Marine biologists believe seahorses could be breeding in the UK’s River Thames as the water becomes cleaner.

About five short-snouted seahorses (Hippocampus hippocampus) have been spotted during routine conservation surveys over the last year or so, leading scientists to think they have probably established a resident population.

The news has been kept secret until now because the seahorse has not been protected by law. But beginning on Monday, the marine creature and its environment will have protection under the Wildlife and Countryside Act 1981.

The seahorse has been spotted near Dagenham, Tilbury and Southend. It is thought to be mainly a salt water creature, usually found in shallow muddy waters, estuaries or seagrass beds, so it is not clear how far up the Thames it will go.


But the Zoological Society of London, which released its findings, said the discoveries suggested that the Thames was becoming cleaner.

“It demonstrates that the Thames is becoming a sustainable, bio-diverse habitat for aquatic life,” said Alison Shaw, manager of the Society’s marine and freshwater conservation programme.

“It is not clear how endangered short-snouted seahorses are because there is little data known, particularly in the UK, so every scrap of information is valuable,” she said.

There are signs that the seahorse is breeding on the south coast, too.

Other creatures protected by the Act from Monday include the water vole, angel shark, Roman snail and long-snouted seahorse.