Rearing Shrimps in Pens: A Predictive Model for Impact Assessment

A predictive model for impact assessment of shrimp (Farfantepenaeus paulensis) culture in pen enclosures was developed. Experiments were carried out at Saco da Mangueira, a small embayment at the Patos Lagoon estuarine area (southern Brazil). Nitrogen budget was assessed considering inputs and outputs from the culture system. The measured parameters were water flow, shrimp density, pen mesh size and clogging effect, artificial diet quality, and food conversion rates. Shrimp excretion was estimated from literature available. A N-NT concentration of 0.07 mg L⁻¹ of was assumed as a conservative critical reference value to assess environmental impact and water deterioration. Trials showed that for Saco da Mangueira conditions, a total number of 70 pen enclosures of 0.3 ha (i.e., a total production of 32.2 ton) is recommended as a maximal number. This model is a useful tool for impact assessment and coastal management and may be applied to other estuarine areas.