Effect of hydrogen ion on Macrobrachium
rosenbergii (de Man) egg hatchability in brackish water
A.T. Law, Y.H. Wong, Ambok Bolong Abol-Munafi-2002
Aquaculture, 214(1-4) : 247-251
Abstract:
The effect of hydrogen ion on egg hatchability of Macrobrachium
rosenbergii (de Man) in brackish water was studied. A bioassay using the
artificial hatching of fertilized M. rosenbergii eggs in flow-through
system was employed in this study. The experimental conditions were
set at salinity 12 g/l, temperature 30 °C, DO >5 mg/l, unionized ammonia
<0.025 mg/l, and a pH range between 5 and 10.
The results indicated that M. rosenbergii egg
hatchability is extremely sensitive to hydrogen ion concentration in
brackish water. In brackish water of 12 g/l salinity, the highest hatching
rate was detected at pH 7.0 with value of 92.22±1.72%. At pH 6.5 and 7.5,
hatching rates drastically dropped to 5.00±3.50% and 13.33±2.98%,
respectively. While at pH of 5.0, 8.0, 9.0 and 10.0, the hatching rates were
zero.
This study implies that pH of the brackish water for M.
rosenbergii hatchery operation should be maintained at 7. This will
increase the hatching success of the prawns and reduce the number of brood
stock required for the hatchery operation.
(Faculty of Science and Technology, Kolej Universiti
Sains and Teknologi Malaysia, Mengabang Telipot, Kuala Terengganu 21030,
Malaysia, e-mail: atlaw@kustem.edu.my)