Fishes as indicators of untreated sewage contamination in a Mexican coastal lagoon.

Lagoons are important nursery habitats for fishes but are often sites of intense human activity including wastewater discharges. The goal of this research was to compare stable nitrogen (δN) and carbon (δC) isotopes, total mercury (THg) and other metal levels in four selected fish species among sites with different levels of untreated sewage discharge inside Barra de Navidad coastal lagoon in the Mexican Pacific. Three species from sites heavily impacted by sewage showed higher δN and δC compared to those from non-impacted sites.

[Spatial and temporal mangrove litter production in Barra de Navidad lagoon, Jalisco, México].

Barra de Navidad lagoon is a coastal wetland of international importance (Ramsar site) and it is included among the 81 Mexican mangrove priority sites. One of the most valued characteristics of this lagoon is the presence of mangrove forest in a good conservation state. The goal of our research was the measurement of mangrove litter production and environmental factors influencing its dynamics.

[Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries.

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.

[Abundance variations of fishes from sites with different levels of pollution in the sublittoral sector of Havana City, Cuba].

The impact of human activity affects fish populations. We studied the abundance of three selected fish species (Stegastes partitus, Thalassoma bifasciatum and Halichoeres bivittatus) in four sites with different degrees of pollution in Havana City: 30th street and 16th street; Miramar; Red Boy of Havana Bay; and the ending ofAlmendares's River. The sites were divided into five zones depending on their bottom characteristics.

[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.