channel sides avoid erosion. Roads should have culverts to allow tidal flows and terrestrial runoff of water.
To limit eutrophication: (i) shrimp farms should be restricted to non-vegetated seasonal flood plains and not exceed 10% of the adjacent lagoon surface until the hydrological capacity for removing nutrients without eutrophication is known; (ii) In zones with agriculture, discharge channels from shrimp ponds and agricultural lands should be connected into a single channel that carries wastes directly to the open sea, without contact with coastal lagoons, estuaries or bays. The aim of this arrangement is to integrate agriculture and aquaculture activities with ecological and economical functions of coastal ecosystems into a single management plan. Apparently, the most suitable solution to avoid coastal eutrophication is the dilution of waste discharge into the open sea (though not advisable for pesticides and other substances that are not degraded); (iii) Use of adjacent mangroves as biofilters. The capacity of mangroves to remove nutrients has been estimated as 2–3 ha of mangrove needed per one ha of semi-intensive shrimp ponds (Robertson and Phillips, 1995). For certain zones mangrove capacity is overloaded; (iv) Construction of semi natural wetlands inside aquaculture facilities. Aquaculture facilities should include ponds with filtrating organisms (bivalves) and ponds with mangroves or other aquatic macrophytes for water reuse.