Effects of biodegradable detergents in the accumulation of lipofuscin (age pigment) in gill and liver of two neotropical fish species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Popularion biology of abdominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir (low Tietê river, São Paulo State, Brazil)

The aim of this study is to characterize some population biology parameters of P. squamosissimus, A. altiparanae and S. maculatus, the dominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir, low Tietê river. Fish samplings were performed monthly between September/2002 and August/2003, using gill nets with different mesh sizes. Females of all species have larger standard lengths than males (Mann-Whitney, p < 0.0001), and are more frequent in superior size classes (Kolmogorov-Smirnov, p < 0.0001). All populations presented isometric growth, but differences between males and females were observed. Only P. squamosissimus presented a gender ratio different from 1:1, with a higher proportion of males (1:2, X2, p < 0.05). The onset of gonadal maturation occurs at 15 cm in P. squamosissimus, 9 cm in S. maculatus and at 8.9 cm in A. altiparanae. In all species populations, the adults predominate over juveniles. The allometric condition factor (K) of P. squamosissimus and S. maculatus presented higher values in the periods from March-May and June-August, and A. altiparanae in the period from March-May (Kruskal-Wallis, p < 0.05). These results indicate that the populations successfully exploit the lentic environment, and present life cycle tactics adapted to their particular means of environment occupation.

Aquatic macrophytes as feeding site for small fishes in the Rosana Reservoir, Paranapanema River, southeastern Brazil

In the present investigation we studied the feeding habits of the fishes associated with aquatic macrophytes in the Rosana Reservoir, southeastern Brazil. Twenty fish species were collected during four field trips, regularly distributed across the dry and wet seasons. Focal snorkeling observations of the fishes were made over a total of six hours. Nine species were present in abundances of more than 1% and, therefore, had their feeding habits analyzed. Hemigrammus marginatus, Roeboides paranensis, Hyphessobrycon eques, Astyanax altiparanae, Serrasalmus spilopleura, and Bryconamericus stramineus were predominantly invertivores, with predominance of aquatic insects (Diptera, Ephemeroptera, and Trichoptera immatures) among their food items. The predominantly algivores were Apareiodon affinis, Serrapinnus notomelas, and Satanoperca pappaterra, with high frequency of filamentous blue-green algae, diatoms, clorophyts, and periderm. The different microhabitat exploitation plus diet composition suggests partitioning of resources and absence of food competition among the most representative fish species in the studied community, indicating the importance of the naturalistic approach to fish ecology studies.

Diferenciação gonadal em Piaractus mesopotamicus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aspectos da morfologia na relação presa/predadores de três predadores Characiformes e suas principais presas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistemática de Piabina Reinhardt, 1867 (Ostariophysi: Characidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aplicação das técnicas de microscopia eletrônica de transmissão e histologia para análise de mixozoários parasitos de peixes do Rio Batalha, médio Rio Tietê, São Paulo, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metabolismo do malondialdeído em peixes: implicações na avaliação da peroxidação lipídica como biomarcador de contaminação aquática

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metabolismo do malondialdeído em peixes: implicações na avaliação da peroxidação lipídica como biomarcador de contaminação aquática

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The fish fauna in the fish passage at the Ourinhos Dam, Paranapanema River

The composition and abundance of the fish assemblage were evaluated in the fish ladder of Ourinhos Dam, the newest dam (closed in 2005) in the cascade of dams constructed on the Paranapanema River. Samplings were carried out three times on a diel cycle, in three sampling periods, two in the warm season and one in the cold season of 2008 - 2009. The ladder was closed and emptied and the entire fish assemblage was sampled and identified. Most individuals were released alive downstream of the dam. The assemblage found in the ladder was compared with the fish fauna sampled in the reservoir and in downstream sites, in the same period. Twenty seven species and a total of 4682 individuals were caught in the ladder. Pimelodus maculatus was the only migratory species, which was caught in low number in the ladder (0.04% of the total captured), where small sedentary species predominated. The most abundant species were the non-migratory Apareiodon affinis, Bryconamericus stramineus, Astyanax fasciatus and Parodon nasus. Individuals observed in the ladder's window were moving up-and down the passage. The fish ladder is a microhabitat inhabited by an abundant association of benthic organisms that is probably used as a food resource for the fish assemblage in the ladder. The similarity between the fish fauna in the ladder and that of the Ourinhos Reservoir was low (26%). The species richness of migrants in the stretch between the uspstream reservoir (Chavantes) and the downstream one (Salto Grande), before the Ourinhos dam closure (23 species) was reduced to 16 and 12 species in Salto Grande and Ourinhos reservoirs, respectively, after the dam closure, and to a single species in the ladder.

Población anidante e impacto en la pesca artesanal del cormorán neotropical Phalacrocorax brasilianus (Suliformes:Phalacrocoracidae), en el sitio Ramsar Cerrón Grande, El Salvador.

El cormorán neotropical (Phalacrocorax brasilianus) es una especie de ave acuática abundante en los humedales de El Salvador. La depredación de peces que realiza en los ecosistemas acuáticos, está generando un conflicto con los pescadores que asocian la disminución de la pesca con la conducta depredadora del ave. Entre abril de 2010 a febrero de 2011, se realizó una investigación tendiente a conocer el estado de la población de P. brasilianus en el Sitio Ramsar Embalse Cerrón Grande, El Salvador. El estudio se desarrolló por medio de cinco censos y recolecta de ejemplares, estos últimos se utilizaron para analizar el contenido estomacal. El máximo de ejemplares contabilizados fue de 28,063 individuos y 3,000 parejas reproductoras. Se recolectaron 266 ejemplares, de los cuales, 207 contenían peces en sus estómagos,cuyo peso individual varío de 2 a 307 g ±52 g.Se encontró un total de 1,078 ejemplares de peces correspondiente a diez especies, cuatro de ellas obtuvieron los mayores valores de abundancia: bagre (Cathorops steindachneri)con 29%, seguido por guapote (Parachromis managuensis) con 25%, tilapia (Oreochromis niloticus) con 22% y plateada (Astianax aeneus, Roeboides bouchellei) con 21%. ABSTRACT: The neotropical cormorant (Phalacrocorax brasilianus) is a species of waterfowl abundant in the wetlands of El Salvador. Fish predation on aquatic ecosystems is generating a conflict with fishermen that associating declining fishing with predatory behavior of this bird. From April 2010 to February 2011, an investigation was conducted aimed at knowing the state of the population of P. brasilianus in the Ramsar wetland Cerron Grande, El Salvador. The study was conducted through counting and collecting of birds, to analyze the stomachic contents. The maximum recorded was 28.063 individuals and 3,000 breeding pairs. 266 birds were collected, on 207 it found fish in their stomachs, whose individual weight ranged from 2-307 g ± 52 g. A total of 1,078 fish specimens was found, from ten species, four of them obtained the highest values of abundance: bagre (Cathorops steindachneri) with 29%, followed by guapote (Parachromis managuensis) with 25%,tilapia (Oreochromis niloticus) with 22% and plateada (Astyanax aeneus, Roeboides bouchellei) with 31%.

Estructura y distribución de la íctiofauna de la subcuenca del río Acahuapa, San Vicente, El Salvador

Los ecosistemas fluviales brindan al ser humano importantes bienes ambientales como el abastecimiento de agua para consumo, producción de alimento, generación de energía hidroeléctrica, navegación, recreación y pesca. Así mismo proveen importantes servicios ecosistémicos al regular el clima y los gases del efecto invernadero a través del ciclo hidrológico y el ciclaje de nutrientes (Welcomme 1992). Los peces constituyen uno de los taxones más importantes dentro de los ecosistemas fluviales, además de constituir la mayor cantidad de biomasa animal, desempeñan papeles ecológicos relevantes en el flujo energético de la cadena trófica. Es por ello que en los últimos años ha surgido mayor interés por estudiar a este grupo, lo que ha permitido tener mayor comprensión de su historia natural, sus interacciones y relaciones con los factores ambientales (Miller 2009). La estructura y distribución de la íctiofauna del río Acahuapa fue analizada en 17 sitios dentro del cauce principal y en ríos afluentes. Los muestreos se realizaron en junio, agosto, noviembre del 2011 y febrero y abril del 2012. Se capturó 6,742 individuos distribuidos en 8 órdenes, 13 familias y 32 especies. El 47% de las especies son secundarios, 41% periféricas y 12% primarias. Según clasificación por presencia se obtuvo el 59% de las especies como migratoria, 31% como estacionales y 10% como residentes. Se compararon tallas de 10 especies con mayor abundancia y dominancia por sitios de muestreo donde se observó diferencias significativas de Agonostomus monticola, Astyanax aeneus, Poecilia gillii, Poecilia salvatoris, Rhamdia guatemalensis, Rhamdia laticauda y Sicydium multipunctatum por estratificación de altura. En el caso de A. monticola y S. multipunctatum se observó diferencia de tallas que responde a comportamientos migratorios dentro de la subcuenca.