Dieta de Pseudocorynopoma doriae (Characiformes: Characidae ) en el Arroyo La Choza, Buenos Aires, Argentina

Fil: Brancolini, Florencia. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Maroñas, Miriam Edith. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Sendra, Eduardo Daniel. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Fish-killing diatom bloom in an urban recreational pond: An index case for a global warming scenario?

By the end of the exceptionally warm and stormy autumn of 2018, a fish kill occurred in a small hypertrophic pond located in a recreative green area in Buenos Aires (BA, Argentina). As there were no visible signs of an algal bloom, the causes for the die-off were investigated. On 1st June, the pond was sampled while fish, mostly Bryconamericus iheringii (Characidae) and Australoheros facetus (Cichlidae) were still dying. Despite low turbidity (18.9 NTU) and chlorophyll a concentration values (15.90 µg/L) as compared to similar BA waterbodies, a heavy bloom of planktonic araphid diatoms (161,600 ind/mL) was detected, mainly caused by Fragilaria saxoplanctonica (Fragilariaceae), Pseudostaurosira neoelliptica (Fragilariaceae) and Ulnaria cf. acus (Fragilariaceae). Previous records of high abundances of these or closely related planktonic diatoms around the world were associated with increased temperature and nutrient content, yet they did not cause other than nuisance blooms. Fish necropsy showed good body condition except for gill damage and mucus accumulation due to a large amount of frustules of these species, mainly P. neoelliptica, interspersed in the gill filaments. Although this is a common cause for die-offs in marine fish farms, it is unprecedented in freshwater systems, and particularly in urban waterbodies. Conversely to more common –and foreseeable-summer cyanobacterial blooms in these systems, this phenomenon was triggered by an autumnal weather anomaly. This fact is crucial, as non-summer heat waves and heavy storms are predicted to increase in frequency and intensity over the subtropical regions, yet their ecological consequences are less perceived, seldom studied, and far from understood. This could be the first documented case of many to occur in such heavily eutrophicated environments unless effective strategies for eutrophication control and management are taken.Fil: Casa, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Brancolini, Florencia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Mielnicki, Diana Matilde. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Mataloni, Maria Gabriela. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Actinopterygii, Siluriformes, Loricariidae, <i>Hypostomus aspilogaster</i> (Cope, 1894) : Distribution extension and first record for Argentina

The present work extends to Argentina the distribution of Hypostomus aspilogaster originally described from Uruguay River in southern Brazil. The examined specimens were sampled in the stream Mandisoví Grande, affluent of Uruguay River in Entre Ríos province, and in Punta Lara, from Río de la Plata basin, in Buenos Aires province, Argentina. This represents the first country record for this species.Facultad de Ciencias Naturales y Muse

Actinopterygii, Siluriformes, Loricariidae, Hypostomus aspilogaster (Cope, 1894). Distribution extension and first record for Argentina

The present work extends to Argentina the distribution of Hypostomus aspilogaster originally described from Uruguay River in southern Brazil. The examined specimens were sampled in the stream Mandisoví Grande, affluent of Uruguay River in Entre Ríos province, and in Punta Lara, from Río de la Plata basin, in Buenos Aires province, Argentina. This represents the first country record for this species. © 2011 Check List and Authors.Fil: Cardoso, Yamila Paula. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brancolini, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Protogino, Lucila Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Lizarralde, Marta Susana. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Dieta de <i>Pseudocorynopoma doriae</i> (Characiformes: characidae) en el arroyo La Choza, Buenos Aires, Argentina

In this paper the objective is to characterize the Pseudocorynopoma doriae diet of the La Choza stream, assessing the relative importance of the contribution of the terrestrial environment to it and compare it with mesopotamian lotic environments. In all environments studied this species presented an invertivorous feeding. In the case of La Choza stream, comparison of diet between sampling dates showed a low degree of similarity, nevertheless the food items were all related to the surface film of water. Latter also is found in mesopotamian streams. When comparing the results of the percentage composition of the diet of P.doriae, it has shown that in mesopotamian environments diet is dominated by allochthonous insects while in the case of La Choza, dominance is shared with autochthonous items.Facultad de Ciencias Naturales y Muse

Dieta de <i>Pseudocorynopoma doriae</i> (Characiformes: characidae) en el arroyo La Choza, Buenos Aires, Argentina

In this paper the objective is to characterize the Pseudocorynopoma doriae diet of the La Choza stream, assessing the relative importance of the contribution of the terrestrial environment to it and compare it with mesopotamian lotic environments. In all environments studied this species presented an invertivorous feeding. In the case of La Choza stream, comparison of diet between sampling dates showed a low degree of similarity, nevertheless the food items were all related to the surface film of water. Latter also is found in mesopotamian streams. When comparing the results of the percentage composition of the diet of P.doriae, it has shown that in mesopotamian environments diet is dominated by allochthonous insects while in the case of La Choza, dominance is shared with autochthonous items.Facultad de Ciencias Naturales y Muse

Dieta de <i>Pseudocorynopoma doriae</i> (Characiformes: characidae) en el arroyo La Choza, Buenos Aires, Argentina

In this paper the objective is to characterize the Pseudocorynopoma doriae diet of the La Choza stream, assessing the relative importance of the contribution of the terrestrial environment to it and compare it with mesopotamian lotic environments. In all environments studied this species presented an invertivorous feeding. In the case of La Choza stream, comparison of diet between sampling dates showed a low degree of similarity, nevertheless the food items were all related to the surface film of water. Latter also is found in mesopotamian streams. When comparing the results of the percentage composition of the diet of P.doriae, it has shown that in mesopotamian environments diet is dominated by allochthonous insects while in the case of La Choza, dominance is shared with autochthonous items.Facultad de Ciencias Naturales y Muse

Peces y ambientes del Bajo Delta bonaerense

La mayor riqueza de especies de peces de nuestro país, se encuentra en la cuenca del río Paraná (López et al., 2005). Esta cuenca, es la segunda en importancia en América del Sur, en cuanto a caudal y área drenada (Welcomme, 1985), y una de las primeras por la extensión y el bajo grado de alteración de los humedales de su planicie de inundación (Neiff y Malvárez, 2004). Gran parte de los paisajes de la región, están conformados por depósitos litorales originados por procesos de ingresión y regresión marina, ocurridos durante el Holoceno Medio (aproximadamente 5000 años antes del presente AP), a los que se les superponen fases fluviales y deltaicas pasadas y actuales (Iriondo y Scotta, 1979; Cavallotto et al., 2005). La región denominada Bajo Delta, se ubica en el sistema de paisaje denominado “Humedales del Delta del Río Paraná” (Benzaquén et al., 2013), el cual comprende al delta insular. Este incluye a todas las islas que tienen una morfogénesis estrictamente deltaica, y que se han formado por el continuo depósito de sedimentos aportados por los ríos Paraná y Uruguay en el Río de la Plata, proceso que continúa en la actualidad con una tasa que fue estimada en 70 m por año (Iriondo y Scotta, 1979). La porción más distal, es la llamada Frente de Avance, y su desarrollo ha tenido lugar en los últimos 110 años (Sarubbi et al., 2006).Instituto de Limnología "Dr. Raúl A. Ringuelet

Ictiofauna del arroyo La Choza, cuenca del Río de la Reconquista (Buenos Aires, Argentina)

Fil: Colautti, Darío César. Instituto Tecnológico Chascomús (IIB-IINTECH/UNSAM-CONICET)Fil: Maroñas, Miriam Edith. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA); Facultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Sendra, Eduardo Daniel. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA); Facultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Protogino, Lucila Cristina. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA); Facultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Brancolini, Florencia. Universidad CAESE; Buenos AiresFil: Campanella, Daniela. Instituto Tecnológico Chascomús (IIB-IINTECH/UNSAM-CONICET

Hypostomus formosae, a new catfish species from the Paraguay River Basin with redescription of H. boulengeri (Siluriformes: Loricariidae)

Hypostomus formosae n. sp. is described for the Paraguay river basin, Argentina. It can be distinguished from all other Hypostomus by having the combination of the following features: dorsum of head, body and all fins bright grey covered by numerous rounded dark dots and 11 ventral plates between end of anal-fin base and caudal fin (vs. more than 11). In addition, the new species is distinguished from the most similar sympatric species, H. boulengeri by slightly higher cleithral width, dorsal-fin base length, caudal-peduncle depth and by narrower caudal-peduncle length, eye diameter and mandibulary ramus length. Hypostomus formosae belongs to the Amazonian "H. plecostomus species group" and our molecular phylogenetic results show that it is the sister species to the Guianese H. plecostomus, highlighting past inter-basin ichtyofauna exchanges. We also provide detailed record of H. boulengeri for the first time in Argentina, collected in Paraguay river, at Formosa city.Instituto de Limnología "Dr. Raúl A. Ringuelet