No abstract

No abstract

No abstract

The density, taxonomic composition, and spatial and temporal distribution of the estuarine ichthyoplankton of Bahía Málaga (Pacific coast of Colombia) are described, as well as the relationship between biological parameters and some physicochemical variables. Samples were collected at 12 stations along the principal navigation canal; these samples were taken in four areas following the design of Barletta-Bergan. Surface sweeps were carried out with a conical-cylindrical net (mesh size 500 µm, mouth diameter 0.6 m, length 3.5 m). Salinity and temperature were measured before each sweep. A total of 69019 larvae/1000 m³, representing 23 families, 36 genera and 40 species were collected during monthly sampling from September, 2009 to February, 2010. Carangidae (39.0%) was the most abundant family, followed by Sciaenidae (27.1%) and Engraulidae (20.1%). The most frequent families were Sciaenidae (26.6%), followed by Carangidae (22.8%) and Engraulidae (14.7%) which are important families in larval fish assemblages in tropical estuaries. Eighty percent of total density was provided by six species, of which Seriola morphotype 1 (Carangidae) and Cetengraulis mysticetus (Engraulidae) were the most abundant and dominant. No correlation was found between density and salinity (Spearman, R = 0.23) or temperature (Spearman, R = 0.51). Analysis of spatial and temporal variations of larval density shows significant differences among the months sampled (Anova, p = 0.0029; p < 0.05), but not among areas (Anova, p = 0.078), suggesting that Bahía Málaga offers adequate conditions for the presence of fish larvae.

No abstract

Understanding and connecting the impact of anthropogenic activities on mangrove food webs is a research challenge. Has research on the subject been able to find answers using stable isotopes? The present opinion paper analyzed the utility of stable isotopes in tracing the impact of anthropogenic activities on mangrove food webs and if the research questions raised could be answered using these chemical markers. Representative research papers (16) focused on the use of stable isotopes (δ 13 C, δ 15 N, δ 34 S, δ 2 H, δD,206Pb/207Pb, and 208Pb/207Pb) to evaluate the effect of anthropogenic activities (Sewage discharge, timber harvesting–deforestation, metallurgical activities, hydrological disruption, aquaculture ponds, and urban development) on mangrove food webs were selected. Each article included at least one group of consumers (invertebrate or fish). Publications only focused on water quality or primary producers were not included. Most studies managed to determine the effect of the anthropogenic activities on the food web’s stable isotope values. Based on the above, we concluded that these markers are an effective tool to determine affectation patterns on the structure and function of mangrove food webs. The results obtained herein facilitate the correct management of mangroves and their derived resources.

Los peces criptobentónicos contribuyen de manera significativa a la dinámica trófica de los ecosistemas costeros. Este estudio tuvo como objetivo determinar la composición de esta comunidad y comprobar si su estructura difiere temporal y espacialmente en el Parque Nacional Natural Uramba Bahía Málaga (Pacífico Oriental Tropical). Los peces se recolectaron utilizando sustratos artificiales en tres zonas, entre junio de 2008 y agosto de 2009. Se registraron 26 especies, pertenecientes a 11 familias. Gobiidae y Labrisomidae fueron las familias más representativas (especies: 34,6 % e individuos: 66 %). La riqueza y abundancia aumentó en un gradiente del interior hacia el exterior del parque. Utilizando estadística multivariada, se identificó un patrón espacial en la estructura de la comunidad, con localidades internas significativamente diferentes de las medias y externas. Cerdale ionthas, Gobiosoma seminudum, Starksia fulva y Gobulus hancocki fueron responsables de esta diferenciación (contribución > 59 %). El uso de sustratos artificiales para tomar muestras de peces criptobentónicos demostró ser una forma eficiente de identificar una parte de la ictiofauna que no había sido identificada mediante técnicas de muestreo tradicionales y también fue útil para comparar la variabilidad espacial de esta comunidad. La comparación con comunidades de peces criptobentónicos en otras regiones biogeográficas indica que, debido a la baja riqueza de especies en el Pacífico Oriental Tropical, estas comunidades tanto en Colombia como en México muestran baja redundancia funcional y considerables diferencias en sus preferencias tróficas.

The Sunbittern (Eurypyga helias), despite having a wide distribution, is poorly studied and with few records in its area of distribution. Updating the distributions of species allows us to understand distributional patterns which are useful in ecology and conservation, especially for rare or threatened species. Given this situation for E. helias and the new records outside its historical range, here we present its updated distribution and a new record in the south of the Middle Magdalena Valley in Colombia. Using occurrences with preserved specimens and photographic records we build an Ecological Niche Model using the algorithm implemented in MaxEnt. The new record was found in the municipality of La Belleza, Santander in northern Colombia. Its range extends approximately 200 km south of its historical distribution. In Venezuela, it could reach the northern part near the foothills of the Cordilleras Central and Oriental. In Bolivia to the south over the Chiquitano Forest. In Central America, it extends to the lowlands near the Cordillera Central and the Cordillera Volcánica Central, and in North America to southern Mexico. The model suggests that tropical lowlands are more suitable for the species than cold temperate zones, also, the Middle Magdalena Valley is a suitable area, however, the species prefers forested and preserved areas. Some distribution patterns could be explained by different biogeographical barriers, but phylogeographical analyzes are needed to test this hypothesis.