme discomfort and swelling in humans. It is one of very few venomous fish found in UK waters along with the stingray and weever fish.

Alison Debney, of the Zoological Society of London, said the Thames now supports more than 115 species of fish, 92 species of bird and has almost 600 hectares of saltmarsh - a crucial wildlife habitat.

She said: “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.

“[In 1957] there were long stretches of the Thames that had such low oxygen concentrations due to all the pollution that entered it, that much of the river was devoid of life.

“There were certainly no fish living within those parts. A few hardy eels were found.”

But since the early 1990’s, the number of fish species found in the Tidal areas of the river decreased, with the cause unknown.

The report also found that climate change has increased the temperature of the capital’s waterway by 0.2C per year on average with water levels increasing every year since records began in 1911.

Sea level at Silvertown has been rising 4.26mm per year on average since 1990.

The Environment Agency has identified industrial and sewage effluent as the main source of nitrate in London waterbodies. In addition, there are many chemicals of concern that are not being regularly monitored, with potentially harmful impacts on the wildlife of the Thames.

Liz Wood-Griffiths, Head of Consents 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, 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”.