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Reseña sobre el libro Magdalena de Wade Davis, el cual describe aspectos diversos del río Magdalena, desde su nacimiento, hasta su desembocadura.

Brycon moorei is an endemic species of the Magdalena River basin with a strong commercial, sports and consumption fishing pressure; however, knowledge of ontogeny is scarce or non-existent. For this reason, the present study describes and compares early development in this species. Product of semi-natural induced reproduction, at established times, samples were taken from fertilization until day 15 after hatching to characterize the stages of zygote, cleavage, blastula, gastrula, segmentation, organogenesis, hatching and early juvenile. It was found that the latency time was 6 hours after the second dose at 26°C; hatching occurred at 13 hours post-fertilization (HPF). In the larval stage, cannibalism begins at 22 hours post-hatching (HPH); the maximum buccal opening was reached at 37 HPH with 1773.37 µm and the yolk sac was totally absorbed at 37 HPH. For the pre-bending stage, the mean weight was 3.14±0.36 mg and the length were 6.85±0.53 mm; in the final stage of post-flexion, the average weight and total length were 221.6±15.84 mg and 25.66±0.64mm, respectively. Finally, juveniles with the same characteristics as an adult were presented at 326 HPH. It is concluded that Brycon moorei presents an embryonic and larval development, like most of the species of the genus Brycon and others of the Characidae family; but with the shortest time to consume endogenous reserves and with the shortest time to start cannibalism. [ABSTRACT FROM AUTHOR]

Copyright of Historia y Sociedad (01218417) is the property of Universidad Nacional de Colombia, Facultad de Ciencias Humanas y Economicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Este artículo busca sacar a flote y estudiar diferentes historias de la materia presentes en el río Magdalena en Colombia, a través de la novela En el brazo del río (2006) de Marbel Sandoval Ordoñez, y la crónica Los escogidos (2012), de Patricia Nieto. El objetivo de mi lectura es analizar el fenómeno del río, mediante el concepto de ‘viscosidad porosa’, es decir, evidenciando el enmarañamiento entre cuerpos humanos y no humanos que se da en este y cómo estos reconfiguran los discursos alrededor del Magdalena. Usando una metodología que parte desde los presupuestos de los nuevos materialismos y las humanidades azules, propongo una mirada desde una ontología relacional que reconoce la capacidad expresiva (creativa) y el potencial de acción (agenciamiento) del río. A partir de esto realizo una lectura atenta de las dos obras, identificando dónde se visualizan dichos enmarañamientos y cómo la forma de dichas obras literarias permite una reconfiguración del sentido del río. Esto me permite mostrar que las historias de violencia y riqueza que han configurado el Magdalena están, indudablemente, conectadas con la materialidad del mismo, de los cuerpos humanos asesinados que recorren el río en constante interacción con otros animales, o de las aguas del Magdalena entrelazadas con el petróleo que se filtra por el extractivismo de su subsuelo. Por lo tanto, en estos textos literarios el fenómeno del río Magdalena se complejiza y se densifica, permitiéndonos reconocer cómo nuestra realidad esta enmarañada con otros cuerpos humanos y no humanos que habitan nuestro mundo.

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Los estudios sociales de la infraestructura han dado cuenta de la naturaleza no-lineal, múltiple y contradictoria de las temporalidades de estos aparatos técnico-científicos. No obstante, nuestro conocimiento sobre su pluralidad contrasta con la escasa comprensión que tenemos de su capacidad para sincronizar múltiples experiencias temporales en narrativas históricas hegemónicas. Con base en una etnografía de archivo del documental 50 años de historia para una realidad, este artículo analiza los principales dispositivos y operaciones de producción temporal de la represa de Betania en la cuenca alta del río Magdalena. El trabajo contribuye a la literatura sobre las temporalidades no-lineales de la infraestructura, en cuanto pone de presente que la multiplicación de experiencias temporales y la producción de narrativas históricas hegemónicas son operaciones paralelas y coconstitutivas, cuyos efectos políticos deben ser leídos de manera conjunta.

Contexto: El brazo de Mompox (río Magdalena) se ubica en una zona caracterizada por cotas bajas, su dinámica fluvial tiende a desbordar su cauce e inundar zonas aledañas en periodos de fuertes lluvias. El objetivo de esta investigación es determinar la dinámica fluvial del brazo de Mompox, en el corregimiento de Cantera (Bolívar, Colombia), mediante análisis multitemporales de imágenes satelitales. Métodos: Se realizó una revisión bibliográfica de estudios efectuados, así como un análisis del caudal medio, mínimo y máximo en las estaciones hidrometeorológicas del IDEAM (Instituto de Hidrología, Meteorología y Estudios Ambientales), ubicadas en los alrededores del área analizada; posteriormente, se plasmó una geomorfología utilizando imágenes satelitales de los años 1960, 1969 y 1977 (en periodos húmedos), y 2009, 2014 y 2017 (en periodos secos). Resultados: La subcuenca del brazo de Mompox presenta una topografía suavizada plana, las cotas varían un metro entre unas y otras aproximadamente. Cuenta con un sistema fluvial meándrico con drenajes estacionarios trenzados, paralelos al brazo de Mompox; los drenajes y canales están interconectados con depresiones (ciénagas y humedales) que almacenan cuerpos de agua por un tiempo considerable a lo largo del año, estas zonas se conocen como llanuras inundables o llanuras de inundación. Conclusiones: El brazo de Mompox muestra un aumento en su sinuosidad, debido a los procesos erosivos y deposicionales que tiene el río naturalmente, su evolución es estable, se comporta como un río anastomosado, con trazos meándricos en algunos sectores, cumpliendo un papel importante en las inundaciones, proporcionando volúmenes de agua en periodos de lluvias, iniciando así el proceso de inundación.

Copyright of Fronteras de la Historia is the property of Instituto Colombiano de Antropologia e Historia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El presente artículo explora las movilidades esclavizadas en el Nuevo Reino de Granada durante el siglo XVIII, centrándose en el río Magdalena, sus puertos, las zonas rurales aledañas y las redes de caminos que convergían en este. Analiza las múltiples pero muchas veces ignoradas referencias de desplazamientos de mujeres y hombres esclavizados a lo largo y ancho de la geografía fluvial. El artículo demuestra que la población esclavizada, tanto masculina como femenina, forjó prácticas de movilidad, no solo en espacios urbanos sino también rurales. Estas prácticas fueron significadas y legitimadas por parte de los mismos esclavizados, en el marco de la cultura política colonial, y les permitieron defender ciertos grados de autonomía, pero también desempeñar un papel central en la construcción de redes sociales, en la circulación de información relevante para las comunidades y la política local y, en últimas, en la integración de esta geografía fluvial.

We describe the change in the fish community of the Porce River in Magdalena River Basin, Colombia, following the construction of the Porce III hydropower reservoir based on 13 years of monitoring data. The results show a clear reduction of the number of native species, which have been supplanted by colonizing non-native species, especially in the reservoir. Four native species detected prior to dam construction have apparently disappeared, but 12 new species were registered post-construction. We analyzed spatial changes in beta diversity in the aquatic environments surrounding the dam. The new environment generated by the reservoir presents a unique species composition and contributes significantly to the total beta diversity of the system. Altogether three distinct new fish assemblages emerged following reservoir formation and there are now six assemblages where there had previously been three. This dramatic change, already visible within a decade of construction, highlights just how strong of an impact dam construction has on habitats and how rapidly fish communities react in this hotspot for endemic fish diversity. Our findings demonstrate the importance of monitoring fish communities for revealing the impact of damming on river ecosystems and informs potential complementary fish diversity inventories elsewhere in the Magdalena River basin. [ABSTRACT FROM AUTHOR]

Titian Ramsey Peale, was an American naturalist and artist and the youngest son of the painter Charles Willson Peale. He was well-known for his participation as an illustrator in various scientific expeditions in the United States and around the world at the beginning of the nineteenth century and also for his beautiful drawings, product of his research on the Lepidoptera Americana, an order of butterflies. There is little knowledge and very few records of an enigmatic expedition to the Magdalena River in New Granada in which the young Peale participated in 1831. This article wishes to bring to light this expedition through the archival findings at the American Philosophical Society in Philadelphia in order to begin to understand this mysterious journey, the whereabouts of the graphic material and its relevance in documenting the history of foreign nineteenth-century travelers to Colombia. Titian Ramsey Peale era un naturalista y artista americano e hijo menor del pintor Charles Willson Peale. A principios del siglo xix era conocido por su participación como ilustrador en varias expediciones científicas en los Estados Unidos y al rededor del mundo y también por sus hermosos dibujos, producto de su investigación sobre los Lepidoptera Americana, una orden de mariposas. Hay poco conocimiento y muy pocos registros de una enigmática expedición al río Magdalena en Nueva Granada en la que participó el joven Peale en 1831. Este artículo desea sacar a la luz esta expedición a través de los hallazgos de los archivos de la Sociedad Filosófica Americana en Filadelfia para comenzar a comprender este misterioso viaje, el paradero del material gráfico y su relevancia en la documentación de la historia de los viajeros extranjeros del siglo xix a Colombia. Titian Ramsey Peale foi um naturalista e artista norte-americano, o filho mais novo do pintor Charles Willson Peale. Ao começo do século xix, era conhecido pela sua participação como ilustrador de múltiplas expedições científicas nos Estados Unidos e noutros países, e mesmos pelo reconhecimento de suas belas ilustrações, resultadas da sua pesquisa das Lepidoptera Americana, uma espécie de borboleta. Contudo, há poucos registos sobre uma expedição ao rio Magdalena na Nova Granada na que Peale participou em 1831. Este artigo quer trazer à luz a expedição apresentando o pesquisado nos espólios da Sociedade Filosófica Americana em Filadelfia para começa a compreender esta viagem misteriosa, a paragem do material gráfico e a sua relevância na documentação da história dos viageiros estrangeiros na Colômbia do século xix.

A través de muestreos y registros esporádicos obtenidos entre el 1 de junio de 2020 y 30 de abril de 2021, se presenta un listado preliminar de serpientes, para el Municipio de Plato, Magdalena. Se registraron un total de 64 individuos, pertenecientes a 25 especies y 6 familias, siendo Colubridae las más representativa (16 spp.), y Tantilla semicincta y Lygophis lineatus las especies más abundantes. El 36% de las especies presenta afectación por atropellamiento vehicular o muerte por acciones humanas. Finalmente, estos resultados muestran una riqueza importante sobre este grupo faunístico para el municipio, con ésta información se espera promover nuevos estudios, donde se articule la comunidad científica y pobladores en pro de la conservación de serpientes.

Because dams block migratory routes of potamodromous fish to their spawning areas, and energy generation changes natural flow seasonality, it is necessary to identify spawning areas and their conditions. This information will help in management decisions in the Magdalena River basin regarding the future hydropower development. We identified which characteristics of the tributaries to the Magdalena River are important for determining potamodromous fish spawning grounds, and we estimated the percentage of future loss of spawning areas because of dam development. Ichthyoplankton density is directly related to the floodplain area, and inversely related with channel slope. Low channel slopes offer adult fish a longer distance for their upstream migration and a longer time for embryo development during their drift downstream from the spawning areas to nursery habitats (floodplain lakes). These features could increase the migration distance of the adults, the time for initial embryo development, and, because of its relationship with nursery habitats access, the offspring survival. The potential loss of the actual spawning grounds in the river network was estimated to be nearly 70% because of new dams. Our findings will help to reduce conflicts between hydropower and ecological interests. [ABSTRACT FROM AUTHOR]

The Mompox's Branch, is located in close to the county of Cantera, municipality of Margarita (Bolivar), where there have been natural disasters related to floods, affecting human lives, structures and agricultural areas. The objective of the research is to identify and analyze the areas of threat and vulnerability due to flooding in the Mompox's branch (Magdalena River). The methodology consisted of taking information in the field and spatial analysis, through bathymetry, measurements of the water surface and river flow; For the evaluation of threat and vulnerability, a land use map was made by supervised classification of high-resolution satellite images verified with the land cover methodology of the IGAC (Agustín Codazzi Geographical Institute); The hydrodynamic behavior was calculated with the Hec-Ras software, exposing the flooded areas in return periods of 5, 10, 20, 50 and 100 years; showing the areas of vulnerability and threat to which the sector is subjected. Concluding, that the Mompóx branch and its interconnections with nearby bodies of water favor an increase in the water level, due to the fact that the water table rises supersaturating the soil, generating floods; the area with high threat is 792.28 hectares, equivalent to 39.61% of the total area. The percentage of homes with high vulnerability is 76%. Livestock is one of the main economic activities, occupying an approximate area of 101.29 hectares, equivalent to 18.60% of the total study area and has a high vulnerability. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencia Animal - RECIA is the property of Revista Colombiana de Ciencia Animal - RECIA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El desarrollo fluvial es uno de los aspectos que está en boca de todos cuando de apuestas hacia el desarrollo logístico del país se trata. Desaprovechado por años, el transporte fluvial permite alta capacidad de carga, es económico, su impacto ambiental es bajo y tiene gran capacidad de integración multimodal. Es por ello que este artículo presenta una evaluación del desarrollo en infraestructura que ha tenido el corredor logístico del río Magdalena en los últimos 18 años, empezando en el año 2000, recorriendo las propuestas que se han hecho para incentivar y fortalecer el desarrollo de operaciones logísticas efectuadas a lo largo del río. El ejercicio metodológico se provee, en primera instancia, de una descripción sobre la inversión en desarrollo e infraestructura para los puertos del corredor logístico objeto de estudio, entre ellos el de Puerto Salgar en el departamento de Cundinamarca, y la salida del afluente en el puerto de Barranquilla. Posterior a esto, se hace un recorrido de la operación actual en el corredor, y de los corredores que se encuentran en procesos de estudio por parte de entidades gubernamentales para su próxima intervención de acuerdo con las restricciones propias que presenta el afluente. Luego de la exposición en infraestructura se presentará una descripción de los planes de inversión, desarrollo e implementación sobre los planes, para después concluir presentando un planteamiento general de la situación del río, que permita empezar a contemplar elementos sobre el desarrollo del corredor a futuro.

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper analyzes, from a fundamentally philosophical perspective, the political meanings of the literature on the armed conflict, giving as an example the novel En el brazo del río (2006 & 2017) by the Colombian writer Marbel Sandoval Ordoñez. These political meanings can be summed up in three: first, the reconstruction of traumatic memories, which achieve - due to their harshness- a powerful impression on the reader; second, memories converted into vehicles of narratives for the recognition (self-understanding) of how we came to be what we are as a society; and third, the aspiration that a reader affected by this type of narrative can break the vicious circle of violence. [ABSTRACT FROM AUTHOR]

La ictiofauna de la cuenca del río Magdalena, la mejor muestreada de Colombia, todavía presenta información escasa para algunas subcuencas. Tal es el caso de las subcuencas que drenan el nororiente colombiano, donde se están descubriendo nuevas especies y haciendo los primeros inventarios de muchos cuerpos de agua. En este artículo se describen los datos de la principal colección de peces del nororiente colombiano, la Colección Ictiológica de la Universidad Industrial de Santander, en Bucaramanga. Los primeros registros de la colección datan de diciembre de 2002 y a la fecha las colectas continúan activas. La mayoría de los ejemplares han sido recolectados en el sistema de la cuenca del Magdalena y en el departamento de Santander. También incluye ejemplares recolectados en los departamentos de Arauca, Atlántico, Bolívar, La Guajira, Meta, Norte de Santander y Valle del Cauca. La mayoría de los especímenes se fijaron en formol y preservaron en alcohol al 70 %. Actualmente la colección cuenta con 1665 registros, pertenecientes a 9 órdenes, 33 familias, 74 géneros y 100 especies. Los órdenes mejor representados son Characiformes (38,4 % de los registros), Perciformes (31,4 %) y Siluriformes (18,6 %). Entre los especímenes se cuenta con los holotipos de Astyanacinus yariguies y Gephyrocharax torresi y con paratipos de estas dos especies y de Trichomycterus uisae.

Invasive alien species (IAS) are considered the second greatest threat to biodiversity after habitat loss; and therefore, they need to be controlled promptly to avoid irreversible damages to the ecosystems and loss of species. However, this is not an easy task when the IAS is also a charismatic animal. Here, I analyze the case of the invasive hippos in the Magdalena River basin (Colombia) as an example of an IAS charisma. The charisma of this mega-mammal may have affected the Colombian people’s perceptions and attitudes toward its management, and ultimately delayed or prevented control implementation. A transdisciplinary approach considering both biological and non-biological aspects of hippo’s management in Colombia is critical in solving this environmental dilemma.

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Copyright of Lámpsakos is the property of Fundacion Universitaria Luis Amigo, Facultad de Ingenierias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Historical narrations are configured under the particular cover of the gaps between facts and reports of events. Despite these gaps, people participate in history as agents and narrators. This article provides a reflection on the public aspects of academic contributions that analyse the use of the past, memory and history of relationships of the inhabitants of the Magdalena river banks (Rio de la Patria) from an approach of historicity anchored in particular contexts, gaps and times. For some decades, Colombian academy has embraced discussions and interventions that nowadays could be categorized as public history. Interpretations that evidence the polyphony of the memory, the fluctuation of history and the formulation of new enquiries, research lines and forms of political intervention have been jointed and disjointed from those discussions. [ABSTRACT FROM AUTHOR]

Introduction. El Niño phenomenon causes changes in the water quality of surface water sources due to temperature increase and flow reduction. Objective. To analyze the effect of el Niño phenomenon occurring between the second half of 2015 and the first quarter of 2016 on the water quality of the Magdalena River, municipality of Purificación (Tolima). The water analysis is based on the characterization of its turbidity, apparent color, pH, temperature, total hardness, phosphates, nitrates, nitrites, chlorides, iron and mesophilic microorganisms; to determine its behavior before and during said natural event characterized by loss of rainfall and its consequent reduction of river flow, considered the one with the greatest impact ever recorded. Materials and methods. Raw water samples were taken during 2015 and the first quarter of 2016 at the site of the urban aqueduct of the municipality of Purificación - Tolima. Results. Comparatively, during the months of occurrence of El Niño phenomenon in relation to the first half of 2015, water turbidity decreased and the concentration of other indicators increased, especially phosphates, nitrites and iron, which, as dissolved substances, may pass the conventional treatment process and be present in drinking water in concentrations higher than those established by current regulations. An increase in mesophilic microorganisms was also evidenced. Conclusion. During the occurrence of el Niño phenomenon, the Magdalena river presented changes in its water quality with an increase in some contaminants that can pass the treatment process and imply risk to human health. [ABSTRACT FROM AUTHOR]

Variations in rainfall and river level have been identified as the most crucial factors in freshwater fish reproduction in the tropics. Dams and reservoirs change the seasonality of these factors, so fish must develop new tactics to continue reproducing themselves. Our objective was to define the period and sites of reproduction of fish in the middle Porce River drainage, which has been modified by the construction of two reservoirs in cascade (reservoirs Porce II and Porce III). Sampling was carried out from September 2011 to December 2016, during contrasting climatic periods (drought and rains) at 31 sites distributed as follows: in the reservoirs of Porce II and Porce III, in the river channel (above Porce II reservoir, between the reservoirs and below Porce III dam) and tributary streams to two reservoirs. The fish were captured with gillnet, seines and electro-fishing gear. The Vazzoler scale (1996) was used to determine the gonadal development, the gonadosomatic relationship was also estimated and these data were used to make the analysis of the reproductive seasonality of the fish assemblage, which was defined according to the reproductive intensity (RI) and the percentage of mature individuals of the species. The results showed that in the reservoirs the fish reproduce intensely independent of the climatic period, whereas in streams and river a similar tendency is observed, but with an increase of reproduction associated with the dry season. However, the species Brycon henni particularly had a higher percentage of mature individuals during rainy periods in the Porce III reservoirs and in its tributary streams. [ABSTRACT FROM AUTHOR]

In the environmental recovery projects regarding urban rivers, the importance of management models that were used in the past has been minimized with regard to the knowledge of the institutional arrangements that affected the current configuration of the territory. This article uses documentary sources from the 'Historical Archive of Water' to reconstruct the two most important management models that the Magdalena River was subjected to prior to 1974, when it was used as a source of drinking water for the south west of Mexico City. The first model corresponds to the distribution of water that was carried out in the 17th and 18th Centuries, in accordance with the laws prevailing in the area; while the second refers to the functioning of the Water Board promoted by the Mexican State in the first governments emanating from the Mexican Revolution. [ABSTRACT FROM AUTHOR]

Floodplain lakes and associated wetlands in tropical dry climates are controlled by pronounced and severe seasonal hydrologic fluctuations. We examined the plant community response to a bimodal flooding pattern in the Zapatosa Floodplain Lake Complex (ZFLC), Northern Colombia. We measured floristic and quantitative change in four sampling periods emphasizing seasonal differences in plant abundance and life-form structure. Of 79 species identified in the lake complex, 52 were used to characterize eight community types via classification and ordination procedures. Results showed that community structure does not change significantly during the flooding/receding stages. But maximum drawdown phase significantly disrupts the aquatic community structure and the exposed shorelines become colonized by ruderal terrestrial plants. Early rainfalls at the beginning of the wet season are emphasized as an important feature of plant regeneration and community development. The general strategy of the ZFLC vegetation can be framed into the flood pulse concept of river-floodplain systems. Thus, plant communities are mainly responding to disturbances and destruction events imposed by extreme water level fluctuations. Rev. Biol. Trop. 62 (3): 1073-1097. Epub 2014 September 01.

En la cuenca media del río Magdalena (Colombia) se tomaron muestras semanales durante el ciclo hidrológico 2006- 2007 para evaluar la variación espacio-temporal de las larvas de tres especies de peces migratorios (Prochilodus magdalenae Steindachner 1879, Pimelodus spp. y Pseudoplatystoma magdaleniatum Buitrago-Suarez y Burr 2007). Para este análisis se consideró la abundancia y la densidad de individuos en cada una de las muestras tomadas en el canal principal del río Magdalena a la altura de Puerto Berrío (Antioquia). Se capturó un total 490 individuos, de los cuales la mayor abundancia la obtuvo Pimelodus spp. (74,7%), seguido de P. magdaleniatum (13,7%) y P. magdalenae (11,6%). Se encontró que la abundancia y la densidad de las larvas entre los sitios muestreados fueron homogéneas y sólo se encontraron diferencias significativas entre los periodos hidrológicos asociadas a la interacción de factores físicos como el aumento en el nivel de agua.

Vertical measurements of velocity and suspended sediment concentration obtained in two climatic seasons at the mouth of the Magdalena River, Colombia, were used to estimate 1) bed shear velocity, bed shear stress and the bed roughness length by Wall law, 2) the settling velocity, by fitting distributions Rouse and Rouse equation modified and vertical profiles of suspended sediment concentration, 3) bed load sediment transport parameter estimates were determined with the formulations of Meyer-Peter & Müller (1948), Nielsen (1992), and Ribberink (1998). From the estimated parameters, a number of Rouse significantly less than one (0.01 to 0.18), a settling velocity (0.08-3.15 mm s-1) much less than bed shear velocity (15-70 mm s-1), and high values in shear stress (1.1-5.8 Pa) were obtained. It can be said therefore that in the River Magdalena predominates sediment transport in suspension. The values of bottom sediment transport calculated with the three formulations represent lower rates to 5% of total sediment transport. The formulation of Meyer-Peter & Müller (1948) underestimate the transport of bottom sediment due to the conditions under which it was originally calibrated, while Nielsen (1992) and Ribberink (1998) formulations can generate better estimates, because they were originally calibrated with fine sediment, similar to the sediment type reported in the study area. [ABSTRACT FROM AUTHOR]

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The ichthyofauna of the Magdalena River Basin is the best sampled of Colombia and yet, there is scant information about the fish of some of its drainages. That is the case for the drainages of Colombia's North- East, where new species are being found during the first inventories of many freshwater sites. In this paper, we describe the database of the main freshwater fish collection of North-Eastern Colombia, the Ichthyological Collection of the Universidad Industrial de Santander in Bucaramanga. The collection started in December of 2002 and still active. Most of the specimens were collected in the Magdalena river basin system in the department of Santander. There are also specimens collected from the departments of Arauca, Atlántico, Bolívar, La Guajira, Meta, Norte de Santander and Valle del Cauca. Most of the specimens were fixed in formalin and preserved in 70% alcohol. There are currently 1665 records, corresponding to 9 orders, 33 families, 74 genera and 100 species. The most frequent orders were Characiformes (38.4% of the records), Perciformes (31.4%), and Siluriformes (18.6%). Among the specimens in collection are the holotype and paratypes of Astyanacinus yariguies and Gephyrocharax torresi and paratypes of Trichomycterus uisae. [ABSTRACT FROM AUTHOR]