Effects of pollution generated by fish processing and aquaculture activities on the marine ecosystem of Samanco Bay

This study evaluates the cumulative impact of fishing and aquaculture activities on the environmental quality of Samanco Bay (Áncash, Peru) through the integrated analysis of a 17-year monitoring record (2003–2019). Physicochemical, microbiological, and sedimentary variables were examined across eight stations, applying descriptive statistics, spatial differentiation tests, correlation analysis, and Principal Component Analysis (PCA), all conducted under rigorous quality assurance procedures (ISO/IEC 17025). The results revealed well-defined spatial patterns associated with gradients of anthropogenic pressure: reduced water transparency, significant accumulation of organic matter in sediments (14.08%), and recurrent episodes of reducing conditions with elevated hydrogen sulphide concentrations (0.91 mg/L). Dissolved oxygen exhibited high variability and critically low values in areas adjacent to processing plants and aquaculture zones, indicating intensive remineralization and a heightened risk of benthic hypoxia. Coliforms displayed highly skewed distributions, indicating sporadic faecal contamination events associated with intermittent discharges. PCA distinguished two dominant regimes: oxygenated surface waters and deeper waters enriched in nutrients and reduced compounds. Overall, the findings confirm an incipient process of structural environmental degradation in the bay, underscoring the need to strengthen effluent treatment, regulate aquaculture carrying capacity, and adopt adaptive management measures to prevent irreversible ecosystem impacts.