Felipe P.A Cohen1, Elisabete S. Braga2, Vitor G. Chiozzini2 and Estela M. Plastino1
1Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, 05508-090 São Paulo, Brasil
2Instituto Oceanográfico da Universidade de São Paulo, Praça do Oceanográfico 191, 05508-120 São Paulo, Brasil
We set a total of four systems, each on composed by a black-cylindric fish tank (45 L) in recirculation with a white-rectangular alga tank (20 L), filled with synthetic seawater, for 91 days. Alga tanks were stocked with 38 g of female gametophytes (Gracilariopsis tenuifrons) and fish tanks with 80 individuals (Amphiprion percula; ~39.0 mg.ind.-1). Photosynthetically active radiation was ~100 μmol photons.m−2.s−1 (12h light.d-1). Fish were fed twice a day and tanks were siphoned three times a week to remove particulate solids. Partial water change (PWC) was done when tanks showed higher values of measured nutrients. Mean values for salinity, temperature and pH were 35 ± 1, 25.9 ± 0.6 °C, and 8.07 ± 0.23, respectively. Mean value of NH4-N was 0.01 ± 0.00 mg.L-1. NO2-N showed an increase in the first 40 days, reaching 2.0 ± 1.0 mg.L-1, but followed by a fast decrease, reaching a mean of 0.2 ± 0.2 mg.L-1 until the end. NO3-N and PO4-P accumulated, reaching a mean of 16.6 ± 4.4 mg.L-1 and 4.9 ± 1.3 mg.L–1, respectively. Gp. tenuifrons showed a constant growth, reaching a mean mass of 131.3 ± 31.3 g (mean growth rate of 1.4 ± 0.8 %.d-1). Fish reached commercial size (498 ± 49 mg) with 97 ± 2% of survival. We did eight PWC per tank, resulting in a production of ~7 fish per kg of commercial salt. Using Gp. tenuifrons may be an opportunity to reduce effluent and to increase profitability in marine ornamental fish aquaculture. FAPESP 2019/09269-9.