TRANSPORT OF SCYLLA SERRATA MEGALOPAE AT VARIOUS DENSITIES AND DURATIONS

E. T. Quinitio, F. D. Parado-Estepa-2000

Aquaculture, 185 (1-2): 63-71
Abstract :

The optimal conditions for transport of Scylla serrata megalopae were determined. Loading densities of 50, 100 and 150 ind/l of hatchery-reared megalopae were studied over a 6-h simulated transport, including shaking. Survival immediately after transport was significantly higher at 50 ind/l (99.3 +/- 1.6%) (mean +/- x%) than at 100 (93.0 +/- 5.0) and 150 ind/l (94.0 +/- 3.8%). The same trend was noted 15 h after transport. Another experiment compared survival of megalopae packed at 50 and 100 ind/l with simulated transport of various durations (3, 6, and 9 h) at mobile and stationary conditions. Regardless of the duration and condition of transport, survival was again significantly higher at 50 ind/l (86.7 +/- 2.4%) compared to 100 ind/l (79.7 +/- 2.1%). Megalopae that were shaken or remained unshaken for 3 or 6 h had similar survival through transport as those shaken for 9 h. Megalopae that remained unshaken for 9 h gave the lowest survival among treatment groups (38.7 +/- 0.2%).

Due to cannibalistic behavior, stationary transport conditions may have provided the megalopae with a chance to grasp each other. In a third experiment, a batch of megalopae was packed at water temperature levels of 20, 24, and 28 C (ambient) at 50 and 100 ind/l for 6 h simulated transport, including shaking. Density and temperature separately influenced survival. Survival was lower at 28 C than 24 C. Although megalopae were less active at 20 C, survival was similar to that at 24 C and 28 C. These results provide useful information for megalopae transport from hatchery to ponds.

(Aquaculture Department, Southeast Asian Fisheries Development Center, 5021 Tigbauan, Iloilo, Philippines)

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