YOU ROLL OFF THE BOAT somewhere in the Indo-Pacific and dip your head below the surface to get a hint of the wonders that await you on the dive. But what’s this? Where is the reef? Where’s the beautiful coral? All you can see is a grey, featureless seabed.
Here and there are scattered piles of debris, washed off the beach by recent rains. You must be in the wrong place.
Fortunately you trust your guides, and an hour and a half later you ascend with your mind reeling and your camera’s memory-card full of pictures of some unimaginable marine life.
Welcome to muck-diving, a highly addictive type of underwater excursion that’s part treasure hunt and part a game of hide and seek, with some very clever opponents.

THE GENESIS
While the first few generations of recreational scuba-divers were marvelling at the beauty of coral reefs and hanging out in the blue watching for whale sharks and mantas, a whole universe of amazing creatures were going about their business under the sea unnoticed.
How could they have remained undetected for so long? Well, first they were small. Second, they had developed the art of concealment to a very high degree. And third, they lived in places that were not particularly pleasing to the eye.
Primarily, however, they stayed unseen because nobody was looking for them.
Then a few things happened to bring these little creatures into the limelight. First, the big fish became fewer in number and harder to find. Second, divers became older and a little lazier. Third, there were significant advances in underwater macro-photography.
Most importantly, a few enterprising individuals in Papua New Guinea, Indonesia and Malaysia started looking for marine life in unusual places where nobody had looked before, and began to find some astonishing animals.
The era of muck-diving had begun.

WHERE TO GO
The best muck-diving seems to be found in places where there is a shallow bay, a river mouth, human habitation, significant current movement outside the bay, shelter (in the form of a pier or jetty) and natural and human debris, such as rotting tree-trunks and tin-cans.
So far, the location that offers the best combination of these ingredients is Lembeh Straits on the north-eastern tip of Sulawesi in Indonesia. Other locations discovered to date that also deserve honourable mention include the whole of north Bali, Indonesia; Dumaguete in the Philippines; Pulau Mabul off the coast of Malaysian Borneo; Ambon and Alor in the eastern Indonesian archipelago and Milne Bay in Papua New Guinea. New places are being discovered all the time.

HOW TO MUCK-DIVE
Move slowly and carefully, staying as near to the seabed as possible without disturbing it. The bottom is likely to be silty, and a misplaced fin can ruin visibility and send rare marine-life flying. Look closely at everything and be patient. This is hard work!
However, what can at first seem an impossible task becomes far easier with experience, and the time you put in to learn your craft rewards you in wonderful ways. The thrill when you find something rare and exotic is hard to beat.

TECHNIQUES
Be aware of the movement of your arms and legs, especially when you’re excited, as this is the time when your appendages are most likely to move of their own accord, without purpose or conscious direction.
As soon as the initial adrenaline has subsided a little, make it a habit to carry out a little review of where you are and what your limbs are doing before settling down to study or photograph your latest find.
Develop a fin-kick that doesn’t shift the water powerfully downwards, such as:
1 A modified flutter-kick, where you move only your feet and fins, pivoting from the ankles and with knees bent so that your fins are above you. You won’t make fast progress with this technique but it ensures that the water you displace when you flutter your fins remains within the water column rather than being directed downwards.
2 A modified frog-kick, where you move your legs apart slowly then bring your fins together more quickly to provide forward propulsion. Again this should be done with the knees bent, so that the fin movement takes place above your body rather than behind it, and the water displaced is directed horizontally behind you.
3 A reverse modified frog-kick, as above but beginning with legs together, then moving them apart simultaneously in a single movement so that the result is reverse rather than forward movement. This is an excellent technique to deploy if you need to remove yourself from a tight corner without using your hands or turning your body.

SHOW CONSIDERATION
These are fragile animals and touching them can damage them. Removing them from their carefully chosen camouflage can also draw them to the attention of the very predators from which they are hiding and, once you have taken your picture and departed in a puff of sand, you may leave them very vulnerable.
Resist the temptation to pick up any trash you find and take it ashore for green disposal. Your heart might be in the right place, but the trash is likely already to have been recycled in the best possible way, and may now be the home of a creature that needs all the protection it can get. So place a temporary curb on your environmental instincts.

EQUIPMENT
Get a “critter stick”! This is a simple 30cm pointer made out of stainless steel that you can either thrust into the sand for balance as you float looking for animals, or deploy to gently guide a piece of intruding weed out of the frame of the photograph you’re taking, without disturbing your subject.
Most muck-diving takes place in shallow water near the shore, and you will spend your time close to the seabed. Keep all your hoses and BC fittings tucked in tight, so they don’t hang down and scrape along the bottom while you’re horizontal.
Make sure that you have a cutting tool accessible – surgical shears are ideal – because much muck-diving is under or close to jetties and there is likely to be fishing-line around. With your attention focused on looking for the cool stuff, you might inadvertently become entangled.
Always take a light with you. An animal that is almost invisible can be much more obvious when you restore its true colours with your beam.
Think about getting a pair of short-bladed fins so you can manoeuvre more easily without disturbing the seabed.

WHAT TO LOOK FOR
You are looking for what muck-divers commonly call “critters.” This is an Americanism and derives from the word creature.
The stars of the muck-diving firmament are rare fish with evocative and poetic names such as rhinopias, fingered dragonet, pegasus sea moth, flying gurnard and clown frogfish; fascinating invertebrates such as blue ring and mimic octopus and flamboyant cuttlefish, and tiny and brightly coloured shrimps, slugs and crabs of all types.
There is no substitute for a sharp eye, but you can increase your chances of success by understanding the behaviour of the animals you’re seeking so that you have an idea of where to look and what to look for. Here are a few tips and tricks that the spotters use:
1 Look ahead as well as beneath you so that you see the octopus or eel that’s poking its head out of a hole before it sees you and beats a retreat.
2 Watch for peripheral movement as you pass. Something may have been spooked into burying itself. Move on, turn and wait. It will re-emerge in time.
3 Examine everything closely. Two
pieces of weed that are bobbing and weaving simultaneously but out of synchronisation with the waves might be Ambon scorpionfish. What looks like a detached piece of sponge next to a rock could be a baby hairy frogfish.
4 Ornate ghost pipefish are often found concealed in the fronds of featherstars. Look for a frond that is not attached to the star. That will be the pipefish.
5 Robust ghost pipefish, on the other hand, hide among seagrass. Look for the leaves moving in the current and try to find a “leaf” that is not moving in rhythm with the others.
6 Search for camouflaged predators such as leaf scorpionfish and frogfish around rocky outcrops with small caves where schools of small fry hide. You will spot moray eels and lionfish in such places, but don’t be satisfied with them.
7 Look for the less obvious motionless predators too. They will be there, though it may take a while to find them. Be as patient as they are.
8 Cans, bottles, coconuts, juice cartons, pieces of bamboo and discarded clam shells are just a few of the things that the veined octopi (Octopus marginatus) may choose to adopt as their residence.

EXAMINE EVERY ONE
Look closely at common creatures that you might normally ignore. For instance, sea cucumbers can host colourful emperor shrimps that live commensally with them.
Swimming crabs also live in folds they make in the sea cucumber’s flesh. Seastars sometimes have harlequin shrimps feeding on them, while sea urchins are often home to shrimps and baby fish that seek shelter between the spines.
Zebra crabs live on fire urchins, small harlequin swimming crabs live on the trunks of tube anemones and porcelain crabs live between the fronds of sea-pens.
Many of the creatures being discovered by muck-divers are new to science and, even where the animals were previously known, new behaviour is being observed all the time. Even now, we’re just scratching the surface.
It’s exciting to imagine what surprises remain to be discovered by someone with patience, a sharp eye and a pointer.

Read more from Simon Pridmore in:
Scuba Confidential – An Insider’s Guide to Becoming a Better Diver
Scuba Professional – Insights into Sport Diver Training & Operations
Scuba Fundamental – Start Diving the Right Way

All are available on Amazon in a variety of formats.