egularly collected
by fishers, mainly for domestic consumption. The
loss of critical stocks of sea cucumber is likely to
have a significant impact on the ecosystem condition
and the adjacent marine environment, as a
whole. Therefore, there is an urgent need for developing
a technology for seed production and culture
of sea cucumbers in Mauritius. Although
about 1400 species have been identified worldwide,
there is little information about holothurian
species in Mauritius. Conand (1998) mentioned 11
edible species in the southwestern Indian Ocean region,
including Mauritius. Luchman et al. (2001)
carried out a study to assess the distribution and
abundance of the holothurians in the lagoon at
Preneuse (west coast) and in Baie du Cap (south
coast) in Mauritius. The dominant species of sea
cucumbers found in Mauritian waters are the
chalkfish, Bohadschia marmorata and the lollifish,
Holothuria atra. Among these two species, B. marmorata
has a better commercial value and grows to
a larger size (2.0 kg) than H. atra (1.5 kg).
Hence, the present work was undertaken in order to
develop appropriate technologies for the breeding,
seed production and culture of the two species of
sea cucumbers, B. marmorata and H. atra. The results
obtained are presented and discussed in this paper.
Materials and methods
The work was carried out at the Albion Fisheries
Research Centre, Mauritius. Sea cucumber broodstock
were collected from the wild at low tide, and
stocked in 1-tonne tanks filled with a sandy substratum
of six inches thickness to enable the sea cucumbers
to bury in the sand. The water in the tanks
was changed everyday and sand was changed
every fortnight. Fresh seaweed was ground into a
paste in a mixer and put in water at least twice a
week. The sea cucumbers thrived on the organic
matter present in the mud. The algal paste settled
to the bottom and was consumed by the sea cucumbers
along with the mud. Fifteen to twenty
adults were kept in each tank. The methods used
for inducing spawning in these two species of sea
cucumbers are described below.
i) Thermal stimulation: The temperature of the seawater
was reduced by 3–5°C by the addition of ice,
and the sea cucumbers were then introduced into
this tank. After 5 minutes, the sea cucumbers were
introduced into another tank filled with filtered
seawater at normal temperature (3–5°C higher
than the first tank temperature). A rise of 3 to 5°C
was enough to induce spawning. The males
spawned first, which induced the females to release
their eggs.
ii) Stimulation through drying and powerful jet of seawater:
This method was used with breeders that
were conditioned for more than one week in the
hatchery. The sea cucumbers were dried in the
shade for 30 minutes. Then, the specimens were
subjected to a powerful jet of seawater for 30 minutes.
After 1–1.5 hours, the specimens began to
move up the tank wall and began to show swaying
movements. The males released the sperms first
and then, 30 minutes later, the females started reacting.
The anterior region of the female became
bulged due to the inside pressure. The eggs were
released in powerful jets intermittently.
The success achieved for B. marmorata and H. atra
in inducing spawning and larval rearing are described
separately.
Induced spawning and larval rearing of the sea cucumbers,
Bohadschia marmorata and Holothuria atra in Mauritius
A. Laxminarayana1