de la Lanza-Espino, G.; Silva, R.; Hernández-Pulido, S.; Mariño-Tapia, I., and Enríquez, C., 2017. A retrospective analysis of water quality in an open bay on the Mexican Pacific. In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue, No. 77, pp. 39–50. Coconut Creek (Florida), ISSN 0749-0208.

Lack of knowledge about the complex interactions between the dynamics of natural systems (physical, chemical and biological) and the need for the resources found in coastal environments has led to the unplanned and disorganized development of several anthropogenic activities in the study area. It is important to revert this tendency and promote medium term studies that can help to foresee the unwanted effects, sometimes irreversible, of human activities on the environment. This paper includes results from hydrodynamic and water quality studies carried out in Petacalco Bay, Guerrero (Mexican Pacific) in order to present elements for future appropriate management of industrial outflows in the region. Around this bay there are important rivers and small villages, a major port, chemical and thermoelectric plants, all discharging their (generally untreated) effluents directly into the sea. The results of this study show that the overall water quality is similar to natural concentrations found in the ocean. Nevertheless, eutrophization was found, associated with the fertilizer industry, and the hot water discharge from the thermoelectric plant generates hot plumes, which dissipate in the environment, despite the intense and variable hydrodynamic characteristics of the region.