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Submitted by (edna.saturno@ufrpe.br) on 2017-02-17T14:12:46Z No. of bitstreams: 1 Natalia Carneiro Lacerda dos Santos.pdf: 836010 bytes, checksum: 936d512ab89df14424b938035835bbcd (MD5) / Made available in DSpace on 2017-02-17T14:12:46Z (GMT). No. of bitstreams: 1 Natalia Carneiro Lacerda dos Santos.pdf: 836010 bytes, checksum: 936d512ab89df14424b938035835bbcd (MD5) Previous issue date: 2011-02-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The fauna of tropical fish is the most abundant and diverse on the planet, with about 4,475 valid species and estimated that the toll could exceed 6,000, with a large number found in Brazil. Since the destruction of habitats is considered a major cause of species extinction, the dams are one of the greatest forms of human intervention in rivers and may lead to the disappearance of species. In spite of major environmental changes imposed by successive dams in major river basins, the understanding of trophic relationships, particularly in top predators, provide consistent information for the implementation of management practices and conservation. The São Francisco River basin is the third largest river basin in Brazil and the first fully inserted within the national territory, representing 7.4% of it. This study was conducted in Sobradinho Reservoir, located in the sub-Middle River and San Francisco was aimed at assessing the diets of five species potentially piscivores, Plagioscion squamosissimus Hoplias malabaricis, Serrasalmus brandtii, and Pygocentrus Piraya Salminus franciscanus, leading into account trophic interrelationships and seasonal changes in water level in the reservoir. Bimonthly collections were made between November 2006 and December 2009 in different parts of the reservoir. Our results show that the five species are potentially piscivores, but showed low levels of dietary overlap and similarity, and were not observed significant seasonal changes in diet of the species. / A fauna de peixes tropicais é a mais abundante e diversificada do planeta, com aproximadamente 4.475 espécies válidas e uma estimativa que esse número possa ultrapassar os 6.000, sendo um grande número encontrado no Brasil. Uma vez que a destruição de habitats é considerada uma das principais causas de extinção de espécies, os represamentos constituem umas das maiores formas de intervenção antrópica em rios, podendo levar ao desaparecimento de espécies. A despeito das grandes alterações ambientais impostas pelos sucessivos represamentos nas grandes bacias hidrográficas brasileiras, o entendimento das relações tróficas, sobretudo em predadores de topo, fornecem informações consistentes para a implementação de práticas de manejo e conservação. A bacia do rio São Francisco é a terceira maior bacia hidrográfica brasileira e a primeira totalmente inserida dentro do território nacional, correspondendo a 7,4% do mesmo. O presente estudo foi desenvolvido no reservatório de Sobradinho, localizado na região do sub-médio rio São Francisco e teve como objetivo principal avaliar a dieta de cinco espécies potencialmente piscívoras, Plagioscion squamosissimus, Hoplias malabaricis, Serrasalmus brandtii, Pygocentrus Piraya e Salminus franciscanus, levando-se em consideração interelações tróficas e mudanças sazonais no nível hidrológico no reservatório. Foram realizadas coletas bimestrais entre novembro de 2006 e dezembro de 2009 em diferentes trechos do reservatório. Os resultados observados mostram que as cinco espécies são potencialmente piscívoras, porém apresentaram baixos valores de sobreposição alimentar e similaridade, além de não terem sido observadas mudanças sazonais significativas na dieta das espécies.

The purpose of this research was to develop and standardize a novel feeding bioassay with Macrobrachium rosenbergii for use in the laboratory and allowing it to be easily deployed under field conditions. Standardization of the test aimed to minimize feeding rate variations and to ensure that subsequent statistical analyses have sufficient power to consistently detect changes in feeding rates. These were accomplished through the development of a post-exposure feeding toxicity test under laboratory, microcosm and in situ/field conditions. This procedure was proven to be repeatable and economical. M. rosenbergii as test animals were available in terms of quantity and uniformity in sizes. The standard guidelines and procedures for M. rosenbergii bioassay developed from this study include the size of test animals (9-10 mm), density in exposure containers (10 animals in 500 mL of medium in the laboratory, 10 animals in field chambers with 98.6 mL volume), exposure time (24 hours), feeding period for post-exposure feeding (4 hours) and number of replicates for the feeding test (10 replicates for individual measurements). The tiered approach used in the preliminary risk assessment of pesticide using TOXSWA was capable of screening the risk level of pesticide in the study area, identifying profenofos and dimethoate as test chemicals for the lethal and sub-lethal experiments. This model was beneficial in the preliminary risk assessment of pesticides in the tropics, since it was not necessary to set up laboratory work. This method could also provide preliminary data to support the environmental planner and decision/policy maker. This is an alternative way to develop a cost efficient model to inform and warn the risk of pesticide use. The effects of pH, temperature and hardness on control post-exposure feeding rates of M. rosenbergii were assessed and indicated that M. rosenbergii was very sensitive to acidic and basic conditions. The use of post-exposure feeding inhibition as the endpoint under laboratory conditions revealed that prawns were sensitive to pesticides (chlorpyrifos, dimethoate and profenofos) and a heavy metal (zinc). Post-exposure feeding rate inhibition could be used as a sublethal endpoint as the EC50 values obtained for chlorpyrifos and zinc were lower than their lethal levels. Mortality of prawn was also another endpoint used to define the toxicity of pesticides such as carbendazim, in which mortality occurred during exposure, but post-exposure feeding rate of the surviving animals did not decrease. The microcosm experiments were able to link the laboratory toxicity tests and the effects observed in the field. Microcosm studies provided another dimension to studies looking at pesticide effects on aquatic systems. In this research, carbendazim affected feeding and survival rates in the microcosm set-up but in the laboratory only mortality showed a significant difference (P < 0.05). In situ bioassays were able to show the effects of pesticides on post-exposure feeding rates using the methods developed. Post-exposure feeding rates were significantly lower than control in farms using pesticides while in uncontaminated sites (pesticide-free), the post-exposure feeding rates did not decrease. However, mortality was observed even in the uncontaminated sites which could be attributed to other factors such as low dissolved oxygen and presence of some other unidentified chemical substances. The degree of mortality and the effect on feeding rates depends not only on the type and concentration of the known pesticide but also on water quality parameters. The basic methods developed for in situ bioassay from this research is a simple, easy and fast way to determine the effect of pesticides because the results can be seen in the field. The procedures developed and results obtained from this study can be used as a basis for further toxicity studies on M. rosenbergii and other potential tropical species.

Die Osteoglossomorpha stellen eine basale Gruppe der Teleostei dar mit einer Mischung von plesiomorphen und apomorphen Merkmalen bezogen auf Reproduktion und ontogenetische Entwicklung. Bezüglich reproduktiver Gilden und ontogenetischer Entwicklung gibt es immer noch nur begrenzte Daten zu dieser Gruppe. Der größte Teil tiefer gehender Studien bezieht sich auf Mormyriden, detaillierte Beschreibungen und experimentelle Daten sind kaum vorhanden bei den anderen Gruppen sowie bei Notopterus notopterus und Osteoglossum bicirrhosum. Im Rahmen dieser Untersuchung wird zum ersten Mal eine detaillierte Beschreibung der ontogenetischen Entwicklung dieser beiden Arten auf der Basis von Laborzuchten vorgestellt. Nur bei N. notopterus gelangen Zuchtexperimente unter Laborbedingungen. Die experimentellen Daten zeigten, dass die Umweltparameter abnehmende Leitfähigkeit, Erhöhung des Wasserstandes und leichte Temperaturvariation keinen Einfluss auf Gonadenentwicklung oder Balzverhalten bei N. notopterus hatten. Die frisch abgelegten, klebrigen Eier von 3.8-4 mm Größe werden vom Männchen bis zum Schlupf bewacht. Die Eihülle besitzt äußere Rillen, die ringförmig um die Mikropyle herum angeordnet sind. Das Schlüpfen erfolgt im Alter von 168-204 Stunden. In dieser Studie wird zum ersten Mal eine Methode zur erfolgreichen Aufzucht von O. bicirrhosum unter Laborbedingungen bei 28 °C vorgestellt. Die nicht-klebrigen Eier von 12 mm Größe besitzen eine transparente Eihülle. Das Schlüpfen erfolgt im Alter von 162-166 Stunden und die geschlüpften Embryonen haben eine Länge von 16 mm. Bei O. bicirrhosum findet sich keine Larval-Periode; auf die Embryonal-Periode folgt sofort die Juvenil-Periode: Die Ontogenese kann somit als direkte Entwicklung klassifiziert werden. N. notopterus hingegen ist gekennzeichnet durch eine intermediäre Entwicklung unter Bezug auf Reproduktionsstrategien da sie eine höhere Anzahl von mittelgroßen Eiern produzieren bei gleichzeitiger Brutpflege. / The Osteoglossomorpha represent a basal group of teleostean fish comprising taxa with a mixture of both plesiomorphic and apomorphic characters of reproduction and ontogenetic development. Concerning reproductive styles and ontogenetic development of this group, there are still very limited data available so far. Most in depth studies are available for mormyrids, but detailed descriptions and experimental data remain scarce in the other groups as in Notopterus notopterus and Osteoglossum bicirrhosum. This study will describe in detail for the first time the ontogenetic development of these two species in laboratory-reared specimens. Only N. notopterus succeeded in the breeding experiment. Experimental data demonstrated that the environmental factors decreasing conductivity, slight variation of temperature, and water level have no influence on gonad development or courtship behaviour in N. notopterus. Newly spawned 3.8–4 mm adhesive eggs are guarded by the male until hatching. The egg envelope has external ridges, which are centred around the micropyle. Hatching occurs within 168–204 hours. For the first time, this study describes a method of successfully raising O. bicirrhosum at 28 °C under laboratory conditions. The non-adhesive eggs measure 12 mm with a transparent egg envelope. Hatching occurs around 162–166 hours and newly hatched embryos measure 16 mm. Actually there is no larval period found in O. bicirrhosum. The embryonic period is directly followed by the juvenile period and ontogeny can be characterized as direct development. N. notopterus is classified as intermediate species in an interpretation at reproductive strategies since they produce a higher number of medium-sized eggs and show parental care.

Little is known regarding the impact excessive waterborne metals, like copper (Cu), have on tropical freshwater species. Zebrafish (Dania rerio) only recently became popular as a tool for environmental monitoring, due to their fully sequenced genome. Despite this, little was known regarding the ionoregulatory physiology of zebrafish. I first examined the impact softwater acclimation has on the ionoregulatory capacity of zebrafish, and identified a high degree of phenotypic plasticity associated with changes in both gene and protein expression, which highlighted the need for proper experimental design for studies involving pre-acclimation to softwater. I then examined the acute and chronic effects of waterborne Cu exposure under the influence of both softwater conditions and the addition of protective ions (Na+ & Ca2+) . On an acute timeframe, I found that Na+ provided a greater protective effect than Ca2+ in reducing Cu uptake, which was mimicked during chronic exposure, although the transcriptional effects were not as clear cut. I found that although Na+ and Ca2+ provided protective effects from Cu accumulation, there were still tissue specific and global changes at the transcript level, as determined by microarray analysis. Furthemore, this set of experiments identified the metal- and stress- induced transcriptional effects due to Cu exposure, which is key to identifying gene endpoints of chronic Cu exposure. A final experiment went further and looked at the effects of mixed metal contamination, examining chronic waterborne Cu exposure with interactive effects of elevated dietary Fe on gene expression and tissue metal accumulation. Not only did this experiment highlight that gene expression is not necessarily reflected in protein abundance/activity, but also demonstrated that high dietary Fe can significantly alter the transcriptional expression pattern of Cu transporters in the gill, liver, and gastrointestinal tract. This thesis has made significant steps in identifying viable gene endpoints of Cu toxicity. / Thesis / Doctor of Philosophy (PhD)