Shipping studies with juvenile and adult Malaysian prawns Macrobrachium rosenbergii (de Man)

Abstract Four studies examined shipping factors of packing technique, density, duration, type of water and use of habitat material for shipping juvenile and adult prawns Macrobrachium rosenbergii . Prawns were shipped in double polyethylene lined 38 × 38 × 20 cm deep styrofoam boxes containing oxygenated water. At temperatures of 19–20°C, 17 g prawns could be shipped safely for 42 h at a density of 10–12 prawns per box (12–15 g liter −1 shipping water). Juveniles, mean size about 6 g, could be shipped at a density of 40 per box (18 g liter −1 ) for 24 h or 20–25 per box (9–11 g liter −1 ) for 48 h. Use of mesh material to increase surface area in the box did not appear beneficial nor did shipping in brackish water (salinity⩽8‰). Adults packed unrestricted resulted in survival rates substantially higher than those obtained from immobilized prawns wrapped in mesh. During the shipment, pH and dissolved oxygen concentrations decreased whereas ammonia concentrations increased. The decreased pH levels may have reduced the ammonia toxicity by decreasing the amount of toxic unionized ammonia (NH 3 ) in solution. In general, dissolved oxygen concentrations appeared more closely related to survival rates than did other water quality parameters which were measured.