(a) Changes in the hydrological pattern. Shrimp pond levees change the pattern of runoff and sometimes they interrupt seasonal streams and tidal channels affecting mangroves by altering fresh water availability and the flooding periods. Such events are particularly critical in semiarid regions of the continental margin of the Gulf of California and might induce mortality of vast mangrove zones, particularly those species under environmental stress. Levees of roads to shrimp farms and fishing sites pose a similar hazard to mangroves when they alter tidal channels. Pumping operations for water exchange in shrimp farms can cause significant changes in the hydrodynamic patterns of coastal lagoons. Additionally, an artificial rise of water levels in ponds enhances saline intrusion.