The River Thames is undergoing a remarkable biological recovery, transitioning from a waterway once declared “biologically dead” to a thriving habitat for diverse wildlife. According to a comprehensive health check conducted by the Zoological Society of London (ZSL), the river is now home to a surprising array of species, including seals, seahorses, and even sharks.

As reported by ZSL, the “State of the Thames” report highlights the significant progress made since 1957, when parts of the river were so polluted they could not sustain life. Today, the Tidal Thames supports 115 species of fish and 92 species of bird. The recovery is credited to improved sewage treatment and the restoration of natural habitats like saltmarshes, which have allowed ecosystems to regenerate.

Photo by enrico bet on Unsplash

The success of the river’s restoration is evidenced by the presence of apex predators. Conservationists have recorded three types of sharks—tope, starry smooth-hound, and spurdog—using the estuary as a nursery ground. Additionally, the report stated that there is an “important population” of harbour seals and grey seals now using the river.

Alison Debney, ZSL’s conservation programme lead for wetland restoration, noted that the river provides “vital services” to London, including protection from climate change. She stated that “this report has enabled us to really look at how far the Thames has come on its journey to recovery,” while warning that the waterway still faces modern pressures.

Despite the positive trends, the report identifies ongoing challenges.