LOCH CRERAN, situated in the north-west of Scotland, is home to a special animal – the serpulid worm. It grows here in abundance, the profusion of white cylinders forming reefs that in turn play host to many different forms of marine life.
The serpulid reefs at Loch Creran are currently the best-known examples to be found in Europe. Less-extensive reefs have been found on the west coast of Ireland and in a lagoon in Italy and, more recently, Loch Teacuis, further west in Morvern, but none can compare with those found in Creran.
The best examples of the reefs are ideally reached by boat in the outer basin. They are usually to be found at 6-10m around the edges of the loch.
Here the worms form the tubes, usually 5-7cm long, in which they live.
These tubes settle one on the other, intertwining until they grow into delicate reefs, which can be up to 75cm high and a metre long.
Several of these smaller structures may even join together, making reefs several metres wide. The reefs tend to form mainly in areas in which there is a suitable hard surface, such as rock and shell on a mud or sandy bottom.
Serpulid worms are filter-feeders that rely on the currents bringing nutrients. As they feed, their feathery scarlet tentacles emerge and the reef is covered with a dazzling display of colour.
They are very sensitive, however, and any disturbance in the water will make them disappear rapidly. Then a scarlet plug is all that can be seen, sealing the end of the tube.
While some of the larger serpulid structures are accessible only by boat in the outer basin of the loch, the inner basin offers opportunities to see smaller examples when shore-diving.
Running along the edge of the inner basin is a road, along which are frequent lay-bys.
Park at the third lay-by on the south side of the loch and you’ll find a set of steps leading down to the shingle beach.
Diving near high tide will mean a slightly safer entry, as the weed-covered rocks can be very slippery.
Swim out and down a gentle slope, then, at around 3m, turn right. Fin over dozens of dog whelks steadily making their way over the sandy seabed among a scattering of brightly coloured seastars, one of which reminds me of a peach melba with its vivid pink and orange colours.
Soon you will begin to find large patches of rocky reefs that slope back up the sides of the loch. Dotted all over these rocks are serpulid worms existing as individuals, their white cylindrical homes stuck fast to the rocks while their delicate scarlet tentacles emerge to feed.
The inner basin also has some large horse-mussel beds. Groups of these can be found scattered all over the loch, their mouths gaping open to feed on the nutrients bought in by the tide.
Loch Creran contains diverse marine life, as can be seen on some of the other dives possible from the shore.
You can do a drift-dive along Creagan Narrows, passing under the bridge before exiting, but local knowledge of tides and suitable entry and exit points are essential.
The currents are strong here, and there is a real danger of being swept into deeper water and away from the shore.
Even when diving in the inner basin, it’s prudent to keep away from the bridge and head up the loch, where it is more sheltered and not affected by tides.
Another popular entry point with locals is the small shingle beach next to the car park at Creagan’s Inn.
This makes for an interesting shore dive in the outer basin, but the ebb tide can be a little swift taking you away from the shore, so I have always dived this on an incoming tide or, better still, at slack.
Swim straight out to around 7-8m and then turn right and follow the rocky reef as it meanders in and out along the seabed.
In this way you can take in the gravelly seabed, alive with dozens of crabs scuttling around, and dragonets sitting motionless, hoping not to be spotted, but also rocky walls covered with translucent sea squirts, spiny squat lobsters hiding from the camera’s big eye, and edible crabs peering from under beetling brows.
This small rocky wall seems to go on indefinitely, and drops to more than 20m. I have dived it on several occasions, but always had to turn back before reaching the end. Mind you, I do have a tendency to dawdle and watch the marine life!
Those who like diving for their tea will find plenty of scallops at a site on the other side of the loch near Rubha Teithil.
Head north from Oban on the A828, which runs along the side of the loch and past the Sea Life Centre. Shortly after passing a picnic area called Sutherlands Grove, and just before the next bend, you will find a small tarmac slip on the loch side of the road and a parking place.
Enter the water here and you will certainly find plenty of scallops living on the muddy bottom.
For others there is an interesting rocky slope to the right in very shallow water, (around 5m at high tide), which means that you can spend a lot of time looking at all the creatures hiding out among the rocks. Several types of squat lobsters are here, along with tiny gobies, sea squirts, dragonets and quite a few serpulid worms dotted around.
Whether or not you are particularly interested in serpulid worms, this beautiful loch with its diverse marine life makes a good place to dive, and if you’re lucky enough, you may even glimpse the dark bullet shape of a seal as it zooms by, checking you out.
Because of the presence of the worms, Loch Creran has become a Marine Special Area of Conservation.
These zones provide good examples of natural habitats and species of wildlife that are rare, endangered or vulnerable in the European community.
It is to be hoped that more places such as this will be identified and protected in the future.

Information about Loch Creran can be found at www.argyllmarinesac.org.uk. Divers often combine a visit to the loch with sea diving from Oban, where airfills are available. Oban Tourist Information Centre, www.oban.org.uk, 01631 563122 can provide guidance on accommodation.