Poisonous sharks found in London’s Thames River

A study by the Zoological Society of London (ZSL) revealed “positive news” for wildlife and ecosystem restoration, the community said Wednesday.

Spurdogs, like the one in this file image, have poison-secreting spines on their dorsal fins.

Spurdogs, like the one in this file image, have poison-secreting spines on their dorsal fins.

Pally / Alamy Stock Photo

Back in 1957, the capital’s river was declared “biological dead”.

But now, surprising creatures such as sharks, including tops, starlings, smooth dogs and spur dogs – a slender fish measuring about 23 inches and covered in poisonous spines – have been found.

Spurdogs can be found in deep water, and the spine in front of the shark’s two dorsal fins secretes a venom that can cause pain and swelling in humans.

Top sharks, like the one pictured here in a file image, can reach six feet in length.

Top sharks, like the one pictured here in a file image, can reach six feet in length.

gaze / Alamy Stock Photo

Tope sharks, which feed on fish and crustaceans and can reach 6 feet and up to 106 pounds, have never launched an unprovoked attack on humans, according to Britain’s Wildlife Trusts.

Meanwhile, the star-clear smooth dog, which can reach up to 4 feet and 25 pounds, eats mostly crustaceans, shellfish and mollusks.

However, the number of fish species found in the river’s tidal areas has shown a slight decrease, and nature conservation researchers have warned that further research is needed to understand why.

File image of a starry smooth dog.  These sharks mostly eat shellfish and crustaceans.

File image of a starry smooth dog. These sharks mostly eat shellfish and crustaceans.

Pally / Alamy Stock Photo

The 215-mile-long river, home to more than 115 fish and 92 bird species, faces pollution and threats to climate change, ZSL warned.

The river also provides drinking water, food, livelihoods and protection from coastal floods to surrounding communities.

Climate change has increased the Thames’ temperature by 0.2⁰C a year on average, ZSL said, warning that this “paints a worrying picture” when combined with sea level rise.

The water level has risen since monitoring began in 1911 in the tidal section of the Thames, and has risen at some points by 0.17 inches per year on average since 1990.

“As water temperatures and sea levels continue to rise above historical baselines, estuary wildlife will be particularly affected through changes in the species’ life cycle and range,” ZSL warned in a statement.

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