Intensive culture of red tilapia based on the natural production. An alternative of fishing production in a tropical coastal lagoon

Abstract

Following up the encouraging levels of production of Red Tilapia in cages, has been proposed the study of this fish in fenced enclosures. The effect of feeding based solely on the natural availability on the growth was evaluated throught two experiments with seed densities of 10 fish/m3  and 20 fish/m3 , respectively, and with a method to both exploit the enormous amount of available natural food: I) use of artificial substrate for perifiton and II) use of underwater lights at night. Up to now the maximum obtained capacity in cages has been of 75 kg/m3 , with seed densities of up to 200 fish/m3 . However, when the seed density was increased, in the little available space, contact among animals was frequent, causing maltreatment and ulcerations which ended in diseases and in an increase in mortality. Mean final weight were 416,26±0,96 g and 405,38±4,22 g in the first experiment and 447,47±4,065 g and 399,43±0,376 g in the second experiment during 9 and 6 months of culture, respectively. Although has not established the maximum carrying capacity, so far has been obtained a production of 1,67 kg/m3 with seed densities of 20 fish/m3  without employing supplementary food. In general the key to  the success of this type of production method was the use at night of underwater lights of cheap design, which allow for continuous feeding by fish, and takes advantage of the nighttime abundance of zooplankton.