Spatial and Temporal Dynamics of Trophic State Indicators in Lake Yojoa (2022-2025)

Abstract

Eutrophication processes in lakes generate significant impacts on both aquatic biodiversity and the livelihoods of communities that depend on these ecosystems. This study evaluated the water quality of Lake Yojoa, Honduras, by analyzing temporal trends, spatial differences among three sites distributed from north to south, and the vertical structure of the water column. The research combined data from two monitoring periods (November 2022–April 2023 and November 2024–April 2025). Physicochemical variables such as Secchi depth, total phosphorus, total nitrogen, dissolved oxygen, and pH were analyzed to identify temporal and spatial patterns. In addition, the Trophic State Index (TSI) was calculated using Secchi depth, total phosphorus, and total nitrogen. Results showed increased water transparency and higher total nitrogen concentrations during 2024–2025, while total phosphorus remained relatively stable between periods. No significant differences were detected in surface water (epilimnion) among sites, suggesting a homogeneous composition likely driven by wind-induced mixing. In contrast, vertical profiles revealed significant differences in temperature, dissolved oxygen, phosphorus, and salinity, indicating thermal stratification and nutrient accumulation in deeper layers. Overall, the findings provide evidence of slight improvements in some water quality indicators after the reduction of intensive cage aquaculture, while also highlighting the persistent influence of internal and external nutrient loading on the trophic state of Lake Yojoa.