The present work aims to evaluate the efficiency of a biochar biofilter to purify the water of an aquaponic system according to the density of fish. For this, a unit has been set up at the Rural Engineering Department of the University of Dschang to conduct the tests. The biofilter made up of biochar based on corn cobs and pozzolan was set up as well as six columns of hydroponic system each connected to a biofilter and each containing three basil plants. The experimental device consisted of two densities DP6 and DP9 representing respectively the densities of 6 and 9 catfish per tank. Each density representing a treatment was mounted in triplicate. The fry were fed at 5% of their biomass at 2 frequencies (morning and evening). The physico-chemical parameters were measured once a day for the most part. Plant growth characteristics were measured on the 14th and 28th day after transplanting. Those relating to the growth of fish on the 28th and 46th day after loading. The results showed that the physico-chemical parameters of the water remained within the standard range required in aquaponics whatever the density, thus reflecting the positive effect of the biofilter. The DP6 fish recorded a higher weight gain of 15.26 g against 13.87 g for the DP9 after 46 days of rearing. As for the basil plants, those of the DP6 recorded the greatest average height of 30.88 cm. However, no significant difference was recorded between the treatments for either fish or plant growth. Subject to future work aimed at evaluating the functioning of the system over a relatively longer period, the installation of the biofilter makes it possible to increase the stocking density of the fish and, in turn, the yield.

A zooplankton production trial based on chicken manure and guinea pig droppings was conducted between July and August 2014 at the Dschang University Research and Application Farm to contribute to the improvement of the productivity of fish farming systems. This work was aimed at determining the period and the best fertilizer to produce some zooplankton of interest necessary for larval rearing. An experimental design of 2 treatments and one control (unfertilized): T1 (chicken manure), T2 (guinea pig droppings) at a rate of 2.13 kg /are each triplicate was used in a completely Randomized 9 basins of 1 m3 previously inoculated with copepods and rotifers at densities of 14 and 45 ind / l of water respectively. Physico-chemical parameters of water and biological (zooplankton) follow-up was done every 2 days and the collected data were submitted to a one-way analysis of variance. It follows that: Except for temperature, pH and water depth, fertilizers had a significant effect on the physico-chemical characteristics of the water (p < 0.05). The most significantly high zooplankton densities (1161 ± 15 ind / l) (p <0.05) as well as rotifer and copepod species were obtained on day 12 and day 20 in basins fertilized with chicken manure, on the 14th and 22nd day for those fertilized with Guinea pig’s droppings. The highest densities, biomass, daily production and intrinsic growth rates of the copepods were observed in basins fertilized with guinea pig droppings. Each of the fertilizers has been shown to be of interest to produce a specific type of zooplankton, guinea pig droppings for copepods and chicken manure for rotifers.