A survey of the River Ching has found evidence of 1,885 different species living in and around the river, including the critically endangered European eel and the Peach Blossom jellyfish.
The 10km river runs from Epping Forest through Highams Park and Chingford before joining the River Lea.
In March 2026, volunteers from the Ching Action Group took water samples at six places along the river. They sent them to Trace Biomonitoring for environmental DNA (eDNA) testing, which picks up traces of DNA that living things leave in the water.
What they found
The results showed:
- 1,885 unique species in total
- 12 fish species
- 4 native amphibian species
- 22 bird species
- 16 mammal species
European eel was detected more often further downstream. There were also some surprises: DNA from Atlantic cod and tuna turned up in the samples, which may point to wastewater or food waste getting into the river. This needs further investigation.
Signs of pressure downstream
The survey found cleaner freshwater habitats in the upper stretches of the river, and more signs of organic enrichment and wastewater pollution further down. Falmouth Avenue Weir appears to be blocking fish, including eels, from moving along the river and reaching habitat.
Sam Bentley-Toon, of the river charity Thames21, said the findings "reveal a diverse freshwater ecosystem", while also showing the pressures urban rivers are under.
The Ching Action Group plans to use the data to support restoration work that tackles pollution sources and barriers to fish migration.
