Spurdog, a type of venomous shark, found in the river Thames
The Thames river has come a long way since the days of The Great Stink. In the summer of 1858 the combination of untreated human waste, industrial effluent, and an inadequate sewer system raised a tremendous pong in the London metropolis. In the words of Michael Faraday
Near the bridges the feculence rolled up in clouds so dense that they were visible at the surface, even in water of this kind. ... The smell was very bad, and common to the whole of the water; it was the same as that which now comes up from the gully-holes in the streets; the whole river was for the time a real sewer.
Hundreds of tons of lime were dumped into the river and curtains in the Houses of Parliament were soaked in lime chloride to mitigate the miasma, but to little avail. Finally Parliament authorized a massive infrastructure undertaking. A new sewer system was constructed under the leadership of Chief Engineer of London’s Metropolitan Board of Works, Sir Joseph Bazalgette, and things got better.
But they didn’t stay that way. The new sewer system may have gotten rid of the stink, but population and industrial growth over the next hundred years put a strain on the river to the point where, in the 1950s, it was declared biologically dead. In 1960, another mission to clean up the Thames was undertaken, involving improved sewage treatment, removal of industrial discharges, and the introduction of biodegradable detergents
So that’s why the presence of venomous sharks in the Thames is kind of a big deal. Along with seals, porpoises, salmon and a 125 other species of fish, hundreds of species of invertebrates, waterfowl and shore birds.
But it is not happily ever after. It is never happily ever after in the balance between the biosphere and the anthrosphere, because global warming is now a threat to the health of the river.
Climate change has increased the Thames' temperature by 0.2⁰C a year on average, [Zoological Society of London] said, warning that this "paints a worrying picture" when combined with sea level rises.
Water levels have been increasing since monitoring began in 1911 in the tidal section of the Thames, rising at some points by 0.17 inch a year on average since 1990.
"As water temperature and sea levels continue to rise above historic baselines, the estuary's wildlife will be particularly impacted, through changes to species' lifecycles and ranges," ZSL warned in a statement.
Venomous sharks found in London's Thames river
In the words of pseudo Mad-Eye Moody: Constant vigilance!
