Bring a bottle of Martini Bianco. A big one, one and a half liter if you can. That was how the adventure started. Rubes, the Spanish Diver, was messaging me. We’d dived Richelieu Rock and the Similans in the Andaman Sea together and now he was in Mabul, off Malaysia’s Sabah province in Borneo. And I was going to Chiang Mai airport to fly out.

I barely had enough baht for a liter bottle, but kept a good hold of it through a six-hour layover in Kuala Lumpur’s crappy regional airport, and a connecting flight to Semporna in Sabah (with another stamp in the passport, interestingly, since Sabah and Sarawak provinces in Borneo retained entry controls as part of their 1963 accession agreement). I arrived in Tawau, the nearby port town, pretty frazzled. Next day I was on a boat to Mabul.

Off Tawau the sea bed is a large underwater plain, flat as a mirror, rarely more than two meters below the glassy surface. Everyone gets around in shallow-hulled steel or fiberglass skiffs. Channels for larger vessels were well marked.

And that’s the point. It’s why divers flock to the islands off Tawau. The undersea plateau stretches out for kilometers, until all of a sudden it stops dead. The drop-off into the blue depths at Sipadan is more than half a kilometer, and where the sea is deep, the fish are big.

Still, Sipadan, one of the world’s most famous dive sites, was to be only one day. Day trips to Sipadan that include the permit cost upwards of $250. Only 120 divers a day are given permits, to ensure this precious marine ecosystem stays functional. The rest of the time I’d be muck diving. Muck diving, or ‘looking in the muck for small sea critters,’ was a slight misnomer as the visibility off Mabul itself was exceptional, at up to 40m.

Rubi, an authority on nudibranchs who has a vast collection of photos of hundreds of different species, was training Franco, Nadja, and Alba to be dive masters, and I tagged along. Coco was there too as Arung’s second divemaster. We had our own boat (normally there are 12 divers in one vessel, we had three or four) and set off for the sites around the island. To be awestruck once again, as I always am, at the sheer unconscionable diversity of evolution, preserved under the water as it has not been on land, and disappearing fast as humanity finds ever more ingenious ways to suck ‘value’ out of the ocean.

How about this for diversity:

A four-strong school of shrimpfish, aka razorfish (Aeoliscus strigatus), who swim around perfectly vertically and dart downwards to catch unwary prey. Their unusual posture is an adaptation: they have evolved to hide in upright sea urchin spines. They move as if attached to a rod. The diverse ocean is teeming with evolutionary oddities like these, and much, much weirder, too. PIC: Francesco Gallardo. Right now I’ll say how grateful I am to The General and to Rubi for their beautiful shots, this one being one of The General’s.

The welcome at Arung Hayat on the tiny island of Mabul was of typical Iberian warmth, in part because of my cargo. A birthday would be celebrated, and Rubi had saved some jamon de Jabugo and Idiazabal cheese for the occasion. There are no specialist cheese shops on Mabul, needless to say, and the very thought of these great treats (impossible to find in Asia except in the poshest delis in Hong Kong) had the Spanish Diving contingent in a shaman-like frenzy of anticipation.

Bare wood, plastic chairs and lashings of Iberian good humor: Rubi and Coco chilling on the deck at Arung Hayat. Rubi has moved on; he’s now CEO of BuceoMalapascua and PADI course director at Sea Explorers Philippines. PIC: JC.

Our accommodation was by far the worst on the island, too, but it was dirt cheap compared to Scuba Junkies so no complaints there. Rubi was operating the place on behalf of a Malay owner from the mainland, and so it was ours, and thus a palace of fun. In between dives, we wandered off to the pristine beaches or played chess, drank beer and at night repaired to the Scuba Junkie bar, where Philippine rum dug up from illegal beach caches is sold under the table to punters. It still has a coating of damp sand, as a mark of authenticity.

The incredibly small painted frogfish. Just a couple of centimeters long, Antennarius pictus has a lure between its eyes (hence the family Antennariidae) which it uses to attract unwary prey. Frogfishes never swim, they only walk. One ‘foot’ is visible in this shot. When one sees ‘walking’ fish it’s not so hard to imagine how sea creatures colonized the continents. They simply walked up onto the land! PIC: Rubi Branch.

But OMG: under the water was a world. Drifting along the Lobster Wall, Franco spotted a blue-ringed octopus (its minuscule size, barely 3cm long, made this no mean feat. Franco has such good eyes…). He also managed to find the rare and breathtakingly beautiful mandarin fish, one of a pair that had set up home in a palm tree root ball washed off the island and now on the sea bed. Diving with this group was a constant signed chatter: ‘Look over there! Lion fish!’ ‘Come and check out this frog fish!’ ‘There’s a wasp fish down over there!’ ‘Fimbriated moray!’ ‘Blue spotted sting ray!’ ‘Ornate ghost pipefish!’ Names to conjure with.

The author observing two nudibranchs of the species Chromodoris dianae making love. With eyesight as bad as mine, getting a proper look at macro means using a magnifying glass. And of course, I was dubbed ‘Sherlock’ by the Spanish Divers. Finding a glass suited to undersea adventures was no easy task. This cheap one has now been replaced with a better one made by Bausch & Lomb. PIC: Francisco Gallardo.

The metallic ‘ting’ of pointers drumming on gas tanks (a good way for divers to attract each other’s attention, since the sound carries well under water) was almost constant as my companions’ expert eyes spotted species after species.

Heading out to Kapalai to dive Eel Garden, with Nadja and the author. Rubi prepares tanks in the background. PIC: Francisco Gallardo.

And yes, the nudibranchs were fantastical. Rubi had moved to Mabul partly for this reason; it’s a known hot spot for ‘macro,’ or ‘small stuff’ in everyday parlance.

Chromodoris bullocki. This family of nudibranchs are one of the most colorful. The nudibranch is so called because of its ‘branchs,’ the yellow gills sticking up from its back, are ‘nudi,’ i.e., ‘naked,’ or outside its body. Normally, this mechanism for extracting oxygen from the seawater is inside a creature’s body, as it is with fishes’ gills. Marine gastropod mollusks of this kind eat sponges, soft corals and anemones; their astounding coloration results from the concentrations of indigestible chemical colorants in their food. There are 2,300 known species. Their ethereal beauty and stunning colors add plenty of awe and wonder to the prosaic-sounding ‘muck diving.’ Having lost their shells at the larval stage, nudibranchs either mimic surrounding soft corals (their favorite snack in any case), or deploy aposematism, the use of warning colors. They are extremely poisonous due to the mineral concentrations that arise from their constant coral grazing. Some nudibranchs even ‘borrow’ the stinging cells (nematocysts) of their prey. These cells pass through the nudibranch’s alimentary tract without harming it and are ‘sent’ to various places on the creature’s body to act as a bit of extra protection from harm. New species are discovered regularly. The nudibranch embodies one of the most perfect expressions in nature of evolution’s mind-boggling diversity. PIC: JC

Back on land, Rubi’s 38^th birthday got under way. Apart from the Scuba Junkies bar there was nothing to do on Mabul, and so we entertained each other, royally. We made guacamole, drank the Cinzano with the jamon and repaired to the beach to scoff the cheese with crackers, washed down with rum.

The Divemasters: from left, Nadja, Franco, Coco and Alba. This quartet, and Rubi, made up the ‘Five Eyes’ of our trips. I would float along while they spotted and pointed out all the good stuff. To them I owe many of the wonders I saw off Mabul. PIC: JC.

Little Minx has a T-shirt emblazoned with the legend ‘Dive now, work later.’ But in today’s world of gig economics, the chance to survey such incredible marine wildlife comes rarely. I grabbed the bottle of Cinzano, and grabbed the chance to dive Mabul. I was doubly lucky to be in the company of Rubi and The Divemasters on this incredible trip.

Jamon and Cinzano. Rubi eyes the impending feast with devilish glee. PIC: JC.