Breeding and nursery culture of sebarau, Hampala macrolepidota (Van Hasselt and Kuhl, 1823)

Hampala macrolepidota or locally known as sebarau, is a native carp species of Malaysia, yet not a popular fish for aquaculture. This may be due to the lack of seed supply and proper nursery culture technique. This study was aimed to breed H. macrolepidota using Ovaprim, to observe its embryonic stages and to determine the effects of different salinity, pH, dietary protein and stocking density on the growth and survival of its fry. For the first objective, induced breeding of H. macrolepidota was carried out with injection of 0.6 and 0.3 ml Ovaprim kg-1 female and male, respectively. Results from the induced breeding shows that, H. macrolepidota with weight ranged from 180 - 280 g was able to produce 243,418 eggs/kg female. Mean of egg diameter for H. macrolepidota was 0.80 mm, while percentage of eggs fertilization was 22 % with majority of the eggs hatched within 24 h after fertilization. Embryonic development of H. macrolepidota lasted for about 24 h. For the second objective, H. macrolepidota fry with initial body weight ranged from 0.35 – 3.00 g were used for experiments on salinities and pH for a period of 6 weeks. These experiments were conducted with 4 treatments (0, 5, 10 and 15 ppt) and pH also with 4 treatments (6.0, 6.5, 7.0 and 7.5). In both experiments, growth performance (weight and length increments) was determined through weekly sampling. Meanwhile survival and water quality were monitored throughout the study period. The highest percentages of survival for fry at salinity 0 -10 ppt and pH 6.0 -7.5 were 96.67% and 51.67%, respectively. Statistical analysis showed no significant differences (p>0.05) for survival, weight and length increments between all the treatments. The highest body weight and total length value were from salinity 0 ppt with the value of 2.50 g and 6.02 cm. As for pH experiment, there were slight differences for weight and length increments during the first three weeks of culture, however no significant differences (p>0.05) were observed toward the end of the experimental period. The highest body weight value, 1.24 g was from pH 7.0 and highest total length of 5.00 cm from pH 6.0. The findings of this study showed that H. macrolepidota fry were unable to tolerate salinity above 15 ppt, while able to grow well in water with pH ranged from 6.5 to 7.5. Finally, the third objective, experiments were conducted for 6 weeks to examine the effects of different dietary protein and stocking densities levels on the growth of H. macrolepidota fry with initial body weight ranged from 0.2 – 2.0 g. Dietary protein experiment was conducted with 3 treatments (23, 32 and 42% protein level) and stocking density also with 3 treatments (3, 4 and 5 fry/L water). In both experiments, survival and water quality were monitored throughout the study period and growth performance (weight and length increments) was determined through weekly sampling. For the dietary protein experiment, pellet with 32% protein produced the best growth performance for H. macrolepidota fry as compared to pellets containing 23 and 42% protein. Fry fed with pellet containing 23% protein showed the highest percentage of survival (76.67%). While fry fed with 23 and 32% of protein pellet showed significantly higher (p<0.05) specific growth rate (SGR) than those fed with 42% of protein. In term of feed conversion ratio (FCR), fry fed with 23% protein pellet showed significantly higher (p<0.05) FCR than those fed with 32 and 42% protein content. Fry fed with 32 and 42% showed significantly higher (p<0.05) protein efficiency ratio (PER) than those fed with 23% protein. As for proximate composition of the feed, no significant difference (p>0.05) were observed for crude fibre, moisture and energy between treatments except for the crude protein, ash and NFE. For lipid, pellet with 23 and 32% of protein showed significantly higher (p<0.05) lipid content than pellet with 42% protein content. As for stocking density experiment, 3 fry/L showed the highest percentage of survival (100%). However, there was no significant different (p>0.05) between all the treatments. The highest body weight and total length was observed in fry stocked at 5 fry/L. Slight differences were observed in body weight during the second week of culture and in length increments during the first week of culture. However, no significant differences (p>0.05) were observed between treatment for the first week (body weight) and towards the end of the experimental period (body weight and total length).

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