The effect of stocking density on growth and survival rate of Bullfrog (Rana catesbeina Shaew,1802)tadpoles(Thai)

Abstract

The effect of stocking density on growth and survival rate of Bullfrog (Rana catesbeina) tadpoles in concrete tank (90 cm diameter and 20 cm of water level) with 80% shading was studied. The one week-old tadpoles with average weight of 0.12 g were stocked at 3 stocking densities of 60, 120 and 240 individuals/tank for 20 days. They were fed to apparent satiation with 40% protein at 10% of body weight twice a day. The result indicated that tadpoles developed two legs at 18 days and four legs at 28 days. The mean weights gained by the experimental tadpoles were 1.45+0.03, 1.24+0.05 and 1.06+0.03g, respectively. The average daily weights gained by experimental tadpoles were 0.073+0.001, 0.062+0.003 and 0.053+0.001 g day-1, respectively. The specific growth rates of experimental tadpoles were 12.86+0.08, 12.12+0.19 and 11.42+0.13 % day-1, respectively. The results indicated that at the end of the experiments, growth of the tadpoles was significantly different among 3 stocking densities (P<0.05), with the survival rates of 31.11+1.92, 21.94+1.27 and 17.78+0.87 %, respectively (P<0.05).