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).

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.

Inter-habitat variation in density and size composition of reef fishes from the Cuban Northwestern shelf.

Movement and exchange of individuals among habitats is critical for the dynamics and success of reef fish populations. Size segregation among habitats could be taken as evidence for habitat connectivity, and this would be a first step to formulate hypotheses about ontogenetic inter-habitat migrations. The primary goal of our research was to find evidence of inter-habitat differences in size distributions and density of reef fish species that can be classified a priori as habitat-shifters in an extensive (-600km2) Caribbean shelf area in NW Cuba.

[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.

Evidence for protection of targeted reef fish on the largest marine reserve in the Caribbean.

Marine reserves can restore fish abundance and diversity in areas impacted by overfishing, but the effectiveness of reserves in developing countries where resources for enforcement are limited, have seldom been evaluated. Here we assess whether the establishment in 1996 of the largest marine reserve in the Caribbean, Gardens of the Queen in Cuba, has had a positive effect on the abundance of commercially valuable reef fish species in relation to neighboring unprotected areas. We surveyed 25 sites, including two reef habitats (reef crest and reef slope), inside and outside the marine reserve, on five different months, and over a one-and-a-half year period.

Nesting ecology of Chelonia mydas (Testudines: Cheloniidae) on the Guanahacabibes Peninsula, Cuba.

The nesting colony of green sea turtles (Chelonia mydas) at Guanahacabibes Peninsula Biosphere Reserve and National Park is one of the largest in the Cuban archipelago; however, little information about its nesting ecology is available. Temporal and spatial variation in nesting and reproductive success as well as morphometric characteristics of gravid females were used to ecologically characterize this colony. Nine beaches of the Southernmost coast of Guanahacabibes Peninsula were monitored for 14 years (1998-2012) to determine green turtle nesting activity, from May to September (peak nesting season in this area).

[Reproductive biology of Anisotremus interruptus (Perciformes: Haemulidae) in the Mexican Central Pacific].

Anisotremus interruptus is a widely distributed and commercially important species in the Eastern Pacific. A multi-year research on the reproduction of this species was carried out in coastal waters of Jalisco, Mexico. For this purpose, monthly samples were gathered with gillnets of different mesh sizes from 1998-2008.

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 biology of the golden snapper Lutjanus inermis (Perciformes: Lutjanidae) in the central Mexican Pacific].

Reproductive aspects and information on the effect of fishery activities over this species stock are scarce, despite the imperative need of effective protection and resource management programs. To support the possible establishment of closed seasons and catch levels for the area, our study aimed to evaluate the spawning season of the Golden snapper (Lutjanus inermis). For this, fish caught by artisanal fisheries in the Navidad, Tenacatita and Chamela bays (Jalisco, Mexico) were sampled monthly from 1999-2008, and analyzed sex ratios, spawning season and size at first maturity.

Influence of Diadema antillarum populations (Echinodermata: Diadematidae) on algal community structure in Jardines de la Reina, Cuba.

The 1983-1984 mass mortality of Diadema antillarum produced severe damages on Caribbean reefs contributing to substantial changes in community structure that still persist. Despite the importance of Diadema grazing in structuring coral reefs, available information on current abundances and algal-urchin interactions in Cuba is scarce. We analyzed spatial variations in Diadema abundance and its influence on algal community structure in 22 reef sites in Jardines de la Reina, in June/2004 and April/2005.

[Reproduction of the spiny puffer, Diodon holocanthus (Pisces: Diodontidae) in the continental shelf of Mexican Central Pacific].

Diodon holocanthus is an important economic and ecological species of the demersal fish community, caught as bycatch from local shrimp fishery. The reproductive biology of this long-spine porcupinefish has not yet been described, and reproductive season, the sex ratio, length distribution, length at first gonad maturity, and the gonad macro and microscopic features are described. A total of 400 organisms, ranging from 5.

[Analysis of diet composition and overlap in four species of the genus Diplectrum (Perciformes: Serranidae) in the Mexican Central Pacific].

Analysis of diet composition and overlap in four species of the genus Diplectrum (Perciformes: Serranidae) in the Mexican Central Pacific. The information of trophic interactions among species is essential to understand ecosystem function. To assess this in four Diplectrum species, we analyzed the stomach contents of 397 individuals caught using shrimp trawling nets off the coasts of Jalisco and Colima, Mexico.

High spatial variability of coral, sponges and gorgonian assemblages in a well preserved reef.

The main goal of this research was to obtain baseline field data of the composition of sponges, corals, and gorgonian assemblages that can be used as a reference for future analyses of anthropogenic impact. We tested the hypothesis that relatively homogeneous and well preserved reef units can present notable natural variability in the composition of their communities which are unassociated with changes in land proximity or a human impact gradient. Research was carried out in July 2006 at Los Colorados reef, located in the northwestern region of Pinar del Río Province, Cuba at 12 sampling stations.

[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.

Natural and human-induced variability in the composition of fish assemblages in the Northwestern Cuban shelf.

The main goal of the study was to obtain field data to build a baseline of fish assemblage composition that can be used comparatively for future analyses of the impact of human actions in the region. A basic network of 68 sampling stations was defined for the entire region (4,050 km2). Fish assemblage species and size composition was estimated using visual census methods at three different spatial scales: a) entire region, b) inside the main reef area and c) along a human impact coastal gradient.

[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.

[Trophie webs of reef fishes at Cuba's NW area. II. Functional groups].

A conceptual model of the food webs, mainly with fish, was built in a rocky shore of Havana City with data covering from October 2004 to February 2006. The stomach contents of the most abundant fish was complemented with the literature. We used the Relative Importance Index method to describe diets of carnivorous and omnivorous fish; and a modification of the Relative Abundance method for sponge eaters and herbivorous fish.

Recent region-wide declines in Caribbean reef fish abundance.

Profound ecological changes are occurring on coral reefs throughout the tropics, with marked coral cover losses and concomitant algal increases, particularly in the Caribbean region. Historical declines in the abundance of large Caribbean reef fishes likely reflect centuries of overexploitation. However, effects of drastic recent degradation of reef habitats on reef fish assemblages have yet to be established.

Effects-based assessment in a tropical coastal system: status of bicolor damselfish (Stegastes partitus) on the north shore of Cuba.

The research was carried out to determine whether there are individual-level differences in the bicolor damselfish (Stegastes partitus) within the altered fish communities located on the north coast of Havana, Cuba. There was strong evidence of changes in some morphological and physiological characteristics associated with the impact of land-based pollution in the coastal zone. A combination of impaired recruitment due to habitat degradation with increased food supply due to eutrophication seems to be the best explanation for fishes being heavier and longer at polluted sites.

Fish assemblages on fringe coral reefs of the northern coast of Cuba near Havana Harbor.

It is difficult to separate effects on fish community assemblages due to anthropogenic stressors from natural factors. We examined small-bodied-fish communities along the northern coast of Cuba near Havana Harbor during the dry (February/March of 2000) and wet (June 2000) seasons. Over 35,000 individual fish were visually counted at 15 sites along the coast in three areas located 0-2.