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Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia 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.)

En este artículo nos proponemos una revisión de trabajo citado el que consideramos entre unos de los más importantes de la extendida producción realizada por el Dr. Emiliano Mac Donagh. Esta obra al momento de su publicación ha trascendido el ámbito de la Ictiología, ya que el autor ha logrado realizar un singular aporte contextualizando el estudio de la fauna y su ambiente, por medio de análisis poco habituales para la época. Este camino no ha sido un hecho aislado para Mac Donagh, sino el germen de una línea de investigación que tanto camino logrará recorrer dentro de nuestra Institución, y en el ámbito nacional.

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones 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 Revista Academica Ciencia Animal is the property of Revista Academica Ciencia Animal 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.)

Comunitat de macroparàsits de la barracuda del Pacífic Sphyraena ensis Jordan and Gilbert, 1882 (Perciformes, Sphyraenidae) de la costa nord del Perú L’objectiu d’aquest estudi és informar sobre la comunitat de macroparàsits de la barracuda del Pacífic Sphyraena ensis Jordan and Gilbert, 1882 (Perciformes, Sphyraenidae) de la costa nord del Perú. De setembre a octubre de 2019 vam adquirir 138 exemplars de S. ensis a Caleta de Zorritos, província Contraalmirante Villar, Tumbes, a la costa nord del Perú. La comunitat de paràsits trobada va estar constituïda per nou espècies de monogenis, copèpodes, trematodes i nematodes. La longitud corporal total dels peixos es va correlacionar negativament amb la intensitat mitjana d’infestació per Pseudochauhanea sp. D’altra banda, l’abundància mitjana de Pseudochauhanea sp. va mostrar una marcada diferència significativa entre les poblacions de peixos mascles i femelles i estava més associada als mascles. Proporcionem una llista de macroparàsits registrats en peixos del gènere Sphyraena presents a l’oceà Pacífic Oriental. Llista de dades publicades a GBIF (Doi: 10.15470/5htffh)

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones 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 Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones 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.)

Introduction: The genus Profundulus is considered a Mesoamerican endemic fish which spreading occurs, from the center-south of the state of Guerrero, Mexico, to the central part of Honduras. They mainly inhabit the upper basins and headwaters of the rivers of the Pacific slope, with less diversity in the Atlantic. Objective: This paper, based on morphological comparison we propose a new species, Profundulus chimalapensis sp. nov., confined to Mexico. Methods: Specimens were collected in the tributaries of the upper basin of the Coatzacoalcos River and were deposited in scientific collections. Morphological data (counts, measurements and skeletal features) were taken and compared with related species. Results: The new species differs from its congeners by having the following combination of characters: 12-15 dorsal-fin rays, 14-17 anal- and 13-16 pectoral-fin rays; dark colored stripe on the flanks; anal fin with a clear distal margin; anterior and posterior margin of the alveolar process of the premaxilla concave; pair of short and wide epiotic processes; and large anal fin base, equal to or greater than length of caudal peduncle. Conclusion: The description of this new Profundulus species from Atlantic side of the Isthmus of Tehuantepec suggests that this area has been a center of speciation for the genus. [ABSTRACT FROM AUTHOR]

In the present work, we conducted an extensive long-lasting inventory of the fishes, using different collection methodologies, covering almost the entire Pindaré River drainage, one of the principal tributaries of the Mearim River basin, an area included in the Amazônia Legal region, northeastern Brazil. We reported 101 species, just three of them being non-native, demonstrating that the composition of this studied fish community is majority composed of native species. We found a predominance of species of the orders Characiformes and Siluriformes, corroborating the pattern usually found for the Neotropical fish fauna. Similar to other studies, this inventory was mainly dominated by small characids, representing 21% of the species herein recorded. When comparing the present survey with other species lists published for this region (including the States of Maranhão and Piaui), we can conclude that the freshwater fish fauna of the State of Maranhão is probably still underestimated. We reported 41 more species, and one more species than Soares (2005, 2013) and Abreu et al. (2019) recorded for the entire Mearim River basin, respectively. We believe, however, that the number of species presented by Abreu et al. (2019) is overestimated. We compared our results with all other freshwater fish species inventories performed for the hydrological units Maranhão and Parnaíba sensu Hubbert & Renno (2006). With these comparisons, we concluded that our results evidenced that a high effort was put in the inventory here presented. The two works including more species recorded from coastal river basins of the hydrological units Maranhão and Parnaíba were the works published by Ramos et al. (2014) for the Parnaíba River basin, one of the main and larger river basin of Brazil, and the compiled data published by Castro & Dourado (2011) for the Mearim, Pindaré, Pericumã, and upper Turiaçu River drainages, including 146 and 109 species, respectively. Our survey recorded only 45 less species than Ramos et al. (2014), and eight less species than Castro & Dourado (2011). However, it is essential to emphasize that the number of species presented by Castro & Dourado (2011) is probably overestimated since they did not update and check the taxonomic status of the species of their compiled data. In several cases, they considered more than one name for the same species. [ABSTRACT FROM AUTHOR]

Copyright of Montes is the property of Colegio y Asociación de Ingenieros de Montes 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.)

Thorichthys panchovillai, new species, is described, from distinctive of the tributaries of the River Coatzacoalcos basin, Mexico. The new species is diagnosed by a set of characters: dorsal fin rays XVI, 8 – 9; anal fin rays VII, 6 – 7; pectoral fin rays, I, 11 – 12; total gill-rakers on the first branchial cleft 11 – 12; subopercular stain present although weakly intensified, it exposes a notable sexual dimorphism that distinguishes it from others: the female possess a black blotch between the fifth and sixth dorsal spine.

We present here an embracing freshwater fish inventory of the Parque Nacional dos Lençóis Maranhenses and adjacent areas, reporting 49 fish species, 33 of which were identified accurately at the species level, representing ten orders and 25 fish families that range from obligate freshwater to estuarine organisms. This number of species is much larger than two previous studies for the park, each reporting just 12 and 33 fishes occurring on freshwater environments. Among the 49 freshwater species recorded in this study, 14 are new records for the Parque Nacional dos Lençóis Maranhenses, and just one corresponds to an introduced species. Some of the 14 new records in the Parque Nacional dos Lençóis Maranhenses, cited above, as well as some of the 16 species which we are not able to identify accurately at the species level, could include undescribed species, but more study is necessary before sorting out which species are truly undescribed, and which are already described ones. The orders reported by this survey which comprise the highest percentage of species richness, excluding introduced species, were: Characiformes, Cichliformes and Siluriformes, in the same ranking position, and Gymnotiformes, as expected for Neotropical freshwater surveys. The families with the highest number of species, excluding non-native species, were: Characidae, followed by Cichlidae, and Loricariidae. Out of the 33 species herein identified accurately at the species level, five of them are species typically found in brackish water environments, and when occurring on freshwater environments, are restricted mainly to estuaries, or, occasionally, the lower portions of the rivers. Thus, we will not address them in our biogeographical comments. From the remaining 28 species, eight did not occur in the Amazon River basin, six of them being endemic to the Maranhão-Piauí ecoregion. The remaining species herein reported also have their distribution recorded for the Amazon River basin, which shows the great influence of the Amazon basin. In the last two decades efforts to inventory the freshwater fish fauna and to taxonomically solve some groups occurring on the Maranhão state have been made. However the knowledge regarding the composition of the Maranhão freshwater fishes is still insufficient and underestimated, with several groups still lacking adequate taxonomic and systematic resolution, and with many gaps of knowledge, something that is not appropriate for our current picture of "biodiversity crisis". As well as, the other Brazilian protected areas, the PNLM fails to preserve its freshwater environment properly, since it includes only fragments of the major river systems of the area, not including and conserving the hole river drainages, mainly excluding their headwaters. Thus, its water bodies are exposed to typical human impacts. [ABSTRACT FROM AUTHOR]

ABSTRACT The history of knowledge about Amazonian biogeography is as rich as its fish community, and a fascinating theme of study in itself. Several current paradigms and controversies about Amazonian fish biogeography are rooted in principles dating from the second half of the 18th to the first half of the 19th centuries. The present work establishes a relationship between current biogeographical ideas and their old predecessors, on the basis of a chronologically-oriented historical continuity analysis. The advent of evolutionary theory has not contributed significantly to a transformation of the knowledge on the biogeography of Amazonian fishes. On the other hand, the two main schools of biogeographical thought (dispersalist and vicariant) had major implications on how Amazonian fish distribution is interpreted. The process was gradual and many hypotheses have combined elements from each of the two schools. Chronologically, practically the entire tradition of Amazonian biogeography takes place within the evolutionary paradigm, although its founder Louis Agassiz was himself an anti-evolutionist. The birth of Amazonian biogeography is Agassiz´s travel in Amazon. That document makes it clear that the author did not consider dispersal as a valid explanation for the biogeographical patterns he found. Later, Carl Eigenmann helps to spread the dispersalist tradition as a model for biogeographical explanations in fish distributions, a phase which lasted until the late 20th century. A major shift occurs with the contributions of Marylin Weitzman, Stanley Weitzman and Richard Vari, who associated the temporal framework of phylogenetic hypotheses with distribution patterns, underscoring the predictive power of vicariant biogeography. The present-day paradigm begins with the work of John Lundberg and attempts to incorporate geomorphological and phylogenetic information into integrative biogeographical hypotheses. Some emblematic problems have delayed proposition of general hypotheses on the phylogenetic biogeography of South American fishes, such as the poor state of knowledge of their species-level systematics; an incomplete distributional record for most species and sparse or non-existent data on the phylogenetic history of most supraspecific taxa. Such drawbacks are now being corrected at a fast pace. Recent advances on geographical distribution and an increasing number of phylogenetic hypotheses will allow unprecedented large-scale biogeographic analyses, including those based on event models and Bayesian inference. Thus, the biogeography of South American fishes, especially Amazonian ones, should soon experiment a new age of progress. The success of that new phase will depend on its ability to recognize and segregate multiple overlapping temporal layers of hydrological changes, and to develop analytical tools that can deal with temporal mixing.

The Ribeirão Frutal basin is located within the upper Rio Paraná system, in the Frutal municipality, Minas Gerais State, Southeastern Brazil. Until now, there was no complete ichthyological survey published for this small basin. Therefore, here we provided a list of fish species from the Ribeirão Frutal and some of its tributaries. We found 31 species of fishes representing five orders and ten families. We identify a likely undescribed and five non-native species in the Frutal basin. Lastly, we recommend new surveys of fishes in small hydrographic basins within upper Rio Paraná system. [ABSTRACT FROM AUTHOR]

Copyright of Neotropical Ichthyology is the property of Neotropical Ichthyology 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.)

La laguna Hule es un cráter de origen volcánico que se ha inundado con el tiempo, dando como resultado una gran masa de agua, sin estudios previos sobre su comunidad de peces. Muestreamos durante cinco meses la laguna y una quebrada (Pata de Gallo) con redes, gancho y línea. Los especímenes capturados se identificaron in situ al nivel taxonómico posible más bajo. La laguna tenía especies que normalmente se encuentran cerca de la vegetación acuática: Amatitlania siquia, Amphilophus alfari, Astyanax aeneus, Cynodonichthys sp., Parachromis dovii, Phallichthys amates y Poecilia gillii (dominante: A. aeneus, P. gillii y P. amates). La quebrada estaba dominada por Brachyrhaphis olomina pero también tenía Rhamdia laticauda. Los índices de baja diversidad (1,48 en la laguna y 0,26 en la quebrada) son característicos de los ecosistemas lacustres. Las hembras fueron, como se esperaba, más grandes y abundantes en P. amates y B. olomina; mientras que en P. gilli, algunos machos eran más grandes. El área se ve afectada por la contaminación, la introducción de especies invasoras, la pesca incontrolada y el uso de equipo destructivo de pesca. Proponemos la demarcación del estado de protección del sitio y la organización de un grupo comunitario para proteger a esta comunidad de peces.

Objetivo. Se analizó la ecología trófica y reproductiva de Bryconamericus caucanus en la quebrada la Venada, Rio Quindío, Alto Cauca, Colombia. Materiales y métodos. Los ejemplares se recolectaron entre enero y diciembre del 2013. Se realizaron análisis multivariados para comparar las características tróficas entre épocas climáticas (bajas y altas lluvias), sexos y estados de madurez (juveniles y adultos). Se analizó también el factor de condición (K), porcentajes numéricos (%N), volumétricos (%V) y frecuencia de ocurrencia (%Fo) para cada presa. La proporción de sexos se evaluó usando pruebas de Chi-Cuadrado y se estimaron los indices gonadosomático (IGS) y de fecundidad absoluta (Fa). Resultados. Se analizó un total de 162 ejemplares (LS: 40-75 mm). Se encontró que B. caucanus es un pez insectívoro (86.47% IRI), con un consumo preponderante de ephemeropteros (Baetidae; 27.71%), hymenopteros (Formicidae; 23.57%), dipteros (Simuliidae 17.36%; Chironomidae 9.79%) y trichopteros (Hydropsychidae; 8.04). Los analisis multivariados revelaron diferencias tróficas entre épocas climáticas, con menor riqueza durante la época de sequía. Entre sexos, las hembras registran una mayor amplitud del nicho trófico. Los adultos, presentan una amplitud de nicho mayor a juveniles. La especie tiene dos eventos reproductivos en los periodos de altas lluvias relacionados con el incremento en la riqueza trófica durante las mismas épocas (i.e. marzo-abril, septiembre-noviembre). Conclusiones. B. caucanus presenta una segregación trófica incipiente entre estadios ontogénicos y sexos. La distinción trófica es sin embargo notable entre periodos climáticos. Los periodos de desove para B. caucanus ocurren a inicio de los periodos de lluvias (i.e. mayo-junio y septiembre-octubre).

Este trabajo examina la relación entre el desarrollo de la pesca comercial marítima y el estudio de la fauna marina en la Argentina de fines del siglo XIX y las primeras décadas del siglo XX. Se analizan las investigaciones ictiológicas, la comercialización de productos marítimos frescos y las oportunidades que ofrecieron los mercados urbanos para la formación de colecciones. También se focaliza en los inicios de la pesca de altura que posibilitaría la captura y estudio de nuevas especies así como la acumulación de información sobre el ambiente marino.

Roeboides xenodon (dentudo) e Orthospinus franciscensis (piaba-facão) são peixes teleósteos de pequeno porte com hábitos alimentares onívoros. Com o objetivo de estudar a morfologia do tubo digestório exemplares de O. franciscensis (n=25) e de R. xenodon (n=16) foram coletados na bacia do rio São Francisco, represa de Três Marias – MG, e fixados em formol a 4%. Em ambas as espécies, o esôfago curto teve início na região cefálica e, após o septo transverso, continuou na cavidade peritoneal até à primeira região do estômago. Em R. xenodon, o esôfago apresentou pregas primárias espessas, estreitas e dispostas longitudinalmente, separadas por sulcos profundos e bordas livres e retas e pregas secundárias entre estas. Em O. franciscensis, o esôfago apresentou pregas primárias espessas e largas, longitudinais, sem sulcos profundos, mas com bordas livres e poucas anastomoses. O estômago é do tipo cecal, em “Y”. Os intestinos apresentaram duas porções: a anterior, mais longa e circunvoluta e a posterior, curta e linear. O início do intestino posterior foi demarcado pela alteração abrupta do padrão da mucosa. O esfíncter anal delimitou posteriormente o tubo digestório. O tubo digestório de ambas as espécies é completo e as adaptações tróficas encontradas no aparelho digestório são condizentes com o hábito alimentar carnívoro.

This paper presents a checklist of the reef fish fauna of the Anchieta Island State Park, a no-take zone in which no extractive activities are allowed, in Ubatuba, Southeastern Brazil. Data was obtained between 2011 and 2013, mainly through underwater observations with snorkelling and SCUBA, and secondarily using scientific fishing (trawling). Published and unpublished data were also verified and compiled. A total of 103 reef fish species, distributed in 78 genus and 50 families was recorded. Haemulidae was the richest family (n=7 species), followed by Epinephelidae (n=6), Pomacentridae, Carangidae and Tetraodontidae (n= 4 each). Haemulon was also the most speciose genera (n=5), followed by Stegastes, Acanthurus and Mycteroperca (n=3 each). Sixty-nine species (67%) are included in global and regional Red Lists. Twenty-five species (24.2%) are within the categories Critically Endangered (CR), Endangered (EN), Vulnerable (VU) and Near-Threathened (NT). The network of Marine Protected Areas in Southeastern Brazil is still incipient, and the considerable number of threatened species in the Anchieta Island State Park clearly indicates the importance of the study area for the conservation of coastal and reef fishes. [ABSTRACT FROM AUTHOR]

Copyright of Instituto Oceanografico de Venezuela (Boletin) is the property of Universidad de Oriente 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.)

Aunque en el título de esta nota se apunta sólo a un verso concreto del Libro de Buen Amor, en realidad se revisan varios pasajes de la obra con referencias ictiológicas y ornitológicas oscuras a las que editores y exegetas no han sabido dar una solución satisfactoria.

Con el objeto de hacer extensivos los conocimientos ictiológicos e incrementar las posibilidades de desarrollo de esta disciplina en nuestro país, se propone la creación de un Programa Educativo a Distancia para la enseñanza de la Ictiología, considerando el desarrollo de temas básicos y especializados, al alcance de enseñanza básica y media, con la finalidad de motivar en estos estudiantes las inquietudes hacia el conocimiento de la fauna íctica tanto la representada en los ambientes marinos como dulceacuícolas del país. El diagnóstico sobre el conocimiento de este tipo de fauna en el ciudadano común es bastante precario. Chile es un país con grandes recursos hidrológicos, una extensa costa, numerosas cuencas, más de 1.000 especies de peces marinos descritas y una fauna íctica dulceacuícola empobrecida. Sin embargo, la población en general, incluso profesionales desconocen la temática, lo que incide en las decisiones de altos niveles administrativos. Esta es una formación que debe comenzar desde la enseñanza básica. Es necesario hacer un esfuerzo para incentivar proposiciones en las que estén presentes estas temáticas. El tema presentado en el VII Simposio-Taller de Ictiología, a modo de pregunta al escolar: "¿Conoces los peces de Aguas Continentales de Chile?", conformada en una clase desarrollada para estudiantes de 7° y 8° años, podría plantearse como extensión y a modo de ejemplo, en la educación extraescolar o en talleres de ciencias. Propongo a la Asociación de Ictiología de Chile liderar un Programa Nacional de Enseñanza de estos tópicos en el paísA proposal is made to develop basic and specialized topics in ichthyology for a Distance Learning Program for elementary and high school students in Chile. The extension of ichthyological knowledge towards high school education will help to increase the development possibilities of this discipline in Chile. Hopefully this Program may be able to stimulate the Ministry of Education to promote interest towards Chilean marine and freshwater ichthyofauna in such students. The diagnosis about the knowledge that the common citizen has of this type of fauna is quite insufficient. Although Chile is a country with great hydrological resources, an extensive coast, more than 1000 described marine fish species, many hydrological watersheds, and, unfortunately, an impoverished freshwater fish fauna, the population, as a whole, and even professionals, are unaware of this issue, which impinges on high level decisions. This is a formation that should start from elementary education. An attempt to promote proposals involving the ichthyological topics is necessary. The topic "¿Know Continental Freshwater Fishes of Chile?", developed for 7th and 8th grade students, is presented as an extension activity towards extracurricular education or workshops in sciences. I propose that the Chilean Ichthyological Association should lead a National Program of Ichthyology teaching for improving this education topic in the country

Few genetic conservation studies carried out in Colombia have applied molecular biology techniques. Protocols and modifications arising from the genetic study of four fish species from the Sinú river basin are presented as guidelines for future work in this field (and with other species) as laboratory standardisation processes are complex. The original commercial kit's DNA extraction protocols were modified as were those for PCR reactions for obtaining micro-satellite markers and AFLPs, as well as allele genotypification. Particular variations were made f or each of the species studied. Key words: DNA extraction; molecular biology; genotypification; ichthyology.

Este trabalho tem por objetivo descrever os potenciais do conhecimento empírico ou prático relacionados à ictiofauna e, de um modo mais amplo, à percepção ambiental da população ribeirinha do rio Piraí, Município de Joinville, Santa Catarina, Brasil. Partindo de uma pesquisa prévia, que teve como resultado um inventário ictiológico preliminar desse rio, foram elaborados os procedimentos metodológicos relativos à dimensão qualitativa do estudo. Com base nos depoimentos dessa população ribeirinha, obtidos mediante entrevista semi-estruturada, organizaram-se as categorias de análise com vistas a uma proposta de tipologia etnográfica. Essa tipologia foi utilizada na análise dos depoimentos dos sujeitos da pesquisa, concluindo-se que o estudo ictiológico desenvolvido sob uma perspectiva de diálogo com o saber popular dos ribeirinhos pode ser muito profícuo, em face do senso de conservação ambiental atrelado à sustentabilidade de seu modo de vida

En Colombia se han realizado pocos estudios de conservación genética aplicando técnicas de biología molecular. Debido a la compleji­dad del proceso de estandarización de las técnicas de laboratorio se presentan los protocolos y las modificaciones realizadas durante el estudio genético de cuatro especies ícticas del río Sinú, con el fin de que sean útiles como guía para futuros estudios, no sólo para peces sino para otras especies. Se realizaron modificaciones de los protocolos originales en la extracción de ADN, la cual fue llevada a cabo con un kit comercial, en las reacciones de PCR para la obtención de marcadores microsatélites y AFLP, así como en la genotipif icación de alelos. Las variaciones realizadas fueron distintas para cada una de las especies trabajadas. Palabras clave: extracción ADN; biología molecular; genotipificación; ictiología; DNA extraction; molecular biology; genotypification; ichthyology.

RESUMENEste trabajo es el resultado de tres muestreos de peces, realizados en una pequeña quebra-da que desemboca en una laguna amazónica, en las cercanías de Leticia en la amazoníacolombiana. Los muestreos se realizaron en los meses de abril, julio y noviembre, abarcandolas estaciones lluviosa y seca. 5.312 peces fueron colectados pertenecientes a 8 órdenes,33 familias, 107 géneros y 148 familias de las cuales 26 son nuevos registros para Colombia.La comunidad de peces presente se caracteriza por tener pequeña talla y bajas densidades.Los contenidos estomacales y los aspectos reproductivos fueron analizados. La comunidadíctica de esta quebrada es independiente de las condiciones presentes en el río Amazonas y susplanos de inundación.

In order to evaluate the effect of the the Clarin channel reopening on the fish community around the lagoons of the External Delta of the Magdalena river, fish samples were collected each month in 15 stations. This channel was opened with the purpose to recover the hydric equilibrium in the region and the mangrove forest and fauna. The fish samples were used to analyse the variations of their community structure between three subregions: Cienaga Grande of Santa Marta, Pajarales and Salamanca Occidental and, between the years (1995 and 1996) before and after the Clarin channel opening. A total of 4161 fishes of S9 especies were captured, and the salinity was found the most is (classification and significance test) showed that the differences of the community structure between zones were greater than between the two years compared. This reflect the higher degree of regional influence from the Magdalena river, than from the local Clarln channel. The year of study was characterized by lower values of salinity than years before in the area. This account from the abundance of the freshwater species found.

The Amazon River floodplains are highly productive pulsing systems from an ecological point,due mostly to the periodic inflow of sediments that are dragged from the Andes by the rivers.In Colombia, this Amazon systems have not been intensely studied, therefore, this study tookplace in an floodplain lake of the Amazon river near the city of Leticia. Ichthyological sampleswere taken at four different times during a year according to the Amazon water level, ascendantwaters (April), high waters (June), descendant waters (July) and low waters (November), inorder to study the variation of fish over time and to create a reference collection of theYahurcaca lake. 134 species were found 54 of which are new reports for the Colombian Amazonregion. The fish community changes its composition and relative abundance throughoutthe periods studied, due to changes in resources related with the hydric pulse. The changes inthe diet during the different periods was analyzed for five predominant species: Triportheus albus,Triportheus angulatus, Triportheus elongatus(Characidae), Rhytiodus microlepisy Schizodon fasciatus(Anostomidae). The Triportheusspecies have a generalized feeding strategy and prefer terrestrialinsects, fish pieces, fruits and seeds. The two anostomids are clearly specialists and feed mostlyof vegetal material from autochthonous or alochthonous origin. In all the species the type andamount of food was different in each period, due to the variation in the resources offer whichrelates with the hydric pulse. The examination of the gonads of the species, suggests that all ofthem have one posture per year, because no mature females were found in any of the periodsanalyzed. Possibly the spawning occurs in the first months of the year, time when the water level begins to rise and floods the lake. The species would present high fecundity because even inimmature stages a high number of eggs was observed. The type and amount of feedingresources, the reproductive strategy and the time of spawning of the fishes are closely relatedwith the fluctuations of Yahuarcaca’s waterlevel, ultimately with the hydric pulse.

El estudio de los peces fluviales argentinos ha sido realizado en el pasado como parte del estudio de los de agua dulce, y ello traía como consecuencia que las observaciones sobre el hábitat fuesen poco señaladas. Por otra parte, salvo los estudios de Berg, que son más orgánicos, la generalidad de los otros fueron realizados sobre colecciones hechas durante expediciones extranjeras o por coleccionistas ocasionales, y generalmente no estaban bien especificadas las localidades, en parte también por culpa de la ignorancia de los autores respecto de nuestra geografía. Esto último hace que más de una vez sean confundidas las cuencas, y así padecemos casos de graves errores en materia zoogeográfica.

La presente contribución al conocimiento de la fauna de peces argentina, y otras que le seguirán de inmediato, son la continuación natural de un trabajo publicado en esta Revista bajo el título un poco largo, pero deliberadamente comprensivo, de Nuevos conceptos sobre la distribución geográfica de los peces argentinos, basados en expediciones del Museo de La Plata. Sigo aquí el mismo método en las descripciones y aplico el mismo criterio taxonómico y ecológico para alcanzar las conclusiones zoogeográficas. Se verá nuevamente, pues, cuánto nos falta aún para delimitar el contenido de la ictiofauna sudamericana, y cuan necesario es describir minuciosamente y con materiales de procedencia cierta y con conocimiento del ambiente si se quiere iniciarse de una vez en la vía de la identificación sistemática de las formas pero en función del hábitat, como se ve en la obra de Leo Berg, Hubbs, y otros maestros de la ictiología contemporánea.

La privilegiada situación geográfica de Colombia indudablemente exige que las instituciones científicas del país asuman la iniciativa en cuanto a los trabajos sistemáticos biológicos, para así colocarse en la posición natural que les corresponde a la vanguardia de la zoografía neotropical. Debemos considerar esto no solamente como una obligación moral, sino también como un deber imperativo para con la cultura continental, que nos impone nuestra situación estratégica en el punto de adición delas cordilleras de los Andes.