This spiny seahorse seems to have developed some sort of relationship with a short-snouted seahorse
British seahorses have won official protection, but is this worth a light? asks Steve Trewhella, who often hangs out with these rare creatures in Dorset
AS A BRITISH DIVER AND UNDERWATER PHOTOGRAPHER, I get tired of being told: 'You should have been in the Red Sea last week!' I don't understand why UK divers are so enthusiastic about marine life in foreign seas when we have such amazing creatures right here on our doorstep. I am always keen to get in the water, especially in Dorset, where I live. There's a lot to be said for spending an hour and a half in shallow water, not having to check your computer and air gauge every five minutes. I generally don't need to move far from the drop-in spot, because the more closely I look, the more I see. On my wish-list of native marine life to photograph, seahorses have always been near the top. After 25 years of searching, imagine my excitement on seeing my first, a pregnant male, in 2004, not 15 minutes' drive from home. The site, at Studland, near Poole Harbour in Dorset, is a very busy recreational beach with an estimated million visitors each year. It belongs to the National Trust. On summer days more than 300 boats may be anchored in the bay, with their tenders moving to and from the beach. The seagrass meadows in the sunlit shallows extend out into the bay, and create an extraordinarily rich habitat for a multitude of species. Predatory cuttlefish and shoals of bass patrol above the metre-high blades, while 15-spined sticklebacks, gobies, wrasse, pipefish and all kinds of juvenile fish seek shelter down below. Spiny spider crabs, masked crabs, swimming crabs, brown shrimps and many other crustaceans bury themselves in the sand or forage in the shade of the swaying grass stems, while sea-snails, snakelocks anemones and hydroids live in the light-drenched 'canopy'. The seagrass meadows at this uniquely important marine site are home to all six species of British pipefish, including the rarely recorded Nilsson's pipefish. And this is currently the only known site in Britain with breeding populations of both types of native seahorse - the spiny or long-snouted and the short-snouted varieties. More recently, I have been diving to obtain photographic evidence of damage inflicted on the seagrass beds by boat anchors and mooring chains. In April 2008, seahorses and their habitat were added to a list of British wildlife given legal protection under the Wildlife & Countryside Act 1981, and I wished to see the only proven breeding site for native seahorses given adequate protection from boat damage. In exactly the same spot as my first seahorse-sighting four years earlier was another pregnant male spiny seahorse. Surely this would help the case for protecting the site? Over the following two weeks, I dived the site with various interested parties and representatives of conservation organisations. I collected evidence of damage and saw seahorses on every dive - almost 30, including pregnant short-snouted seahorses.
NO MATTER HOW OFTEN you see seahorses, the awe of their presence never diminishes. It is almost like a mythical creature, a fish that looks like nothing if not a horse; relying to such an extent on its camouflage that it remains fixed to the spot, prehensile tail wrapped as tightly around its blade of seagrass as a baby's finger curls around its mother's. As it sways gently with the swell, blending with its surroundings, it gracefully turns its head away and down to the seabed to hide its tell-tale eye from a potential predator, trying not to give away the fact that it is a fish, rather than a piece of drifting alga. A unique finding among a series of extraordinary discoveries was a pair of seahorses with their tails entwined, as if a courting couple - but the male was a pregnant short-snouted seahorse, while the female was a spiny. Were they a breeding pair, or had they unintentionally grasped each others' tails as they moved about among the weed? These sightings, I felt, highlighted that this remarkable site needed protection from potential damage and to be managed to provide a sustainable future for both the seahorses and their rich and diverse habitat. I was sure that this could be achieved, with seahorses and their habitat now protected by law. However, in reality the site faces a very uncertain future, and protection from anchor damage of even a small part of the seagrass meadow appears unattainable. When seahorses and their habitat were added to a list of other species already protected, no thought was given to how this could be enforced or, indeed, to what they were being protected from. The offence is 'intentional or reckless damage', and because sea creatures are out of sight, out of mind, any harmful activity is automatically seen as accidental. So even if you are aware of the problems of dropping an anchor, if you damage seagrass beds, or even injure or kill a seahorse, deliberate intent to do so must be proven. Initial excitement at discovering this exceptional site, and belief that it could be protected, has turned to despondency and resignation. What we see today is for our eyes only, and future generations of divers will blame us that it was allowed to decline and disappear. Still, they can always go to the Red Sea.
Guidance for divers Do not touch, disturb or follow a seahorse. Observe it in situ, and allow it to accept your presence before photographing it. If it moves away, do not chase it. Taking a seahorse is illegal. Report any sightings to the British Seahorse Survey run by the Seahorse Trust, www.britishseahorsesurvey.org Because it is so busy, Studland can be a dangerous place to dive. Divers should avoid weekends and school holidays, and always use an SMB - though bear in mind that many boat-users don't realise what these signify!
British seahorses The two British species are the spiny seahorse, Hippocampus guttulatus, and the short-snouted seahorse, Hippocampus hippocampus. The former prefers to live in seagrass, while the latter is found in a wide range of seabed habitats, including seagrass. In spring and summer, seahorses move into shallower water to breed. Females produce eggs and deposit them in the male's breeding pouch, where they develop. After approximately 28 days, around 300 baby seahorses are born. The male can become pregnant again almost immediately. Seahorses pair for life, and during the breeding season they undergo an elaborate courtship display each morning. Juvenile seahorses fend for themselves from the moment of birth and are prey to many animals - very few will survive to adulthood. In winter, seahorses move offshore into deeper water to avoid storms and wave action. More information can be found on the Seahorse Trust website, www.theseahorsetrust.co.uk
A diver observes one of the Studland seahorses.
A fine example of a spiny seahorse at Studland Bay.
Unfortunately for them, this is where the seahorses call home.