Shrimp aquaculture environmental diagnosis in the semiarid coastal zone in Mexico

Environmental diagnosis of supra-littoral and semi-intensive shrimp farm systems (SCS) in the northwestern part of Mexico had been developed for a 10-years period (1993 to 2003). The activities in the construction, operation and abandonment phases were evaluated by an environmental impact diagnosis analysis, causal diagrams, complex analysis systems, relevant environmental criteria analysis, and fuzzy logic impact assessment. The SCS, divided in Natural and Socioeconomic subsystems, showed important negative impact in the construction phase affecting the flora and fauna because of vegetation removal, but as positively was detected the employment because of the number of people hired. During the operation phase, positive impacts in the Socio-economic subsystem (SEC) were produced by high-educated employments offers, and increase of life quality. Opposite, the most important negative effect was caused by pollutant-enriched water discharges. In the abandonment phase, negative effects were identified by soil salinization, acidification, erosion increase, or the ecologic barriers' role that ponds play. The combination of the methods applied in this work help to identify in an ordinal way the magnitude of the environmental impacts on shrimp cultures in any region and different conditions.