Background. The observed expansion of the red lionfi sh, Pterois volitans (Linnaeus, 1758), in the Caribbean represents one of the most rapid marine fi sh invasions in the history. The invasion rate of this top predator has resulted in a marked negative effect on local fi sh populations in the Caribbean by impacting local biodiversity. The main aim of this work was to conduct the morphological identifi cation of prey items from the lionfi sh diet, and to determine the spatio-temporal variation of the lionfi sh diet composition in different sites of the Mexican Caribbean, to have a better knowledge of how this invasive species is impacting local species of commercial or ecological importance in the region. Materials and methods. The Mexican Caribbean study area was divided in three zones; North (one locality Isla Contoy), Central (three locations Xpu-Ha, Akumal and X'Cacel), and South (two locations Banco Chinchorro and Xcalak). The fi sh were collected, from different habitats, using SCUBA diving and Hawaiian harpoon. Collected fi sh were taxonomically identifi ed, measured for total length (TL) and standard length (SL), and weighed to the nearest gram. Prey items were identifi ed using a dissection microscope. After identifi cation, prey items were separated, counted, and weighted individually. Finally, statistical analyses were made for all the samples using this study database, containing predators and prey items. Results. A total of 76 prey species were identifi ed in 962 lionfi sh stomachs; 47 of them represented fi shes and 29-crustaceans. Fishes of families Pomacentridae, Labridae, and Scaridae were the most abundant diet components of lionfi sh. Rhynchocinetidae, Penaeidae, and Solenoceridae were the most representative Crustaceans families among the prey items. Molluscs were present as diet components only as incidental food. Conclusion. Red lionfi sh, known for its high competitive capacity, preyed more intensively on fi shes than on crustaceans. Therefore, it is evident that the lionfi sh presence in the Mexican Caribbean may affect mainly the local population of reef fi shes. The presently reported results contribute to a better understanding of the red lionfi sh invasion in the Caribbean.

Sunscreens have spread widely into aquatic systems over the last 18 years in Quintana Roo, Mexico. This contamination is caused by intensive use as a result of leisure activities, as sunbathers apply the substances intensively (up to 83.75% of tourists and locals). Moreover, 25% of the compounds are mainly released into the water through topical products washing off. On average, 300,000 tourists arrive every week in Quintana Roo, increasing the contamination. In addition, there are no recent studies on sunscreen toxicity and the hazards this represents for the native zooplankton of Quintana Roo. In order to assess their adverse effects, acute toxicity was assessed for nine sunscreens (five non-biodegradable and four biodegradable) in four zooplankton species (Brachionus cf ibericus, Cypridopsis vidua, Diaphanocypris meridana, and Macrothrix triserialis). In total, 21 LC50 values were obtained, which are the baseline values for estimating risk and for determining the expected maximum permissible concentration. Our data on toxicity to freshwater species compared to marine species indicate that freshwater species are more sensitive than marine species. In conclusion, biodegradable sunscreen posed a moderate risk, and non-biodegradable posed a high risk. Our outcomes suggested that the maximum permissible concentrations for the contamination of sunscreens were 8.00E-05 g/L for non-biodegradable and 1.60E-04 g/L for biodegradable sunscreens.

The present study reports estimates of alpha (), beta () and gamma () diversity for the fish community of Chacmochuch Lagoon (SE Mexico), a natural protected area located in the northern portion of the Mesoamerican Barrier Reef System. Fish specimens were sampled in 2004 and 2006. Field work was carried out at three climatic peaks: at 13 stations using a 70 m-long beach seine. The collected data were supplemented with information obtained from a previous work conducted in 2002 and were then analyzed with multivariate statistical methods. In addition, fish composition results from this study were compared to those reported for other similar ecosystems of the region. A total of 68 fish species were recorded, determined as peripheral (high-salinity species, usually marine affinity) most of them. Most of the fish species collected were determined as rare, and a few number of species were determined as common and dominant. Salinity, TSD, temperature, dissolved oxygen and other variables were measured to determine the influence over the fish communities, four groups of sites where determined. Results indicated a gradual decrease in the degree of species replacement towards the interior of the system (away from the coast). The estimated value of gamma diversity was high compared to that reported for other coastal systems of the region and, due to the high degree of habitat heterogeneity found in this system; beta diversity had a greater contribution to gamma diversity than alpha diversity. This lagoon acts as a nursing area for many of the fish species collected in this study as indicated by the presence of juvenile stages.En el presente estudio, se midió y se determinó la biodiversidad alfa (), beta () y gamma () de la comunidad de peces en el Sistema Lagunar Chacmochuch, un Área Natural Protegida (ANP) localizada en la zona norte del Sistema Arrecifal Mesoamericano. El trabajo de campo se realizó en 13 sitios de muestreo durante los ciclos anuales 2004 y 2006, considerando los tres picos climáticos representativos de la región. Para la captura se utilizo un chinchorro de 70 m de largo. La matriz de información utilizada para el análisis se complemento con datos obtenidos a partir de un trabajo realizado durante el periodo 2002. Análisis multivariados fueron utilizados para la generación de resultados. Los resultados de la composición de peces se compararon con los reportados para otros ecosistemas similares de la región. Un total de 68 especies fueron registradas siendo periféricas (especies de alta salinidad y afinidad marina) la mayoría de ellas. Del registro, la mayoría de las especies se determinaron como especies raras, un número menor fueron especies comunes y dominantes. La salinidad, SDT, temperatura, oxigeno disuelto y otras variables fueron medidas para determinar su efecto sobre la comunidad de peces, encontrando cuatro agrupaciones de sitios. Los resultados indican una disminución gradual de las especies hacia el interior del sistema (al alejarse de la costa). La diversidad gamma es alta comparada a...

The family Acanthuridae is a key component of coral reef ecosystems as it controls macroalgae biomass buildup. During routine monitoring of benthic communities in the Mexican Caribbean, we observed unusual behaviour of a group of Acanthurus chirurgus, which were feeding on a tuna head left on site by travel tour personnel. This phenomenon has been documented in other herbivorous fish species, especially in places where tourism is a major coastal activity. Although many Acanthurus seek additional sources of protein by feeding on detritus, it is unusual for them to feed directly on fish flesh. Acanthurus chirurgus will incorporate proteins from animal tissues whenever the opportunity arises. Such opportunities occurred rarely in the past, but have become more frequent recently, related to increasing tourism activities where flesh is used as bait to attract the surrounding fauna.

The lionfish is the first invasive species that came to the western Atlantic region to establish itself as an ecological and economic threat to coral ecosystems and commercially important consumption species. Fifteen specimens were collected in Quintana Roo, Mexico, to analyze the chemical composition of the lionfish (Pterois volitans) as a strategy to promote its consumption by the population. They were gutted, filleted, homogenized and chemically analyzed. The analyzed LF had an energetic protein content of 103.89 kcal 100 g-1 of the fillet (20.19%) and a fat percentage of 2.56%. The content of P, Ca, Na, K and Mg were 174.15, 26.09, 81.47, 339.73 and 30.27 mg 100 g-1 , respectively. The most abundant essential amino acid was lysine (12.98 g 100 g-1 protein). The present work is important because it reports that the LF could be used as food with the right quantity and quality of protein, and its consumption would diminish its environmental impact.