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KONINKLIJKE ACADEMIE VOOR OVERZEESE WETENSCHAPPEN ...

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— 291 —<br />

The results show no statistically significant differences (p > 0.05) in fecundity,<br />

fertilization and hatching rates between pituitary gland hormone concentration<br />

levels of 8 to 12 mg/kg. The mean fecundity fluctuated around 662,689 to<br />

742,045 eggs/kg. The lowest fecundity and fertilization rate obtained<br />

662,689 eggs/kg and 79.3 % respectively which were observed at the hormone<br />

concentration level of 9 mg/kg, and the highest of 731,704 eggs/kg and 93.5 %<br />

respectively were observed at concentration of 1 0 mg/kg.<br />

3.1.4.4. Experiment 2: Nursing Climbing Perch: from Larvae to Fingerlings<br />

— Water Quality Parameters in Nursing Systems<br />

The water quality parameters in all experimental nursing systems are showed<br />

in tables 6 and 7.<br />

Treatment<br />

parameters<br />

Water temper. (°C)<br />

DO (mg/1)<br />

Parameters<br />

Table 6<br />

Water quality parameters for the experiments in concrete tanks<br />

I II III<br />

AM PM AM PM AM PM<br />

27.5 ± 0.8<br />

3.12 ± 0 .5<br />

29.5 ± 0.7<br />

3.58 ± 0.7<br />

28.2 ± 0.4<br />

4.05 ± 0.5<br />

Table 7<br />

29.8 ± 0.4<br />

4.05 ± 0.5<br />

27.0 ± 0.6<br />

4.15 ± 0.8<br />

Water quality parameters for the experiments in earthen ponds<br />

Nursing periods (days)<br />

29.2 ± 0.3<br />

4.00 ± 0.7<br />

3 10 17 24 31 38 45<br />

Water temper. (°C) 29.0 29.5 29.5 30.0 31.0 32.0 30.0<br />

Dis. oxygen (mg/1) 3.44 3.2 2.0 2.64 2.96 3.28 2.08<br />

COD (ppm) 9.2 8 9.6 23.2 23.2 17.6 10<br />

N-NH4* (ppm) 0.16 0.16 1.50 0.21 1.69 1.30 0.06<br />

P-POj' (ppm) 0.06 0.07 0.10 0.45 0.07 0.08 0.06<br />

During nursing periods, the water quality parameters in concrete tanks and<br />

earthen ponds such as water temperature and dissolved oxygen ranged from 27-<br />

29.8 °C, 3.1-4.6 ppm and 29-32 °C, 2.0-3.4 ppm respectively. The concentrations<br />

of chemical oxygen demand, ammonia and phosphorus in earthen pond<br />

system fluctuated from 8-23.2 ppm, 0.06-1.69 ppm and 0.06-0.45 ppm respectively.<br />

Throughout the biological and ecological characteristics of climbing<br />

perch in the nature, most of water quality parameters were acceptable for fish<br />

growth and development in culture systems (P e k a r et al. 1998, X u a n et al. 1994,<br />

K h a n h et al. 1999).

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