1. Introduction
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Ž Farmers of mud crabs Scylla species rely on small crabs or juveniles 4–30 g,
. 18–4.0 cm carapace length; CL sourced from intertidal flats and mangroves to stock
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grow-out ponds. However, smaller crabs 0.5–5.0 g; 1–2 cm CL can be nursed for 1–2 Ž
. weeks in net cages prior to stocking in grow-out ponds SEAFDEC, 1997 . With the
increasing demand and declining supply of crab seed, hatchery-reared seed provides an alternate source. Since 1998, researchers of the Aquaculture Department, Southeast
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Asian Fisheries Development Center SEAFDECrAQD have been consistently produc- ing mud crab juveniles in the hatchery. There is, however, low survival due primarily to
the occurrence of luminescent vibrios at the late zoea and megalopa stages, and at the juvenile stage due to cannibalism.
Recently, SEAFDECrAQD researchers successfully cultured hatchery-reared mega- lopae to juveniles in net cages installed in brackishwater ponds for 4 weeks. The
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survival and growth rates achieved were greater in ponds 35–53; 2.9–3.4 g than in Ž
. hatchery tanks 25–35; 0.70–2.5 g; shooters not included . The culture of megalopae
to juveniles in ponds could be a promising alternative to growing them in tanks. With this development, handling and transport of megalopae need to be included in routine
stock transfer activities in the hatchery.
Handling, packing, and transport activities expose the animals to stress. Crab juveniles are relatively easy to transport by using a wicker basket, a native straw
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‘pandan’ bag or carton lined with moist mangrove or leaves or cheese cloth. Chelae Ž
. are tied or cut to prevent fighting among crabs Ladra and Lin, 1991 . In air, mud crab
has a life span of 2–18 days when packed with moist marine algae, cotton, or wood Ž
. shavings Vasudeo and Kewalramani, 1960 . We observed that megalopae are more
sensitive to handling, packing, and transport than juveniles. The optimal conditions during transport of megalopae needed to be determined to reduce mortalities.
This study considered the optimal loading density at various durations of transport of hatchery-reared Scylla serrata megalopae. Various temperature levels were also tested
to determine the effect of cooling on the survival of megalopae. The taxonomic Ž
. classification of the species S. serrata used in this study is based on Keenan et al.
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1998 .
2. Materials and methods
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