Of some 2,723 public sightings, seals were the most commonly spotted, with many of them seeming to enjoy basking around Canary Wharf. However, sightings were also reported as far upstream as Hampton Court Palace.
There were also 444 porpoises and dolphins sighted in the bends of the capital’s famously murky river, with large pods spotted near to Kew Gardens and Deptford in the south-east.
A bottlenose whale even visited the central London waterways in 2006, although it didn’t survive. However, in the past 10 years other whales have also been seen around Gravesend, Kent. The vast range of sightings are especially surprising given that, just 50 years ago, the Thames was deemed “biologically extinct”: too polluted and filthy for marine life to survive. While whales and porpoises were once common in Thames water, it was generally assumed by 1965 that those times were over for good.
But now it seems the tides have very firmly turned. Joanna Barker, European conservation projects manager at ZSL, commented: “Many people looking into the Thames see a murky, dirty environment. But, actually, beneath the waves, it is full of life. We have a huge range of fish and invertebrates, and also top predators.”
Furthermore, seal surveys carried out since 2012 have revealed that there are around 670 harbour seals living in the estuary — which provides a sheltered habitat for the animals — with further numbers of grey seals also thriving.
ZSL has asked the public to send in their photos of marine mammals, in an effort to help further research into life beneath the waves.