by Clifford Young

ANYONE who has spent some time wading across shallow reef flats, particularly in warm, northern waters has probably seen a sea cucumber or two. However, before you rush out to collect a few for your next lunchtime salad, be warned that names can be deceiving.

For starters, the sea cucumber is an animal, not a vegetable, and although some varieties are dark green, they are more commonly dark red-brown or even black in colour. The general shape is reminiscent of its namesake, but most people would agree that it looks more like a slightly warty slug than a tasty vegetable.

Having read all that, it may come as a surprise that the sea cucumber is a prized food, particularly on Asian markets, where it fetches good prices - but not for use in salads! Instead it Is sold in a smoked, dried form and is sought after for use in soups and, according to some reports, as an aphrodisiac.
In its prepared form it is known as trepang or béche-de-mer and, earlier this century and through much of the nineteenth century, the animal was the basis of a major export industry across northern Australia.

The fishery itself goes back even further in time. Matthew Flinders sighted a fleet of 60 Indonesian vessels collecting béche-de-mer in the Gulf of Carpentaria while charting the Australian coast in 1803, and there is substantial evidence that the activity has been carried on since Macassans from South Celebes first visited Australia around 1700.

Although about 200 species of sea cucumber have been recorded from Australian waters, only a few large tropical species were collected for processing as béche-de-mer. The process itself involved boiling the body in salt water, gutting it, smoking it and finally sun-drying it. The finished product is hard, dry and a fraction of the weight of the live animal.

Interestingly the sea cucumber is closely related to sea urchins and starfish, although its hard to see the resemblance at a glance. Their hard calcareous skeleton, reduced to microscopic spicules, is buried under the skin.
Some sea cucumbers can expel sticky white threads to entangle or distract would-be predators, and some even expel their internal organs when disturbed. Amazingly the organs can be regenerated and life for the animal will go on normally. Worldwide, their body sizes vary from two centimetres to 200 cm, and thicknesses between one and 20 cm. They are found in all oceans, mostly in warm shallow waters, but sometimes at great depths. However they are most common in the Indian Ocean and the South West Pacific.

They tend to be most conspicuous in the tropics where they can be found lying scattered over the sandy parts of coral reef flats, among corals and under boulders.

Their mouth, which is at one end of their body, is surrounded by a crown of between 10 and 20 retractable tentacles. These tentacles can be used to trap passing plankton or, depending on the species, used to sweep up the sandy mud in which they live. The mud is swallowed, the food particles removed, and the sand is passed out through the body.

Sea cucumbers move in a slug-like manner, using a series of little tube feet. Some of them are soft and flaccid but others are quite tough and leathery.

Although there is still considerable demand for beche-de-mer throughout much of Asia, there is very little commercial fishing for it in Australia today. The local industry wound down in the late 1940's largely because of lesser demand and poor prices.

In Wester Australia, most of the catch comes from the North West shelf.
Above article reprinted from Western Fisheries Magazine Archive.

For a review of the angiogenic properties of sea cucumber extract, click here.