| Naga
- The *ICLARM Quarterly
Vol.
22, No. 4 (October - December 1999)
Features
Tropical
Sea Cucumbers for Stock Restoration and Enhancement
S.C.
Battaglene
Abstract
Severe
overfishing of sea cucumbers has occurred in most
countries of the tropical Indo-Pacific. The release
of cultured juveniles is being examined at the
*ICLARM Coastal Aquaculture Centre (CAC) in the
Solomon Islands as a means of restoring and enhancing
tropical sea cucumber stocks. Sandfish (Holothuria
scabra) are the tropical species that show
the best potential for stock enhancement. Sandfish
are of high value, widely distributed and relatively
easy to culture in simple systems at a low cost.
This paper summarizes information about the culture
of H. scabra and compares it to that of
the temperate species Stichopus japonicus.
Sandfish live in high nutrient environments at
densities of 100s per ha. They have a reproductive
peak in September and October, but can be induced
to spawn throughout the year. Increases in water
temperature and addition of powdered algae are
effective ways of inducing spawning. Chaetoceros
muelleri and Rhodomonas salina are
two of the better microalgae for feeding the larvae.
Sandfish larvae are more robust and easier to
rear than those of other tropical species. Larvae
metamorphose into juveniles after two weeks at
28°C and settle on diatom conditioned plates.
The CAC has produced over 200 000 juveniles from
six separate spawnings. Sandfish can be reared
on hard substrata until they reach 20 mm in length
and are then best transferred to sand substrata.
Absolute daily growth rates for juvenile sandfish
average 0.5 mm day -1 (±0.03 s.e.) and range
from 0.2 to 0.8 mm day -1, depending on stocking
density, light intensity and addition of powdered
algae. Overall, there are good reasons to believe
that sandfish can be produced cost-effectively
for restocking and stock enhancement. The potential
for using cultured juveniles to manage fisheries
for sea cucumbers now depends on the development
of strategies to optimize the survival of juveniles
released into the wild and to evaluate releases
on a commercial scale.
S.C.
Battaglene is with the International Center for
Living Aquatic Resources Management (*ICLARM),
Coastal Aquaculture Centre (CAC), PO Box 438,
Honiara, Solomon Islands.
Hatchery
and Culture Technology for the Sea Cucumber, Holothuria
scabra Jaeger, in India
D.B.
James
Abstract
The
seed of the sea cucumber Holothuria scabra
Jaeger is being produced at the Central Marine
Fisheries Research Institute in India. This article
describes the techniques being used in the production
of the seed and the experiments being carried
out for the rearing of juveniles. Trials to grow
juveniles in hatcheries on prawn farms have shown
spectacular results that are both cost efficient
and environmentally friendly.
D.B.
James is a Senior Scientist at the Research Centre
of the Central Marine Fisheries Research Institute,
Tuticorin-628 001, Cochin, India.
Volunteer
Sports Divers: A Valuable Resource in the Management
of Bahrain’s Fisheries
K.R.
Uwate and J. Al-Meshkhas
Abstract
The
Directorate of Fisheries (DOF) of Bahrain has
a novel scheme in which the DOF workers cooperate
with local sports divers in the management and
conservation of their marine resources. This cooperation
is mutually beneficial for both the DOF and the
divers who are interested in environmental conservation.
K.R.
Uwate is currently the Advisor to the Director
of Fisheries, Bahrain. He coordinates volunteer
dive trips for the DOF while J. Al-Meshkhas is
an Officer of the Bahrain Diving Committee and
coordinates volunteer divers for this joint project.
 |
