Short-snouted seahorse.

Marine biologists are reporting a surge in the number of seahorse sightings in the River Thames, highlighting the importance of London’s estuary for wildlife.

Six individual animals have been sighted in the past two months alone, compared with the previous average of one or two sightings a year,  the Zoological Society of London (ZSL) said.

The most recent find, a short-snouted seahorse, was recorded by an ecological survey team working at Greenwich. It is not yet known what has caused the rise in reported sightings.

While research work has so far been limited, the Thames is thought to be home to two seahorse species in particular - the short-snouted seahorse (Hippocampus hippocampus) and the spiny seahorse (Hippocampus guttulatus).

However, Anna Cucknell, ZSL’s conservation manager for estuaries and waterways, said: “There’s currently a real lack of scientific data on the wider status and populations of these two seahorse species in the Thames and throughout their range.”

It is hoped the recent findings will attract funding for further research.

In addition to seahorses, the Thames is known to be home to a number of species, from shrimp and insect larvae, to more than 125 species of fish, including the critically endangered European eel, as well as harbour seals and grey seals. ZSL said the new finds underline how little we know about the many species living in the iconic waterway.

Members of the public can get involved in the research efforts by reporting their own sightings to iSeahorse.org and the Seahorse Trust’s National Seahorse Database. The public can also sign up to ZSL’s Thames conservation team as volunteer citizen scientists.

Image © Anna Cucknell