Effect of the water height on the gain in weight in tadpoles of Rana catesbeiana Shaw, 1802 (Bullfrog) in intensive cultivation

Abstract

Aiming at the knowledge of the relation between the gain in weight in tadpoles of bullfrog raised in an outdoor experimental plant and the water height in the tanks, a study was carried out at the Experimental Fishfarm in Pindamonhangaba, São Paulo State, Brazil (22°55'55"S and 45°27'22"W), from October 21^st through December 2^nd, 1983. The water column heights were 10, 15, 20 and 25 cm. The population density, 1 tadpode per 1/2 liter of water, remained constant in all tanks. The tanks were in brick and cement and the surfaces measured 1.20 m by 1.20 m. The experimental design was that of 4 treatments and 5 repetitions. The analysis of variance, taking into account the regression, revealed no significant differences between the treatments. It is, thus, advisable, within an economical point of view, that the height of the water column be between 10 and 15 cm, for the conditions referred in this work.