Abstract:

This study was carried out to determine the optimal water temperature and to investigate the effects of additional substrate on growth and survival during the nursery culturing of Penaeus semisulcatus in two separate experiments. At the end of six weeks, survivals of postlarvae (PLs) at 22, 24, 26, 30 and 34¡C were 52, 46, 70, 30 and 40%, respectively. The highest (2.76 mm/week) and lowest growth rates in terms of total length (0.43-0.49 mm/week) were displayed by the PLs grown at 34¡C and 22-24¡C, respectively. Growth rates were 1.75 mm/week at 30¡C and 1.03 mm/week at 26¡C. Final individual weight showed a drastic increase (over five times) with increasing temperature level from 22¡C (55 mg) to 34¡C (285 mg). Individual final weights at 22, 24 and 26¡C were not significantly different from each other (P>0.05). Weight gain per week was 432 mg/week at 34¡C and 58-68 mg/week at 22-24¡C. The PLs at 34¡C had a growth rate 6-7 times faster than those at 22-24¡C. Yield at 34¡C (5.7 g) was four times as high as that at 22¡C (1.43 g). The yield at 24, 26 and 30¡C was 1.40, 3.03 and 2.59 g, respectively. Artificial substrate constructed of seine netting to increase habitat area did not improve the survival and growth of postlarvae compared with the control.

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