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Seraya Secrets - Bali Muck Diving, Pt 1


12 October 2017

Situated a few kilometres east of Tulamben, a gently curving bay and black sand beach marks what was once one of Bali's best-kept secrets. Now firmly on the diving map, 'Seraya Secrets' and the stretch of beach either side now attracts plenty of divers, particularly those armed with a camera, who come to search the rocks, sponges and expanses of black sand for a fantastic array of critters.

The site has no well-defined geographical boundaries.  To the east, just past Scuba Seraya Resort, a small jumble of rocks crosses the beach and there is a small headland and reef known as Batu Niti.  To the west is Noisy Reef, directly in front of Bali Diving Academy's dive base and again marked by a few rocks on the waterline.  In between, the underwater terrain is decidedly unexciting and certainly nothing to look at.  Typical of sites in this area, the surge zone consists of smooth, black rocks and pebbles which give way to a gentle black sand slope that descends into the depths.  From east to west, the slope gradually undulates with sheltered 'valleys' and rounded ridges that catch any currents.  Some of these ridges are quite dramatic - just in front of a new resort, a knife-like ridge of sand descends from the shallows, much like a big dune on dry land.




At Noisy Reef, there is a proper reef with plenty of hard corals, fire corals and bushy hydroids in the shallows.  This gives way to a dense carpet of encrusting life, with sponges, ascidians, hydroids and algae completely covering the bottom in places.  As you head east, this encrusting life gradually disappears until at Seraya Secrets, in front of Scuba Seraya Resort, the sand beyond the pebbles is almost completely clear.  This area is also siltier, probably due to the presence of a river mouth just to the east.  However, beyond 10-15m or so, the bottom is very similar across the entire site.  The ridges have the greatest concentration of life, with small encrusting sponges, hydroids, crinoids and ascidians all feeding on particles of food brought to them in the currents, while the valleys are sand chutes with less life.  White, feathery hydroids start to become more common in the deeper sections and there are a few rocks and big barrel sponges scattered across the whole area.



Typical of a muck site, it is not the scenery that attracts the divers.  Instead they come here to hunt for critters, particularly the diversity of crustaceans and nudibranchs that make this area so special.  Harlequin shrimps are probably Seraya's most famous inhabitants and can be found anywhere on the site, even out on the open sand on occasion.  Pairs or threesomes like to hole-up in rocky crevices and can be found in the same spot for months at a time, making life easy for the guides.  More elusive, but equally beautiful, are Seraya's tiger shrimps.  These spectacular shrimps are much harder to find due to their small size but the guides normally have a good idea where one can be found.  They tend to make their home at the base of a small sponge and like harlequin shrimps, specialise in eating echinoderms - brittlestars for tiger shrimps, starfish for harlequins.  Boxer crabs, the last of Seraya's famous crustacean triumvirate, can sometimes be found by searching under the smooth rocks and pebbles in the shallows at night.  These tiny, pugnacious crabs grasp a pair of anemones in their front claws, waving them at anything they perceive as a threat, including divers.




Like any location, animals come and go and none of the above are guaranteed.  However, Seraya does have plenty of other critters to be found.  Bumble bee and Tozeuma shrimps are seen, particularly in places with more encrusting life on the bottom, whilst fire urchins in the deeper sections are home to Coleman shrimps, zebra crabs and small commensal shrimps that resemble squat lobsters.  There are cleaning stations at both Seraya Secrets and Noisy Reef with huge amounts of hingeback and banded cleaner shrimps, pretty much every crinoid seems to have a resident shrimp or squat lobster, the anemones have porcelain crabs and transparent commensal shrimps and there are huge numbers of decorator and sponge crabs to be found at night.  Nudibranchs seem especially diverse and many different species can be seen on a single dive, especially amongst the rocks and small boulders in the shallows at the end of a dive.  Thorny seahorse, pygmy seahorse, including the unusual orange-yellow form of H. bargibanti, pipefish and ghost pipefish are normally present, and there are normally plenty of boxfish, filefish, bright orange juvenile pufferfish, leaf scorpionfish, devil scorpionfish, frogfish, snake eels, different garden eels, sand divers and gobies - even Rhinopias have been seen.  Mimic octopuses are occassionally spotted here, however small cuttlefish and reef octopus are common and at night, bobtail squid can be spotted out on the sand.




Across the whole site, the eastern end - Seraya Secrets itself - does tend to have the greatest concentrations of critters, perhaps because of its proximity to the river mouth and the lack of cover here.  The Noisy Reef end of the site makes up for fewer muck species with its greater variety of reef fish and beautiful corals that can be found in the shallows.  Overall the entire Seraya area is a fantastic critter site with lots to offer.  It can get busy at times with divers from the local resorts, Tulamben and day trippers, and as a result, the site probably has fewer critters than when it first found fame.  But it still has a huge amount to offer and ranks as one of the best places in Bali for spotting unusual crustaceans such as tiger shrimps, boxer crabs and harlequins.