| effects of water ph and calcium concentration on ion balance in fish of the rio negro, amazon. | we examined the effects of acute low-ph exposure on ion balance (na+, cl-, k+) in several species of fish captured from the rio negro, a dilute, acidic tributary of the amazon. at ph 5.5 (untreated rio negro water), the four rio negro species tested (piranha preta, serrasalmus rhombeus; piranha branca, serrasalmus cf. holandi; aracu, leporinus fasciatus; and pacu, myleus sp.) were at or near ion balance; upon exposure to ph 3.5, while na+ and cl- loss rates became significant, they were relative ... | 1998 | 9472808 |
| effects of copper and cadmium on ion transport and gill metal binding in the amazonian teleost tambaqui (colossoma macropomum) in extremely soft water. | metal toxicity in fish is expected to be most severe in soft waters because of the low availability of cations (particularly ca(2+)) to out-compete the metal forms for binding sites on the gills. natural waters in the amazon basin are typically soft due to regional geochemistry, but few studies have focused on metal toxicity in fish native to the basin. we assessed the ionoregulatory effects of waterborne copper (cu) and cadmium (cd) on tambaqui (colossoma macropomum) in extremely soft water (10 ... | 2005 | 16051381 |
| dietary tissue cadmium accumulation in an amazonian teleost (tambaqui, colossoma macropomum cuvier, 1818). | understanding the effects of metal contamination in the amazon basin is important because of the potential impact on this region of high biodiversity. in addition, the significance of fish as the primary source of protein for the local human population (living either alongside the amazon river or in the city of manaus) highlights the need for information on the metal transfer through the food chain. bioaccumulation of metals in fish can occur at significant rates through the dietary route, witho ... | 2007 | 18278317 |
| are rapids a barrier for floodplain fishes of the amazon basin? a demographic study of the keystone floodplain species colossomamacropomum (teleostei: characiformes). | we investigated demographic history and population structuring of colossoma macropomum sampled from 14 localities in the amazon basin and the bolivian sub-basin; the two basins are separated by a series of 16 rapids. although genetically differentiated, ima analyses suggest non-zero bi-directional migration rates, and inter-basin divergence of approximately 17 thousand years ago. analyses in beast indicated that bolivian c. macropomum has been demographically stable except for a moderate populat ... | 2010 | 20362063 |
| morphological and histochemical changes associated with massive infection by neoechinorhynchus buttnerae (acanthocephala: neoechinorhynchidae) in the farmed freshwater fish colossoma macropomum cuvier, 1818 from the amazon state, brazil. | the study describes the morphological changes associated with parasitism by the intestinal acanthocephalan neoechinorhynchus buttnerae in tambaqui juveniles colossoma macropomum farmed in an excavated nursery, in manaus (amazon) in september 2013. after fish biometrics, analysis of macroscopic changes in morphology and counting of parasites, bowel fragments were fixed and submitted to histological and histochemical processing. all fish analyzed had acanthocephalans in the intestine; intestinal l ... | 2017 | 28124738 |
| impacts of stocking on the genetic diversity of colossoma macropomum in central amazon, brazil. | tambaqui (colossoma macropomum) is the main fish species farmed on a commercial scale in northern brazil. in view of the current scenario of brazilian aquaculture, studies on the genetic improvement and reproductive management of captive tambaqui are crucial in identifying the genetic variability of broodstocks and devising management practices. genetic diversity of three tambaqui broodstocks in western amazon was evaluated using molecular markers. fin samples were collected from 89 fish; 38 fro ... | 2016 | 27173205 |
| loss of genetic diversity in farmed populations of colossoma macropomum estimated by microsatellites. | the genetic variability of four colossoma macropomum broodstocks, three from fish farms in different regions and one from the natural environment in brazil, was analyzed using microsatellite markers. the wild progeny (n = 30) were caught in the solimões-amazonas river, at the varzea lakes; this location is used to mature the fish from larvae to juveniles. the three fish farms were selected according to the age of their lineages and broodstock availability: dnocs (n = 21) is located in the ceará ... | 2016 | 26970241 |
| biochemical and behavioral responses of the amazonian fish colossoma macropomum to crude oil: the effect of oil layer on water surface. | the largest brazilian terrestrial province of petroleum mining is located at the margins of urucu river, amazonas. mined crude oil is transported along 400 km across solimões river to be refined in manaus. thus, the main goal of this study was to evaluate the effects of crude oil exposure on biochemical, physiological and behavioral parameters of juveniles of the amazonian fish tambaqui (colossoma macropomum). the toxicity of water-soluble and insoluble oil fractions and the influence of a layer ... | 2015 | 25450912 |
| genetic variation in native and farmed populations of tambaqui (colossoma macropomum) in the brazilian amazon: regional discrepancies in farming systems. | the tambaqui, colossoma macropomum, is the most popular fish species used for aquaculture in brazil but there is no study comparing genetic variation among native and farmed populations of this species. in the present study, we analyzed dna sequences of the mitochondrial dna to evaluate the genetic diversity among two wild populations, a fry-producing breeding stock, and a sample of fish farm stocks, all from the region of santarém, in the west of the brazilian state of pará. similar levels of g ... | 2013 | 24141412 |
| branchiomycosis in tambaqui, colossoma macropomum (cuvier), from the eastern brazilian amazon. | | 2012 | 22524619 |
| mercury distribution in organs of two species of fish from amazon region. | total mercury concentrations were determined in muscle, liver and kidney of cichlia ocellaris and colossoma macropomum sampled at tapajos and carnapijo rivers in amazon ecosystem during the flood period of 2009. in background area the highest levels of mercury were observed in liver of piscivorous (0.3 ± 0.03 ug/g dry wt) and non piscivorous fish (0.20 ± 0.1 ug/g dry wt), but in contaminated area the highest level of mercury in piscivorous fish was detected in liver (0.45 ± 0.27 ug/g dry wt) and ... | 2011 | 21874404 |
| structural indexes and sexual maturity of tambaqui colossoma macropomum (cuvier, 1818) (characiformes: characidae) in central amazon, brazil. | length, weight, structural index and sexual maturity in tambaqui colossoma macropomum were analysed. 449 specimens were obtained from the commercial fishing fleet arriving at manaus harbour from the floodplain areas from may 1992 to july 1993. the objective of this study is to describe changes in structural index during one hidrological cycle and to interpret them according to the water level fluctuations and to also determine the time, reproductive period and length in sexual maturity. sex rati ... | 1999 | 23505652 |