The Environment Agency, a UK-based watchdog organization responsible to the British and Welsh governments, has found evidence of a colony of seahorses in the Thames, during a routine fisheries survey at Greenwich. According to a release by the organization, this is the first time that seahorses have been found so far upriver, as well as in this part of London.

Traditionally, seahorses have been commonly spotted in coastal waters around the British Isles. However, these sightings could indicate that there may be more permanent populations in the area.

"The seahorse we found was only 5cm long - a juvenile - suggesting that they may be breeding nearby. This is a really good sign that seahorse populations are not only increasing, but spreading to locations where they haven't been seen before. We routinely survey the Thames at this time of year and this is a really exciting discovery," said Emma Barton, an Environment Agency Fisheries Officer, in a statement.

The Agency has been regularly monitoring the population of marine life within the Thames estuary, from approximately the 1980s. The data they have gathered, Barton indicated, could help understand the importance of the river as a nursery and breeding ground for a number of species important to both commercial and ecological imperatives.

The particular species found - the Short-Snouted Seahorse or Hippocampus Hippocampus - can grow to about 15cm in length and are relatively rare in the UK, appearing usually off the southern coast. Seahorses are one of the few animals in the world that mate for life, following elaborate courtship rituals.

"We hope that further improvements to water quality and habitat in the Thames will encourage more of these rare species to take up residence in the river," Barton added.

Earlier, in 2008, seahorses were protected under the 1981 Wildlife and Countryside Act; prior to this a handful of individuals had been found in the Thames. This raised the possibility that the river may be supporting a colony. Seahorses, unfortunately, were not found since that time and certainly were never found so far inland.