Seahorse Species

Short Snouted Seahorse (Hippocampus hippocampus) and the Long Snouted Seahorse (Hippocampus guttulatus)


There are two species of seahorse in UK waters: the short snouted (above left) and the long snouted (above right, which is also known as the spiny seahorse). They can both grow to a maximum length (or height) of around 15cm and live in shallow, inshore waters amongst seaweeds and seagrass which they cling to with their tails. The main difference between the two species is, unsurprisingly, the snout, although the long snouted seahorse can be further distinguished by the presence of longer spines on the back, just above the dorsal fin. Both species of seahorse can change colour to a limited extent to match their surroundings. Seahorses feed mainly on very small marine crustaceans.

Being mostly a tropical and sub-tropical species neither seahorse species has a wide distribution around the UK. The short snouted sea horse is only found around the English Channel, off the south west coast of England and parts of the southern Irish coast, whereas the long snouted has a wider distribution being found in all of these areas, as well as in parts of Wales and northern Scotland. Seahorses are often taken by predatory fish and have to rely on camouflage to avoid detection as they are poor swimmers, with only their small dorsal fin undulating to provide them with weak forward propulsion. Seahorses have an unusual breeding pattern. Males will fight each other for a mate and once other suitors have been fought off a male and female may breed together for several breeding seasons. The female passes eggs on to the male who then fertilises them within his own body. The eggs grow and hatch within the male who then gives birth to live young when the eggs hatch inside him.

The IUCN (International Union for the Conservation of Nature) does not have enough data on seahorse numbers to make an accurate assessment of their numbers and classes them as Data Deficient. While breeding populations of seahorses have been found in the River Thames around Southend-on-Sea, in other areas where they are present such as Studland Bay in Dorset threats such as drilling for oil threaten their future. This population is still thought to be present and breeding today. For this reason there is much concern over the long term stability of UK seahorse populations. Seahorses in UK waters are protected under the Wildlife and Countryside Act meaning that it is an offence to kill, injure, capture or possess seahorses in British waters. In addition to this seahorses are now protected under CITES (Convention on International Trade in Endangered Species).

Seahorse Sightings and The Seahorse Trust

If you see a seahorse please report it to The Seahorse Trust who run the National Seahorse Database (they would love to hear of seahorses from all around the world, so please send them all in).

You can find a reporting form by clicking here and can could e-mail it with any pictures to Please include contact details in case they need more information.

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