On Monday, November 3, 2025, thousands of dead fish were found at the Dique Cuesta del Viento reservoir in Iglesia-San Juan-Argentina. On Thursday, November 6, the Secretariat of Environment and Sustainable Development informed the community that 'preliminary evidence indicates that the event would be associated with natural conditions of the water body, specifically low dissolved oxygen levels (hypoxia) in coastal areas with little circulation and accumulation of organic matter.' However, on Friday, November 7, the Jáchal No Se Tocha Assembly conducted an analysis with specialists to check the dissolved oxygen levels in the water in different sectors of the Dique Cuesta del Viento. The results show that there are no problems with oxygen levels, as the measurements range from 7.84 mg/L to 9.16 mg/L. This means that the statement by the San Juan province's Environment Secretariat was a lie. Therefore, the Jáchal No Se Toca Assembly demands that Mr. Governor Marcelo Orrego provide the provincial government with technically sound and reliable evidence of what happened (results of heavy metals and other compounds from mining activity in the water of the Potrerillos, Las Taguas, La Palca, Blanco, and Jáchal rivers, which supply water to the Dique Cuesta del Viento reservoir, as well as analysis of heavy metals in the mud and fish of the aforementioned reservoir), and that Mayor Matías Espejo urgently convenes the UNCuyo to carry out water analysis according to the 'Safe Water Ordinance,' as these analyses have not been done for two years. On November 11, the Jáchal No Se Toca Assembly appeared before the Northern Fiscal Unit (Jáchal) to file a criminal complaint and was pleased to learn that on Wednesday, the 5th, the prosecutor had already initiated a criminal investigation for the crime of water poisoning in the Dique Cuesta del Viento. Case file No. MPF-JA-00734-2025. It should be clarified that pejerrey can live without any problems with 6 milligrams of dissolved oxygen per liter of water.
