COMMON NAMES: Sandfish (FAO), Sand (Egypt), Ñoät traéng (south Viet Nam), Hải sâm

trắng, Hải sâm cát (central Viet Nam), Vella attai, Cheena attai (India), Sandfish (Mauritius,
Papua New Guinea, Australia), Putian, Cortido, Curtido, Kagisan (Philippines), Hedra beyda
(Eritrea), Zanga fotsy (Madagascar), Jongoo mchanga (Tanzania), Myeupe (Zanzibar,
Tanzania), Dairo (Fiji), Le gris (New Caledonia).
DIAGNOSTIC FEATURES: Colour variable; in the Pacific Ocean and Southeast Asia, it can
be black to grey or light brownish green, sometimes with greyish-black transverse lines. In
the Indian Ocean, it is usually dark grey with white, beige or yellow transverse stripes.
Ventral surface is white or light grey with fine, dark spots.
Body oval; arched dorsally and moderately flattened ventrally. Dorsal surface with deep (3
mm) wrinkles and short (1.5 mm) papillae. Body is often covered by fine muddy-sand.
Mouth is ventral with 20 small, greyish, tentacles. Anus is terminal with no teeth. No
Cuvierian tubules.
Ossicles: Tentacles with spiny rods, 80–440 μm long, slightly curved. Dorsal and ventral
body wall with tables and buttons.
Ventrally body wall: tables are rare, disc between 60 and 95 μm across, quadrangular and
with smooth rim, perforated by 1 central and 8–16 peripheral holes, spire ending in crown of
blunt spines; numerous buttons are 40–75 μm long. Dorsally body wall, similar tables,
butsmaller; buttons are 40–50 μm long. Ventral podia with nodulous buttons, 40–90 μm long,
perforated rods, 110–170 μm long, and tables as in body wall. Dorsal papillae present few
rods, few tables, but many buttons as those in the body wall.
Processed appearance: Cylindrical with bluntly curved ends. Coloration from dark tan to near
black; ventral surface usually amber-brown. The dorsal surface retains the deep transverse
wrinkles. No cuts or small cuts across mouth. Dried specimens 10–15 cm for top grade sizes.
Remarks: The golden sandfish, Holothuria lessoni, was previously regarded as a variety of H.
scabra. Recent integrative taxonomic study (Massin et al., 2009) has however clearly
separated both species. Whether the Indian Ocean form of H. scabra also represents a
separate species remains to be investigated.
Size: Maximum length about 40 cm; average length about 24 cm. Maximum weight 2.0 kg;
average fresh weight: 300 g (Papua New Guinea, Oman, India), 335 g (Australia), 500 g
(Egypt), 580 g (New Caledonia); average fresh length: 19 cm (Australia), 20 cm (New
Caledonia, Oman), 22 cm (Papua New Guinea), 25 cm (India), 37 cm (Egypt).
HABITAT AND BIOLOGY: Found in shallow waters, but occasionally to about 20 m.
Commonly found on inner flat reefs of fringing and lagoonal reefs, and coastal sandflats and
seagrass beds with muddy sandy substrates, near mangroves. Both adults and juveniles bury
in sand and sandy-mud at some localities. Attains size-at-maturity at 21 cm in Mauritius, at
about 25 cm in India and northern Australia and at 16 cm in New Caledonia.
The use of sea cucumbers as a food item and a commodity began in China about 1 000 years
ago, which encouraged the development of capture fisheries in the region. However, the
rising demand of the markets in Asia led to the depletion of local sea cucumber populations
and prompted Asian traders to solicit sea cucumbers from locations further afield (Conand,
2004, 2005b; Bruckner, 2006; Toral-Granda, Lovatelli and Vasconcellos, 2008; Purcell,
2010). Currently, sea cucumber fishing occurs all over the world with some populations
reportedly over-harvested (Lovatelli et al., 2004; Bruckner, 2005b; Uthicke and Conand,
2005; Conand and Muthiga, 2007; Toral-Granda, Lovatelli and Vasconcellos, 2008). Most
tropical fisheries are multispecific and at an artisanal scale or for subsistence use. In some
cases, fishing evolved to target many low-value species after stocks of the more valuable
species were depleted. In temperate regions, fishing commonly focuses on one species
harvested with industrial fishing methods (Hamel and Mercier, 2008). The vast majority of
species are harvested for the ‘bêche-de-mer’ or ‘trepang’ market (e.g. Actinopyga mauritiana,
Holothuria scabra, Thelenota ananas), although some species are also consumed cooked,
pickled or raw (e.g. Apostichopus japonicus, Cucumaria frondosa, Parastichopus
californicus). Some domestic markets also demand the pickled intestines and gonads, while
some commercial products have sea cucumber by-products (e.g. “gamat” oil from Stichopus
horrens) and others are included in the aquarium trade. Generally, sea cucumber harvesting is
for export, with little domestic use, and the market is largely driven by oriental entrepreneurs
who set the price for the sale (Conand, 2008; Kinch et al., 2008; Toral-Granda, 2008).
Since the 1980s, sea cucumber harvesting has boomed but many stocks have collapsed.
Concomitantly, fishers in more and more countries are exploiting more species in an attempt
to meet the strong demand in Asian markets. Towards the end of the “boom” part of a
“boom-and-bust” fishing cycle, populations of some species had been reduced to such low
levels that there was little capacity for natural recovery and replenishment, leading to their
economic and ecological extinction. Sea cucumbers belong to the class Holothuroidea and so
are also referred to as holothurians. The majority of species harvested commercially belong
to the order Aspidochirotida, specifically to the families Holothuriidae and Stichopodidae,
and are mostly tropical. A few species belonging to the order Dendrochirotida, family
Cucumariidae, are also fished commercially. Species in the orders Apodida,
Dactylochirotida, Elasipodida and Molpadida are mostly not fished commercially and are not
presented in this field guidebook. Conand (2006) recognized about 40 species of sea
cucumber under commercial harvest, while Toral-Granda, Lovatelli and Vasconcellos (2008)
listed at least 47 species. Later, Purcell (2010) lists 66 species that are currently exploited
commonly in various regions of the world. The chronological increase in the number of
reported exploited species echoes the pervasive problem of serial depletion of high-value
species, leading to exploitation of new species. The taxonomy of some groups of sea
cucumbers is complex, even for taxonomic experts, and has stimulated much research in
recent years. Uthicke, Byrne and Conand (2010) genetically analysed the relationships among
many commercial species, shedding new light on a few of them. However, once processed,
some sea cucumbers can be difficult to identify to species level, creating a problem for trade
officials. This has been identified as a bottleneck when attempting to implement conservation
tools in the international trade (e.g. a CITES listing) and has led to the development of illegal,
unreported and unregulated (IUU) trade.