SHRIMP FARMS’ INFLUENCE IN A TROPICAL ESTUARY BEFORE DIFFERENT HARVEST CONDITIONS
Shrimp pond. Water quality. Hydrodynamical modeling. SisBaHiA®.
Shrimp farming is often associated with environmental degradation of water bodies because of nutrients and organic matter present on its ponds’ effluent. The discharge adjustment of these effluents in relation to residence time, tidal regime, size and water body’s assimilation capacity are mitigating measures of the adverse effects promoted by shrimp farming. In this context, hydrodynamic and water quality models are useful to support decisions makers about coastal management like discharge of shrimp effluents. However, one of the main difficult of modeling shrimp farm effluent is the data acquisition of the ponds discharge because of the randomness of the crop cycles in each farm. The objective of this work is to verify shrimp farming influence in a tropical estuary, with different harvest scenarios, besides to evaluate a harvest stochastic generation model. The hydrodynamic and water quality simulations were performed using the Sistema Base de Hidrodinâmica Ambiental (SisBaHiA®) and the studying area was the Potengi/Jundiaí estuary, the Brazilian pioneer on the shrimp farming production. A few scenarios were verified: two reference scenarios (without shrimp farm discharges), one scenario with shrimp farm discharge simulated by the random generator of harvest, and two scenarios with harvest concentrated in the neap and spring tides. Results didn’t show representative differences between harvest scenarios. Different discharge management didn’t significantly interfere in the estuary and all harvest scenarios have similar dispersion condition.