Mercury concentrations and stable isotopes (δN and δC) in fish muscle indicate human impacts in tropical coastal lagoons.

Coastal lagoons are essential nursery habitats of many marine fishes, but they are often sites of intense human activities that impact water quality and potentially the fish using these habitats. We compared the variability in nutrient uptake (using δN and δC) and total mercury (THg) levels in juveniles and adults of three common species in two lagoons on the central Mexican coast of the Pacific Ocean during the wet and dry seasons. One of three species, Achirus mazatlanus had higher THg, δN, and δC levels in the lagoon with the greatest wastewater inputs (Barra de Navidad).

Increased mercury and body size and changes in trophic structure of Gambusia puncticulata (Poeciliidae) along the Almendares River, Cuba.

The Almendares River is the largest river draining the area around Havana City, Cuba. The watershed is heavily populated and industrialized, which has had a significant impact on the flow and water quality of the river. The main goal of this study was to analyze the spatial variability in dietary habits, nutrient flow (using stable isotope ratios δ(15)N and δ(13)C), and mercury (Hg) levels along the Almendares River upstream and downstream of point-source discharges using localized fish Gambusia puncticulata.

[Reproductive and morphological indicators of the fish Gambusia puncticulata (Poeciliidae) in very polluted sections of Almendares River, Cuba].

The Almendares River watershed covers a large portion of Havana city. Human activities have negative impacts over it. We studied the alteration of biological processes in fish from polluted sites.