BALI BEACHCOMBING
A Naturalist's Guide to Surf ' Sand and Sea

Virtually all visitors to Bali spend some time at the beach - wandering along baking strips of sand watching bathers, surfers and sun worshippers, or even lying prone absorbing the sun's UV rays (something the Balinese wouldn't think of doing!). Few visitors, however, appreciate the natural interest that is all around them as they stroll toward the sunset, moan under a masseuses' fingers or paddle in the shallows. For those who feel a bit bored with normal beach activities, the following is a brief guide to beach combing from a naturalist's point of view.

The cool, early morning when the disco crowd is still in bed is a good time to look for interesting items washed up during the night. This is also when Bali's feral dogs congregate on the beach awaiting the first life-sustaining offerings of rice from the faithful. The dogs' fight and amours are typical of wild carnivores and the leaders, wimps and sneaks can all be identified.

Time and the tides

The beachcomber's most important tool is a tide table - distributed free by surf shop such as Tubes, on Poppies Lane Il in Kuta. These let you identify the rewarding period of relatively low water, when surfers mope about wondering what to do or watch surfing videos but beachcombers are out in force.

The most common beachcombing activity is shell collecting, and a wonderful variety can be found here - we have found 30 different species along Kuta Beach and nearly 50 at Sanur. Empty shells washed up on the beach may have been tumbling around in the water for a long time but many are still beautiful glossy.

The shells offered for sale in street stalls and by wandering vendors are in very good
condition because they have been collect live in other parts of Indonesia (those from
around Bali were sold long ago). Some of the larger shells are protected by law and the clams are now also protected by international convention. Customs will not be pleased to find clam shells among your souvenirs.

The beaches of Bali show considerable variation, and one of the most obvious is in the sand itself. Around Kuta the sand is a mixture of coral and shell fragments mixed with gray volcanic ash washed down from the mountains by the rivers. At Nusa Dua and Sanur it is a pale golden color without any ash, and many sand particles are quite large.

A closer look reveals that many of the larger particles are rounded tetrahedrons, with four evenly-spaced points. These are skeletons of single-celled marine animals called foraminiferous. A little way offshore they can be found in huge numbers attached to various aquatic plants, where they filter small organic particles out of the water. The skeletons of these "forams" (as they are known to the cognoscenti) do not pack closely even when wet, and this is why walking along the upper levels of Sanur Beach is so tiring and motorcycling is impossible, whereas Kuta with its hard packed, small-particle sand is a jogger's and motorcyclist's dream.

Kuta Beach

The striking thing about the sea at Kuta is its energy - the waves break close to shore and there is a long tidal reach, so the shore is heavily scoured. Few organisms can cope with the heavy surges of water. But wander along Kuta Beach at low tide and you'll notice what look like the five-pad footprints of a large dog, but not arranged in tracks. Brush away the sand and just beneath the surface You will find Sand Dollars (Echinodiscus bisperforatus), relatives of the sea urchins. Their flat shape offers minimal resistance to the moving water and hundreds can be found in a short walk.

Another conspicuous creature is the abundant kremis shell (Donax cuneata), only about 1 cm long and in various colors: gold, purple, white and red. The waves uncover these bivalves when they are just below the sand but their white "foot" drags them into the sand again, sharp end first, leaving the flattened end topmost. At the end of the day, when bodies beautiful and otherwise have retired to the showers and bars, the beach masseuses can be found collecting the kremis. They're good to eat, if fiddly, and the water they are boiled in makes a good soup. Much less abundant is the so-called "common" Olive Shell (Oliva oliva) which is about 2 cm long and has a shiny, brown-patterned shell. This moves just below the sand's surface and its winding tracks are quite conspicuous as it searches for and eats the kremis.

When the tide recedes, tiny Bubbler Crabs (Scopimera) emerge from their burrows, as many as 100 per square meter. They feed on minute organic particles in the sand, rolling the processed sand away from their holes in roughly concentric circles around the burrow entrance. When the tide creeps up again the sand is covered with these tiny balls. As the water reaches their burrows, the crabs busily push small domes of sand over the entrances, sealing the air in against the rising tide.

Much larger burrows found higher up the beach belong to Ghost Crabs (Oxypode) which venture onto the beach foraging for organic goodies at the water's edge. Two aquatic crabs may nibble at your toes while paddling - the small (less than 5 cm) Moon Crab (Matuta lunaris) with broad paddles at the tip of its legs, and the larger Flower Crab (Portunus pelagicus) with long arms and paddles on only the last pair of legs. These paddles are used both for swimming and for digging just below the sand surface, where they generally hide during the day. Both have long and very sharp spines jutting outward from the sides of their bodies. They feed on small fish, shellfish and worms.

Their empty shells can often be found stranded on the beach, but these are usually moulted skins rather than the remains of dead animals. Kuta is also the best tourist beach to see seabirds. Black, angular-winged Greater Frigates (obtusely named Fregata minor) soar effortlessly on unmoving wings in groups of up to 20 individuals. Small white terns dance above the water, picking up unwary fishes, while grayish Brown Boobies (Sula leucogaster) sometimes fly in a very determined manner parallel to the coast.

Sanur Beach

The waves at Sanur break over a reef crest several hundred meters from the shore. As a result, only small and gentle waves reach the beach, and this protected lagoon is a very rewarding area biologically.

Between the beach and the reef are some of the best sea grass meadows a casual visitor is likely to see, and it is worthwhile idling a while in this area. Sea grass is thought of as a weed, since the commonest encounter with it is when the broken or rotting leaves get caught in your hair while swimming. Indeed, staff of the large hotels can be seen at dawn busily sweeping this natural frass into holes or trucking it away lest sensitive visitors feel their idyllic beach is despoiled. The sea grass meadows can be explored either by walking around wearing sneakers at low tide when the water reaches only slightly over the ankles, or by snorkeling at high water.

There are at least five species of sea grass present, with the most abundant, Enhalus acoroides, having broad, strap-like leaves and black hairy rootstocks. These roots would once have been eaten by dugongs or sea cows which doubtless swam slowly across this lagoon in former times. The meadows are highly dynamic but much of the growth, in the system is actually in the thin carpet of fine and fuzzy algae and other organism growing on the plants' leaves, which are grazed by fishes, mollusks and other an m, Don't forget to look for the living "forams" on and around the bottom of the sea grass stems and among the various types of algae which grow in the vicinity.

Most of the animals in the sea grass mead owe are grazers feeding on the algae rather than the sea grass itself. More or less the only animal that eats sea grass leaves is the Green Turtle (Chelonia mydas) which still visit Sanur to feed, but no longer to lay eggs.

Also among the sea grass you will find numbers of large, knobby starfish (Protore aster nodosus), occuring in a variety of color orange with red knobs, blue with green, grey with pink, and so on. A smaller and less robust species is Aster typicus, an enormous mating orgy of which we once found unnoticed by others just in front of the Hyatt Hotel A third species, Culcita schmidmeliana, is rounded and has five sides rather than arms and looks like a discolored cauliflower.

It is not uncommon while walking around at low tide to see dense clumps of small (5-10 cm) black-lined catfish (Plotosus lineatus) which swim so close to one another that one could be excused for thinking at first that the black mass was a single organism, and it may be that potential predators are similarly duped. Each clump seems to have individuals of one size that may have come from the same mass of eggs.

Urchins and cucumbers

The black sea urchin Diadema setosum is a relatively common sight with its long, slender spines which enter human feet with ease, but then break off and resist removal to the accompaniment of great pain. They do not, however, attack and a close look reveals beautifully delicate spines with a very bright red ring around the upward-facing anus and the adjacent bright blue genitals. In polluted waters these grazing animals form dense plagues, and it is more thanks to the strong current and a natural restorative proclivity than environmental awareness that Sanur's reefs and meadows are as fine as they are and that these urchins occur at such relatively low densities.

You might occasionally see a Banded Sea Snake (Laticauda colubrina) in the meadows; although its venom is highly toxic, it is reluctant to bite unless unbearably provoked. A beast which can be mistaken for a snake by the naive beachcomber is the weird sea cucumber Synapta maculata. This, too, is long (up to 2.5 m), thin, striped and lurks among the sea grass, but it is limpid, ribbed and has a feathery mouth that protrudes from its head (they only way to tell which end is which). Other common sea cucumbers are the black Holothuria atra to which grains of sand adhere, and Stichopus variegata which looks for all the world like a freshly-baked loaf of whole meal bread.

Back at the water's edge, particularly on weekend afternoons, one can see people bent double, sprinkling rice water onto the wet sand, staring earnestly at it, and occasionally grabbing at something with thumb and forefinger. A slow, steady pull reveals a 10-20 cm rag worm (Perinereis), much prized as bait by weekend fishermen. These secretive animals can also be tempted to the surface with delicacies such as soggy bread, fish soup or very dilute shrimp paste.

The more time one spends at the beach the more one sees. Get out there and explore, but please leave five shells and other animals where you find them!