Polyculture of bullfrog tadpoles and Nile tilapia fry.

Two experiments were carried out to test better stocking proportion according to animal size for tilapia (Oreochromis niloticus) and tadpole (Lithobates catesbeianus). The experiments were laid out in a completely randomized design with five treatments (in Experiment I) and four treatments (in Experiment II). In Experiment I, the treatments consisted of a tilapia monoculture; a 75% tilapia + 25% tadpole polyculture; a 50% tilapia + 50% tadpole; a 25% tilapia + 75% tadpole; and a tadpole monoculture. In Experiment II, the treatments were represented by a tilapia monoculture; a 12.5% tilapia + 87.5% tadpole polyculture; a 25% tilapia + 75% tadpole; and a tadpole monoculture. In the first trial, mortality rate differed significantly, with the polyculture treatments having almost 100% mortality of tadpoles. In the second experiment, after adjustments in the initial size of the species, there were significant differences between treatments, with the 12.5% tilapia + 87.5% tadpole polyculture and the tadpole monoculture providing the best results. Regardless of the chosen density, for a polyculture of Nile tilapia and bullfrog tadpoles, ideal conditions would be stocking tilapia fry weighing 50% of the weight initial tadpoles and the proportion of one tilapia for seven tadpoles.