The joys of muck diving

MUCK DIVING sounds the very antithesis of coral-reef diving. Reef divers swim through a world of colourful coral heads populated by strikingly patterned fish, scuttling arthropods and awesome molluscs. Muck divers explore apparently unpromising sand flats and muddy silts devoid of visible inhabitants. Muck divers, though, see reef divers as the lightweights of the scuba world—people in search of the obvious. Muck diving is about searching for the unusual, the cryptic and the rare.

Though enthusiasts discovered muck’s attractions less than ten years ago, and the species that live in it were similarly ignored by science, muck diving is now big business. Tallies are not kept, but research conducted in 2014 by Maarten De Brauwer, a marine biologist at Leeds University, in Britain, who is an expert on muck diving, suggests that 100,000 tourists visited the Philippines and Indonesia that year specifically to dive on the muck. This brought $150m into the region. In the Philippines the fishing villages of Anilao in Luzon, and Dauin in Negros Oriental, have been particular beneficiaries of the growth of this sort of tourism.

Dr De Brauwer thinks of divers who explore these sediments as the marine equivalent of bird watchers, ticking off species in a sort of zoological competition. Top of the list is that master of disguise, the...