Navegando por Autor "PRUDENTE, Bruno da Silveira"

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Acesso aberto (Open Access)
Aspectos reprodutivos e alimentares da piranha Serrasalmus gouldingi fink & machado-allison, 1992 (Characiformes: Serrasalmidae) em rios afogados da Amazônia Oriental
(Universidade Federal do Pará, 2012) PRUDENTE, Bruno da Silveira; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The present work aimed to evaluate the reproductive biology, condition factor and feeding ecology of Serrasalmus gouldingi in relation to fluviometric variations of lower Anapu River, in “drowned” rivers of Caxiuanã National Forest, Eastern Amazonia, Pará, Brazil. 275 specimens were bimonthly collected during July 2010 to May 2011 and their total length, total weight, gonad and stomach weight were measured. The gonads were analysed histologically to verify the sex and maturation degree, while the stomachs were evaluated through the identification of the consumed items. The sexual proportion did not differ from 1:1considering the studied period as a whole, however the females were more frequent during the transitional periods of drawdown and filing. The species spawning was “parcelada”, showing two peeks of reproductive activity during the periods which preceded the increase in the local fluviometry. The L50 was estimated in 12.24cm for males and in 16.13cm for females. The species growth was positively alometric, showing a gain of weight in relation to length, and the condition factor, when analysed along the entire sample period, decreased mostly during the spawning. The diet of S. gouldingi was composed of 32 items, grouped in 10 categories. The composition indicated an omnivorous diet with a strong tendency to piscivory, once fish fragments were the most predominant item, followed by fruits and seeds and allochthonus arthropods. The distinct hidrological periods were significantly different in relation to diet composition, although no significant difference was detected among sex and maturation degree. Males and females showed the same variation pattern of repletion index, with a more intense feeding during the increase of the river´s level, while it was less intense during the transitional periods (drawdown and filing). The species also showed some variation in their breadth niche, with lower values during the wet period, attributed to the almost exclusive consumption of fruits and seeds.
Acesso aberto (Open Access)
Feeding ecology of Dash-dot Tetra Hemigrammus belottii (Steindachner 1882) (Characiformes: Characidae) in the streams of the Urucu River basin, central Amazonia, Brazil
(2013-09) GONÇALVES, Andrey Felipe Gomes; PRUDENTE, Bruno da Silveira; CARVALHO FILHO, Fernando da Silva; MONTAG, Luciano Fogaça de Assis
The present study describes aspects of feeding ecology of Dash-dot Tetra Hemigrammus belottii (Characiformes: Characidae) collected in the Urucu River basin in Coari, Amazonas (Brazil), aims to respond the following question: What is the influence of hydrological periods (dry and wet) and spatial distribution in the diet of H. belottii? The specimens were collected between 2006 and 2009 in seven streams in the Urucu basin using standard capture methods. Their stomachs were removed for diet composition analyses. The alimentary items were weighed and identified for subsequent analyzes related to feeding intensity by repletion index (RI%) and importance by alimentary index (AIi%). A total of 227 specimens were analyzed, with a mean standard length of 16.5±5.6 mm. The RI% values indicated that H. belottii fed more intensively during the dry season. The principal items in the diet were Formicidae (IAi% = 69.6), fragments of allochthonous exoskeleton (IAi% = 17.7), and Coleoptera (IAi% = 6.0). The composition of the diet did not vary significantly between seasons or among habitats, which may be related to the abundance of the items exploited by the species throughout the year. Hemigrammus belottii showed a generalist insectivore feeding habits which was mainly composed by allochthonous item.
Acesso aberto (Open Access)
Feeding ecology of Serrasalmus gouldingi (Characiformes: Serrasalmidae) in the lower Anapu River region, Eastern Amazon, Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2016-09) PRUDENTE, Bruno da Silveira; MARINHO, Pedro Carneiro; VALENTE, Roberta de Melo
Studies on feeding ecology of fishes are important to understand the relationship between species and environmental seasonal variations. In tropical rivers, these relationships are mainly modeled by hydrological patterns. Thereby, this study aimed to assess the influence of fluviometric variation and life stage (juveniles and adults) in the feeding ecology of Serrasalmus gouldingi in the lower Anapu River region, located in Eastern Amazon, Pará, Brazil. Specimens were collected bimonthly, considering four different hydrological periods. We assessed the diet composition, feeding intensity and niche breadth of the species. Thirty-two dietary items were identified and grouped into ten categories. A total of 279 stomachs were analyzed, showing a predominance of fish fragments, followed by fruits and seeds. The diet composition of S. gouldingi differed only between drought and flood season, although it did not differ between juveniles and adults. An increase in feeding intensity was recorded during the rise in the water level, with a lower feeding intensity observed during transitional season. Serrasalmus gouldingi showed lower niche breadth during flood season, attributed to the high consumption of fruits and seeds, presenting an omnivorous diet with high tendency towards piscivory. Although less evident than in other Amazon watersheds, the flood pulse in the lower Anapu River region is an important factor influencing the feeding ecology of the species.
Acesso aberto (Open Access)
Influence of the flood pulse on the reproduction of Tocantinsia piresi (Miranda Ribeiro) and Auchenipterus nuchalis (Spix & Agassiz) (Auchenipteridae) of the middle Xingu River, Brazil
(Universidade Federal do Pará, 2015-08) FREITAS, Tiago Magalhães da Silva; PRUDENTE, Bruno da Silveira; OLIVEIRA, Valéria de Albuquerque; OLIVEIRA, Mairo Nazareno Carvalho de; PRATA, Erival Gonçalves; SOUSA, Híngara Leão; MONTAG, Luciano Fogaça de Assis
This study investigates the influence of the flood pulse on the reproductive biology of the auchenipterids Tocantisia piresi (Miranda Ribeiro, 1920) and Auchenipterus nuchalis (Spix & Agassiz, 1829) from the middle Xingu River in the Brazilian state of Pará. The specimens were collected every three months between April, 2012, and January, 2014, covering four distinct periods (flood, ebb, dry, and filling). The sex ratio, size at first maturity, gonadosomatic index, and condition factor were analysed in the two species, and evaluated in the context of the different hydrological periods. A total of 897 specimens of T. piresi were collected, of which 467 were female, and 430 males, and 383 A. nuchalis (286 females and 97 males). In T. piresi, the sex ratio was biased only in the filling and ebb periods, whereas in A. nuchalis, it departed significantly from the expected ratio of 1:1 in all periods, with a predominance of females. The female T. piresi mature at a smaller size than the males, with the opposite of the pattern being recorded in A. nuchalis. In T. piresi, the breeding peak was observed during the low water periods, whereas in A. nuchalis, the peak was recorded in the flood periods. Male and female T. piresi presented similar positively allometric growth rates, whereas in A. nuchalis, growth was negatively allometric, but rates were different between genders. A higher condition factor was recorded in the females of both species during the ebb period. Overall, the results of this study reveals distinct flood pulse effects on the reproductive parameters of the two auchenipterid species studied; for A. nuchalis the spawning seems to happen at the flood period and for T. piresi at the dry season of the middle Xingu River.
Acesso aberto (Open Access)
Influência da exploração madeireira na estrutura do hábitat e diversidade das assembleias de peixes de riachos na amazônia oriental
(Universidade Federal do Pará, 2017-02-17) PRUDENTE, Bruno da Silveira; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
Logging is one of the main activities responsible for the deforestation in the Amazon and is considered an important threat to biodiversity in this region. However, the international market demand for sustainable forest products has resulted in a partial substitution of the conventional exploration method (CE) with the reduced impact exploration (EIR) technique, also considered an important strategy to minimize damages to the Amazon forest and its biodiversity. However, little is known about the effect of these activities on the structure and functioning of riparian ecosystems and their biological communities. In this sense, the present study aimed to evaluate the effect of different methods of logging on the structure of the physical habitat of streams and taxonomic and functional diversity of the fish assemblages of these environments, as well as the elaboration of multimetric indices that allow a rapid and robust evaluation of the ecological integrity of these environments. A total of 47 streams were sampled in the Rio Capim basin, 13 of which were in unexplored areas, 11 in EC areas and 23 in RIL areas. The habitat structure was characterized based on 19 environmental variables, later compared between the different exploration methods. The fish assemblages were sampled using hand net, with a standardized effort, and evaluated as to the composition and different components of the functional diversity. Both methods of logging resulted in changes in the structure of the physical habitat of the streams, however only in areas of CD these changes influenced the taxonomic composition of fish species. In RIL areas only variations in the relative abundance of fish species were observed in relation to the temporal exploitation gradient. Despite the above results, the presence of logging, be it EC or EIR did not affect components of the functional diversity of fish assemblages. However, changes in the habitat of rachis associated with the presence of logging had been directly related to the functional attributes commonly associated with generalist strategies of the species, which are common associated with altered environments. According to the multimetric indexes, streams in RIL areas presented better habitat integrity when compared to streams in CD areas, but still lower than habitat integrity in unexplored streams. On average, EIR areas also presented intermediate values of biotic integrity, however, this differed only in areas of CD. In the studied region, RIL showed to be an interesting strategy to minimize alterations in riach ecosystems resulting from logging. However, the present study was conducted only on a local spatial scale, and considering areas that went through a single exploration cycle. However, changes in physical habitat show that EIR also influence the structure and consequently the ecological integrity of these environments, reinforcing the need for a greater number of studies to understand the real effect of this activity in these environments.
Acesso aberto (Open Access)
Length-weight relationship in ten fish species from the Nhamundá River, the Amazon Basin, Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2017-03) FREITAS, Tiago Magalhães da Silva; SOUZA, João Batista de Souza e; PRUDENTE, Bruno da Silveira; MONTAG, Luciano Fogaça de Assis
Studies on the length-weight relationship (LWR) of fishes are an important tool to describe several biological aspects of the species. Consequently, these studies are relevant due the necessity of comprehension about fish life cycle. Thus, this study aimed to establish the length-weight relationship of the ten most common fish in the Lower Nhamundá River, left tributary of the Amazon River. The capture of fish was conducted in January 2008 using gill nets. A total of 807 individuals, ten species and three Orders (Characiformes, Siluriformes and Clupeiformes) were analyzed. The parameter b varied from 2.680 to 3.698. The LWR were shown for the first time for two species: Anostomoides laticeps and Ageneiosus polystictus. Finally, this research emphasizes the importance of LWR studies in the Amazon and the use of primary data for fisheries management plans.
Acesso aberto (Open Access)
Rapid assessment of the ichthyofauna of the southern Guiana Shield tributaries of the Amazonas River in Pará, Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2020-03) DUTRA, Guilherme Moreira; FREITAS, Tiago Magalhães da Silva; PRUDENTE, Bruno da Silveira; SALVADOR, Gilberto Nepomuceno; LEÃO, Manuela Dopazo de Vasconcellos; PEIXOTO, Luiz Antônio Wanderley; MENDONÇA, Marina Barreira; NETTO-FERREIRA, André Luiz; SILVA, Fabio Roberto Ribeiro da; MONTAG, Luciano Fogaça de Assis; WOSIACKI, Wolmar Benjamin
The Northern Pará Drainage System encompasses the left-bank tributaries of the Amazonas River in the southern Guiana Shield region of Pará state, Brazil. Five of the region’s state protected areas are considered strategic for the conservation of its biodiversity. In the present study, we assessed the ichthyofauna of the five state protected areas of the Northern Pará Drainage System. Seven expeditions were conducted between January 2008 and January 2009, which surveyed stretches of the Cuminá, Cuminapanema, Curuá, Jari, Mapuera, Nhamundá, and Paru rivers. These surveys yielded 286 species belonging to 38 families and eight orders, including seven new records of fish species for Brazil, six of which are also new records for the Amazon basin. Our results provide a valuable database for future research and conservation programs in the protected areas of the region.