Land use change for shrimp aquaculture ponds and its impact on water use in Marismas Nacionales, Mexico

Shrimp aquaculture is one of the activities that generate impacts on the coastal environment due to its high water use, land modifications, and the discharge of wastewater rich in phosphorus and nitrogen. It is also one of the main drivers of land use change (LUC) in coastal environments. The Ramsar Site Marismas Nacionales (SRMN), considered the most productive wetland in North America, is in northwestern Mexico across the states of Nayarit and Sinaloa. It is one of the main areas in Mexico where intensive shrimp aquaculture is practiced. This study evaluates the growth in surface area dedicated to the construction of shrimp aquaculture ponds using satellite imagery within the municipalities corresponding to SRMN, during the period from 1986 to 2022. The impact on water use and the quality of wastewater discharged directly into the ecosystem was analyzed. The results show that in 1986, the study area had 500 hectares, in 2022 this expanded to 16,465 hectares, with an average growth of 443 hectares per year. Water use increased from 130 hm3 in 1986 to 4281 hm3 in 2022. Regarding wastewater discharge, it was found that in 2022, 57,463 kg of nitrogen and 14,983 kg of phosphorus were released into the system. Data aligns with findings reported at other scales of study and with LUC patterns driven by shrimp aquaculture in others major shrimp-producing countries, which has led to environmental issues such as increased water use and decreased water quality due to the discharge of wastewater enriched with nitrogenous and phosphorous.