Donate

The Thames Estuary is home to harbour seals, grey seals, harbour porpoises and sometimes even dolphins and whales! ZSL has been collecting public sightings of these marine mammals since 2004 and they are frequently sighted all the way up to Richmond.

These sightings form a crucial part of our understanding of the biodiversity in the Thames and help us conserve these charismatic top predators.

If you are lucky enough to see a marine mammal, please follow our code of conduct and report your sighting.

View the map and report a sighting

seal swimming in London
seals london in river

Marine mammal code of conduct

The Greater Thames Estuary is home to harbour porpoises, harbour seals, grey seals and sometimes whales and dolphins too! If you spot a marine mammal, please follow this code:

If you see a marine mammal while on land...

  • Stay 50m away
  • Put your dog on a lead and walk away
  • Never touch a seal. You or it could get hurt.
  • Do not presume a seal pup is 'abandoned'. Its mother may be feeding nearby.

If you see a dead or stranded marine mammal, please call 0800 6520333.

If you see a marine mammal while on the water...

  • Stay 100m away
  • Do not chase, swim with, or feed the animal
  • Only watch for 15 minutes
  • Travel at a slow, 'no wake' speed
  • Ensure the animal is not confined between vessels or between vessels and the shore
  • Ensure no more  than two vessels are around the animal at one time

Report a sighting

Thank you for assisting us with our Thames marine mammal conservation work.

seals code of conduct infographic

View the map and report a sighting