Crabs of all shapes and sizes roam the fringes of Pulau Sekudu, from the rocks that tower over slopes of rubble to the wave-lapped contours of an islet that is too big to sink, too small to be settled and far too old to be of any good to a youngling nation. Parts of the shore are firm and covered by a layer of coarse rubble, on which sponges, sea anemones and tube worms have taken hold. Snapping shrimp maintain tunnels under these outcrops, which also harbour sundry hunters – toadfish, eel blennies and octopuses – with bright eyes and big appetites. Other stretches of the flat are soft enough to suck in your heels, turning each step forward into a plunge through silt, weed and scum. The substratum is hidden by clumps of Ulva, porous tangles in which tiny crabs, ophiuroids, segmented worms, amphipods, biscuit stars, nemerteans, hermit crabs and living shells graze, grapple and grind their teeth against even tinier filaments and forms of life invisible to the tired eye.
Formless chunks of grey, the refuse of carpet anemones, worm poo and deshelled fragments, litter the green, clouding the line between mere debris and living mass. Elbow crabs are among the many pretenders on this stage of slow acts; tiny individuals, tossed by tidal swings and microwaves, are scarcely distinguishable from random gunk, but larger animals may find themselves betrayed by their joints, which jut out far from their carapace in repose and support, in defiance, palms that are held wide apart, in the manner of thomisids, ready to deliver a discouraging nip. Though restricted in their degree of movement, their claws offer reach and the means to pick apart small prey – worms and molluscs that are secured by a chela with stout digits and crushed by a robust tooth on the other hand.
Parthenopids, having profiles that resist popular mental images of brachyurans, usually escape notice as they feed amid benthic scraps. Females lose their cloak when in berry, however, for the sponge beneath their belly would perish if smothered by muck. The blessing, or brunt if you will, of their infraorder, decapods that have traded length of body for breadth and bulk, and turned tail into nursing tool, is an abdomen that in degeneration has to be held against the sternum with the aid of specialised muscles, coxal spines or a 'press button' mechanism, in which a sternal tubercle locks onto a socket on the sixth ventral segment. The latter is an adaptation that allows crabs to keep the box closed, as it were, and their gonopods out of harm's way, without incurring muscular tension. Females, whose abdomens are much wider than their mates' and often strongly fused to function as a lid, usually lack the bouton-pression, but in a few families, such as Dorippidae and Parthenopidae, both sexes possess the lock.
The hinge must be loosened in mated females, who bear the burden of parenthood and cease to moult while in berry, when they extrude their eggs, which are fertilised by stored sperm as they pass down the oviduct. The brood then attaches to the female's exposed pleopods, which have lost their ancestral ability to paddle and now serve as hairy branches on which they are ferried, aerated and guarded until they hatch. The eggs, numbering from thousands to millions depending on the girth of their mother, are initially orange or khaki, but as they mature, each ovum doubles in size and fades to brown then black as the yolk is consumed and a zoea with visible eyes takes shape. The female, by then compelled to walk on tip toe to accomodate a swelling mass of embryos, then releases the larvae with crabby twerks timed to catch the tide at its strongest, so that ebbing waters convey her babies away from hostile shores.
Other crabs were also in season at Pulau Sekudu. An ovigerous Portunus pelagicus shimmied over the seagrass, her hind segments clearly detached and harbouring a distended package. Not a few stone crabs, caught in midsupper or en route to their morning retreats, stood tall, brought low by the roe between their legs. And a purple climber crab, only a little more apparent than usual due to her elevated poise, clung to a wall of sticky hides, skirting soft blobs and shiny coils as she nursed the fruit of her labour, still far from ripe and for now, beyond the grasp of a straits filled with hungry mouths and greedy minds.