Comparison of growth rate of Siamensis Pangasius( Pangasius macronema Bleeker) in cage culture with different stocking rates (Thai)

Abstract

A study on the effects of stocking densities on growth and survival rate of Pangasius macronema
Bleeker cultured in floating cages for 5 months was undertaken. These fishes with average weight and length
of 2.16 g and 6.35 cm were stocked at 60, 80, 100 and 120 individuals/m in 1x1x1.5 m cages (12 cages)
in pond at Nong Khai Campus, Khon Kaen University. They were fed with no less than 30% of protein twice
a day (08.00 am. and 17.00 pm.). Fish sampling for growth and length were monitored every month. The 
results indicated that the mean for weight gain were 16.10± 1.82, 16.08 ± 0.83, 16.13 ± 0.54 and 18.21 ± 0.52 g, respectively and the mean for length gain were 6.79 ± 0.26, 6.90 ± 0.29, 7.15 ± 0.31 and 7.35 ± 0.23 cm, respectively. The average daily weight gain were 0.107 ± 0.012, 0.107 ± 0.006, 0.108 ± 0.004 and 0.121± 0.003 g/day, respectively. The specific growth rates were 2.896 ± 0.097, 2.898 ± 0.045, 2.901 ± 0.029 and 3.009 ± 0.025 %/day and the survival rates were 86.67 ± 10.14, 84.17 ± 10.03, 89.33 ± 7.51 and 92.22 ±3.76 %, respectively. The food conversion ratios were 5.10±0.41, 5.19±0.08, 4.71±0.21 and 4.04±0.16, respectively. The result of statistical analysis indicated that only the food conversion ratios were significantly different (P<0.05). Three different points of cage placement far fromthe shore did not affect the survival rate or the growth of fish.