In the murky depths of the River Thames, below Tower Bridge, lies an often unseen world of wildlife and ecological magnificence. However, this has not always been the case.

Pollution in the Thames

From the 1880s until the late 1950s, the so-called Pool of London proudly proclaimed its position as the largest port in the world. It also reclaimed the title of the most polluted, and by the 1950s, the river was declared 'biologically dead'. 

Fortunately that is now a thing of the past. Since the decline of the Port of London over the following decade, passionate conservators, sewerage improvements and industrial governance have seen the ancient waterway flourish once again. 

What wildlife lives in the Thames?

Smelt fish

Fantastic fish

Although it may be hard to spot through the thick silt, mud and sand, the River Thames is home to some 125 different species of fish. Stretching from Teddington Lock in the west out to the Thames Estuary, some of the more well-known varieties include seabass, sole and even trout.

The river is also home to some more obscure fish, such as the zander or the cucumber-smelling smelt. Many of the fish that live in the Thames are migratory, making their way up to London from as far afield as Siberia.

Image: The smelt © Wikimedia Commons

Egyptian goose at Tower Bridge's high-level West Walkway

Brilliant birds

Where there are fish you are sure to find birds. Several different species live in and near the river.

These include Canadian and Egyptian geese, swans, herons and wagtails. A number of oyster beds serve their feeding requirements.

Once a favourite of dock and river workers, wild oyster beds have declined in size rapidly across the UK by as much as 95%, but they can still be found in the Thames Estuary.

A grey seal pup

Mighty mammals

Famously, on 19 January 2006, a northern bottlenose whale swam up the river to Battersea, after losing its way in the North Sea. The six-metre-long female whale can now be seen in the Natural History Museum.  

The Thames is also home to a vast array of other mammals. Seals make up a huge part of the ecology, numbering close to 4000 across the two species of harbour and grey seals. Even though most of these seals live on sandbanks and coastal creeks, some have been sighted following fish as far west as Richmond. 

Image: A grey seal pup © Alastair Rae/Wikimedia Commons

European Eel

Conserving the Thames

With the increased protection of the Thames by organisations like the Port of London Authority, the London Wildlife Trust and the Zoological Society of London, its growing ecosystem continues to flourish.  

The range of animals living in and around the Thames continues to grow in its diversity and appeal, albeit often hidden. These mysterious waters are the ideal habitat for many fascinating creatures, from slippery European eels to the rarely sighted short-snouted seahorse and even Tope and Starry Smooth-hound sharks. 

Image: European eel © Illustration by Italian ichthyologist Felice Supino/Wikimedia Commons