Seahorses thriving in cleaner river Thames, scientists say

Jessica Aldred, The Guardian 7 Apr 08;

The discovery of a colony of short-snouted seahorses (Hippocampus hippocampus) living in the Thames means that the London river is becoming cleaner, conservationists said today.

Scientists from the Zoological Society of London (ZSL) have discovered five seahorses during routine conservation surveys in the Thames estuary in the past 18 months, evidence which they say indicates that a breeding population exists.

The rare species, which is normally found in the Mediterranean and Canary Islands and also along the south coast of England, has been found at Dagenham in east London and Tilbury and Southend in Essex. The sea creatures thrive in shallow, muddy waters, estuaries or seagrass beds.

Scientists at the ZSL say the presence of the seahorses in the Thames estuary is a good sign that river quality is improving, but warned that any disturbance to their habitats could be disastrous.

The presence of a breeding population has been kept quiet to date as the species was not protected, the zoo said. But last month, the short-snouted and spiny seahorses, along with the water vole, angel shark and Roman snail, became the latest species to gain legal protection under the Wildlife and Countryside Act.

The laws, which came into force today, mean that anyone found killing, injuring or taking any of these species from the wild faces a £5,000 fine or six months' imprisonment.

They join species such as the otter and grass snake that are already protected under the 1981 act and, in addition, the possession of or sale of the water vole, short-snouted seahorse, spiny seahorse and Roman snail will become and offence. It will become an offence to damage or obstruct the seahorses' places of shelter or disturb them in their place of shelter.

Alison Shaw, the manager of London Zoo's marine and freshwater conservation programme, said: "These amazing creatures have been found in the Thames on a number of occasions in the last 18 months during our wildlife monitoring work.

"It demonstrates that the Thames is becoming a sustainable biodiverse habitat for aquatic life. Now they are protected, conservationists are more relaxed about telling the world they are there."

Seahorses are threatened by overexploitation for traditional medicines, aquariums and curiosities, accidental capture by fishing fleets, and degradation of their habitats.

Many seahorses are included on the International Union for Conservation of Nature (IUCN) red list of threatened species as vulnerable or data deficient, as not enough is known about the species. The Knysna seahorse, (Hippocampus capensis), from South Africa, is recognised as endangered.

Both long and short-snouted seahorses are housed at London zoo's aquarium, which manages the European breeding programme for both species. Scientists are studying their life history and behaviour in an effort to understand more about them so they and their habitats can be better protected.

ZSL is also the co-founder and partner in the global Project Seahorse initiative, which focuses on the conservation and sustainable use of the world's coastal marine ecosystems. The project is conducting two studies – one to determine how seahorse populations differ across Europe and a second researching how seahorses are affected by environmental change.