Made available in DSpace on 2015-04-22T22:12:46Z (GMT). No. of bitstreams: 1 Jefferson Lemos.pdf: 576722 bytes, checksum: a07c5844d483e717217e6bc8fd31e3fb (MD5) Previous issue date: 2011-06-01 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work studied the parasite fauna and the health status of cururu stingray, Potamotrygon cf. hystrix, the middle Rio Negro, Amazonas, Brazil, during a hydrological cycle and stages of the extraction of ornamental fish (nature, post-transport, 48 hours in quarantine and 15 days of quarantine), through the identification and quantification of parasites and the correlation of parasite abundance with health indicators for fish. The parasitic index and health indicators were assessed in relation to water level and between stages. The health indicators used included the relative condition factor (Kn), the hepato somatic index (HSI), spleen (SSI) and epigonal organ (ISEO), and erythrocyte parameters and biochemical blood analysis. We found two species of Cestoda, unidentified specimens of Nematoda and Achantocephala, two species of Monogenoidea and five species of Branchiura. The Monogenoidea and Cestoda occurred in all periods of the hydrological cycle, the Nematoda and Branchiura not occurred at high water. The Acanthocephala were recorded during periods of drought and flood. The abundance of Cestoda positively correlated with the HSI, ISEO, hematocrit, erythrocyte number, hemoglobin and glucose. The abundance of Monogenoidea and Branchiura positively correlated with hematocrit and MCH, respectively. In the post-transport were observed critical values in dissolved oxygen and high ammonia levels in water. The Kn in nature was higher than post-transport, 48 hours in quarantine and 15 days of quarantine. The SSI and HSI were minor in nature. There was a reduction in red blood cells, hemoglobin and MCHC, and increased MCV, post-transport in relation to nature. In 48 hours and 15 days of quarantine, there was an increase in hemoglobin and MCH, besides the reduction in MCV in relation to post-transport. Glucose and total protein were lower in post-transport in relation to nature and 48 hours of quarantine, respectively. The Cestoda and Monogenoidea showed the highest prevalences in nature and post-transport. Cestoda abundance was higher in nature and post-transport in relation to 48 hours and 15 days of quarantine. Monogenoidea intensity was higher in post-transport than in other stages. It s the first seasonal study of parasites at a stingray of middle Rio Negro and pioneer in correlate the parasite abundance with health indicators in potamotrygonids. The post-transport was the most critical stage in the chain to the extractive cururu stingray. / Este trabalho estudou a fauna parasitária e o estado de saúde da arraia cururu, Potamotrygon cf. histrix, do médio Rio Negro, Amazonas, Brasil, durante um ciclo hidrológico e em etapas da cadeia extrativista de peixes ornamentais (natureza, pós-transporte, 48 horas de quarentena e 15 dias de quarentena), por meio da identificação e quantificação dos parasitos e a correlação da abundância parasitária com os indicadores de saúde para peixes. Os índices parasitários e os indicadores de saúde foram avaliados em relação ao nível hidrológico e entre as etapas citadas acima. Os indicadores de saúde utilizados incluíram o fator de condição relativo (Kn), a relação somática do fígado (RHS), baço (RES) e órgão epigonal (RSOE), além de parâmetros eritrocitários e da bioquímica do plasma. Foram encontradas duas espécies de Cestoda, espécimes não identificadas de Nematoda e Achantocephala, duas espécies de Monogenoidea e cinco espécies de Branchiura. Os Cestoda e Monogenoidea ocorreram em todos os períodos do ciclo hidrológico, os Nematoda e os Branchiura não ocorreram na vazante. Os Acanthocephala foram registrados nos períodos de seca e enchente. A abundância de Cestoda correlacionou positivamente com a RHS, RSOE, hematócrito, número de eritrócitos, níveis de hemoglobina e glicose. A abundância de Monogenoidea e Branchiura correlacionou positivamente com o hematócrito e o HCM, respectivamente. No pós-transporte observaram-se valores críticos no oxigênio dissolvido e níveis elevados de amônia na água. O Kn na natureza foi maior em relação ao pós- transporte, 48 horas de quarentena e 15 dias de quarentena. As RES e RHS foram menores na natureza. Houve redução no número de eritrócitos, concentração de hemoglobina e CHCM, além de aumento do VCM, no pós-transporte em relação à natureza. Em 48 horas e aos 15 dias de quarentena, houve aumento na hemoglobina e HCM, além de redução no VCM em relação ao póstransporte. Glicose e proteínas totais foram menores no pós-transporte em relação à natureza e 48 horas de quarentena, respectivamente. Os Cestoda e Monogenoidea apresentaram as prevalências mais elevadas na natureza e no pós-transporte. A abundância de Cestoda foi maior na natureza e no pós-transporte em relação às 48 horas e 15 dias de quarentena. A intensidade de Monogenoidea foi maior no pós-transporte que nas demais etapas. Este é o primeiro estudo sazonal de parasitos em uma arraia do médio Rio Negro e pioneiro ao correlacionar a abundância parasitária com indicadores de saúde em potamotrigonídeos. O pós-transporte foi a etapa mais crítica da cadeia extrativista para a arraia cururu.

Made available in DSpace on 2016-06-02T19:31:37Z (GMT). No. of bitstreams: 1 DissJES.pdf: 3251640 bytes, checksum: 1a2925395aad5a4359dc8d598a17edc7 (MD5) Previous issue date: 2007-02-23 / Financiadora de Estudos e Projetos / The Cichla kelberi population was characterized in terms of sexual proportion, size structure and some reproductive aspects. The collects were made in two distinct periods. The first, from November 2002 to November 2003 and the second, from December 2004 to May 2006. The sexual proportion showed significantly difference from 1:1 with predominance of females. Total length varied from 3.4 to 40.1cm, with large frequency on the small sized classes. These smallest individuals occurred around all the year, but mainly in the warmer months. Females and males reached similar maximum length. Individuals with Mature or Partial Spent gonads occurred mainly from November to April, indicating that Cichla kelberi has a long reproductive period, a biological evidence that it is a species well adapted in this reservoir, showing partial spawning and an absolute fecundity ranging from 6089 to 6908 oocytes. / Foi caracterizada a composição da população de Cichla kelberi quanto à proporção sexual, composição em comprimento e algumas características reprodutivas. As coletas foram realizadas em dois períodos. O primeiro, de novembro de 2002 a novembro de 2003 e o segundo, de dezembro de 2004 a maio de 2006. A proporção sexual foi significativamente diferente de 1:1, com predomínio de fêmeas. Os comprimentos totais variaram de 3,4 a 40,1cm, com altas freqüências nas classes de menor tamanho. A ocorrência de indivíduos nas menores classes deu-se ao longo de todo o ano, com maior incidência nos períodos mais quentes. Fêmeas e machos atingem comprimentos máximos similares. Indivíduos com gônadas Maduras ou Semi Esgotadas ocorreram com maior freqüência de setembro a abril, indicando que Cichla kelberi apresenta um longo período reprodutivo, uma condição biológica que indica a boa adaptação da espécie neste reservatório. A desova é do tipo parcelada e com fecundidade absoluta de variando de 6089 a 6908 ovócitos.

Although U.S. commercial catfish aquaculture ponds are in temperate regions and experience cool to cold temperatures during the winter, few studies have investigated the effects of low temperatures on catfish physiological processes. Therefore, growth, metabolism, swimming performance, and blood variables were compared between channel (Ictalurus punctatus), blue (I. furcatus), and hybrid (I. furcatus x I. punctatus) catfish at 10 and 20°C. Accelerometers were also used to evaluate relationships among acceleration, metabolism, and tail beat frequency (TBF) during swimming performance tests. Channel catfish experienced the greatest growth, yet growth was diminished across all fish types at 10°C. Metabolic processes, swimming performance, and related blood variables were also diminished at 10°C. Relationships among acceleration, metabolism, and TBF were found indicating cold temperatures inhibit maximum production in catfish and provide initial steps for creating holistic bioenergetic models for further application.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-11-30T12:57:40Z No. of bitstreams: 1 GRAZIELA RODRIGUEZ RAMALHO_.pdf: 9033106 bytes, checksum: f9bb8db7a276b0a033851c0b02834eea (MD5) / Made available in DSpace on 2015-11-30T12:57:40Z (GMT). No. of bitstreams: 1 GRAZIELA RODRIGUEZ RAMALHO_.pdf: 9033106 bytes, checksum: f9bb8db7a276b0a033851c0b02834eea (MD5) Previous issue date: 2015-08-07 / Nenhuma / Estudos de reprodução possibilitam determinar tipo, local, época de desova e tamanho mínimo dos indivíduos envolvidos neste processo. Neste sentido o objetivo deste estudo foi descrever os aspectos reprodutivos de quatro populações de peixes (Corydoras paleatus, Astyanax jacuihensis, Bryconamericus iheringii e Cyanocharax alburnus) da parte baixa da bacia do rio Piratini/RS. As coletas foram realizadas de janeiro a março de 2014, em sete locais de amostragens. As capturas foram realizadas com rede de arrasto e puçá. Os espécimes foram eutanasiados em uma solução de Eugenol, para cada litro de água por 1 minuto. Posteriormente, o material foi fixado em formol 10%, por 48h, e conservado em etanol 70%. A identificação no nível de espécie ocorreu no Laboratório de Ictiologia da UNISINOS. Para a análise da biologia reprodutiva dos peixes foram analisados os dados morfométricos e o grau de maturação gonadal. Os sexos foram identificados para todos os exemplares das quatro espécies, baseando-se numa escala de cinco estádios: Estádio A/Imaturo; B/Em Maturação; Estádio C/Maduro e Estádio D/Esvaziado. Os resultados mostraram um total de 727 indivíduos, pertencentes a 6 ordens, 12 famílias, 28 gêneros e 38 espécies. Em relação aos índices de diversidade, Shannon-Wiener, equitabilidade e dominância, as ordens dos Characiformes e Siluriformes dominaram em riqueza. Para os Siluriformes C. paleatus, a análise da proporção sexual não diferiu significativamente, sendo 1:1, enquanto que para os Characiformes, A. jacuihensis, B. iheringii e C. alburnus, houve diferenças significativas de 3:1, com predominância de fêmeas para estas três espécies. A distribuição do fator de condição por local de captura apresentou forte elevação e variação às espécies analisadas, os locais 10 e 24, apresentando crescimento alométrico negativo (b<3). O crescimento alométrico positivo (b>3) foi registrado nos locais 12, 21, 15, 35, 45, 53 e 80 em relação à espécie C. paleatus, assim como, os locais 12, 21, 23, 33 e 53 referente à ordem dos Characiformes. Já nos locais 11, 12, 33 e 53, os Characiformes apresentaram crescimento alométrico negativo (b<3). As fêmeas em Estádio/C, foram encontradas nos locais 10, 15, 24, 45, 53 e 80, correspondente a C. paleatus e para a ordem dos Characiformes registrou-se baixo percentual maioria dos locais amostrados. A distribuição da frequência por classe de comprimento padrão evidenciou que a amplitude de variação de comprimento está compreendida para os Characiformes entre 35 mm a 60 mm, e para os Siluriformes entre 20 mm a 60 mm. Esses resultados são importantes na compreensão ecológica e reprodutiva de peixes do rio Piratini. / Reproduction studies make it possible to determine type, location, spawning season and minimum size of individuals involved in this process. In this sense aim of this study was to describe the reproductive aspects of four populations of fish (Corydoras paleatus, Astyanax jacuihensis, Bryconamericus iheringii and Cyanocharax alburnus) the lower part of the Piratini/RS River basin. Sampling was carried out from January to March 2014 in seven places of sampling. Catches have been taken with trawl and hand net. The specimens were euthanized in a solution of eugenol for each liter de water for 1 minute. Subsequently, the material was fixed in 10% formalin for 48 hours and preserved in 70% alcohol. The identification at the species level was the Ichthyology Laboratory of UNISINOS. To analyze the reproductive biology of fish were analyzed morphometric data and the degree of maturation. The sexes were identified for all copies of the four species, based on a five-stage scale: Step A/immature; B/in maturation; Stage C/Mature Stage D/exhausted; Stadium E/Home. The results showed a total of 727 individuals belonging to 6 orders, 12 families, 28 genera and 38 species. Regarding the diversity index, Shannon-Wiener, equitability and dominance, the orders of Characiformes and Siluriformes dominated in wealth. For Siluriformes C. paleatus, analysis of the sex ratio did not differ significantly, 1: 1, whereas for Characiformes, B. iheringii and C.alburnus, significant differences of 3: 1 with the predominance of Female for these three species. The distribution of the capture site condition factor showed a strong increase and change the analyzed species, local 10:24, with negative allometric growth (b <3). The positive allometric growth (b> 3) was recorded in 12 sites, 21, 15, 35, 45, 53 and 80 in relation to the species C. paleatus, as well as the locations 12, 21, 23, 33 and 53 concerning order of Characiformes. Already at the locations 11, 12, 33 and 53, the Characiforms were negative allometric growth (b <3). Females in Stadium/C were found in places 10, 15, 24, 45, 53 and 80, corresponding to C. paleatus and the order of Characiformes enrolled low percentage majority of sites sampled. The frequency distribution of standard lengths for class showed that the range of length variation for Characiforms is comprised between 35 mm to 60 mm, and the Siluriformes between 20 mm to 60 mm. These results are important in ecological understanding and reproductive Piratini river fish.

The objectives of this study were to investigate the difference and interaction of mercury (Hg) and selenium (Se) among fish species and tissues. In addition, by comparing with the detected concentrations in other regions, it would be possible to evaluate the pollution status. In the meanwhile, this study analyzed the edibility of the fish, the interaction between Hg and Se as well as their impacts on fish growth. Ten species of fish, including tenpounder (Elops machnata), fourlined terapon (Pelates quadrilineatus), whipfin silverbiddy (Gerres filamentosus), common ponyfish (Leiognathus equulus), Hamilton's thryssa (Thryssa hamiltonii), tilapia (Orechromis niloticus), western Pacific gizzard shad (Nematalosa come), large-scaled mullet (Liza macrolepis), flathead mullet (Mugil cephalus) and milkfish (Chanos chanos), and 20 sediment samples were collected from September to October of 2003 at the reservoir adjacent to a chlor-alkali plant, which had been abandoned for 22 years in Tainan City. Total mercury (THg) and organic mercury (OHg) concentrations were determined in fish muscles, livers, kidneys, gonads, gills and sediment samples. Besides, Se concentrations were also analyzed in fish muscles and livers. Concentrations (mg/kg dry wt.) of THg and OHg in sediment were 43.2¡Ó23.4(mean¡Ósd) and 0.013¡Ó0.008, respectively. THg, OHg and Se concentrations (mg/kg wet wt.) in fish muscles were 0.432¡Ó0.360, 0.305¡Ó0.206 and 0.126¡Ó0.030, similar to the concentrations in other chlor-alkali polluted regions. With the diet habit of Taiwanese, the Hg concentrations of muscles in the seven fish species exceeded the limit of Hg which was allowed to be consumed by humans. THg and OHg concentrations in the fish muscles showed significant species difference. Obviously, the concentrations in carnivorous fishes were higher than those in omnivorous and herbivorous fishes. The OHg concentrations of fish livers and kidneys were highest in carnivorous fishes, but the THg concentrations were higher in omnivorous fishes than in that of carnivorous and herbivorous fishes. Besides, Se concentrations in fish muscles and livers also showed significant species difference, but did not show relation with the feeding habit of fishes. The Hg levels among fish tissues were highest in livers or kidneys, followed by gonads and muscles, lowest in gills. Generally speaking, Se levels were higher in livers than in muscles. The liver THg concentrations of tilapia reached 10 mg/kg wet wt. Their muscle THg concentrations decreased suddenly and maintained at a level about 0.4 mg/kg wet wt. Meanwhile, the liver inorganic Hg and Se concentrations increased with fish weight, while the liver OHg concentrations did not show such a trend but stay at a low level. High Hg concentrations in the fish tissues resulted in adverse effects on fish health. High Hg concentrations in muscles and livers caused heptasomatic index to decrease in western Pacific gizzard shad and milkfish, and condition factor declined in tilipia. Moreover, gonasomatic index remained low while the Hg concentrations of muscles, livers and gonads reached a threshold, which suggested that the growth of those fishes was likely inhibited in Hg polluted environment.

Le comportement des thons tropicaux autour des objets flottants : De l'étude des comportements individuels et collectifs à l'étude du piège écologiqueLes recherches en halieutique ont pour objectif d'améliorer les connaissances sur le fonctionnement des populations de poissons afin de transférer celle-ci vers des outils de gestion. Ce travail de thèse repose sur un ensemble d'expériences et de modélisations destinées à approfondir notre compréhension générale du comportement associatif de poissons grands pélagiques avec des objets flottantes à la surface de l'océan. Notre objectif est de tester si les milliers d'objets flottants artificiels déployés par les pêcheurs (DCP - Dispositifs de Concentration de Poissons) constituent des pièges écologiques pour les thons tropicaux. Pour mener à bien ce travail, nous avons dans le premier chapitre caractérisé le comportement individuel de thons dans un réseau de DCP ancrés. L'analyse de données de marquage acoustique de 96 thons albacores (Thunnus albacares) (30-96 cm) à Hawaii montre que les thons présentent une plasticité comportementale forte face aux DCP qu'ils rencontrent mais également que le temps de résidence sous les DCP diminue avec la taille des individus. Afin de quantifier l'impact de l'augmentation de la densité de DCP il est essentiel de comprendre les mécanismes et les facteurs qui influencent les temps de résidences sous les DCP. Dans le second chapitre, des expériences de choix binaires suggèrent un rôle de la biomasse agrégée dans la formation, la maintenance et la dispersion des agrégations que forment les thons sous les objets flottants. La quantification de la dynamique des arrivées et des départs des poissons aux DCP permettra de valider les hypothèses que nous proposons concernant les mécanismes sociaux sous-jacents d'une part et d'autre part de tester l'influence de la qualité de l'environnement et de la densité de DCP sur les temps de résidences individuels et la distribution spatiale des populations. Dans le troisième chapitre, la comparaison de facteurs de condition de listaos (Katsuwonus pelamis) matures capturés en bancs libres et sous objets flottants dans une zone naturellement riche en objets flottants, et relativement peu impactée par le déploiement de DCP (Le Canal du Mozambique), nous a permis d'établir un point de référence essentiel pour estimer les effets des perturbations actuelles. Plus généralement, les résultats obtenus dans les différents chapitres tendent à conforter l'hypothèse d'un rôle social et non trophique des objets flottants dans l'écologie de thonidés. Les résultats obtenus durant cette thèse amènent à poser un regard nouveau sur l'hypothèse du piège écologique. Notre travail s'est principalement intéressé à un modèle biologique de choix, les thons tropicaux. Cependant le cadre théorique des questions abordées, les outils d'observations et les méthodes d'analyses développées sont assez génériques pour être appliqués aux autres espèces rencontrées sous les objets flottants. Cette recherche s'intègre plus généralement dans les problématiques visant à mieux comprendre les stratégies comportementales et la distribution des populations dans des environnements multi-sites. / Research in fisheries science aims at investigating the functioning of fish population with the objective of using this knowledge to propose sustainable management measures. This PhD thesis relies on a collection of experiments and modelling designed to further our knowledge on the aggregative behaviour of large pelagic fish with floating structures at the surface of the ocean. The overall objective is to test whether the thousands of man-made floating structures deployed by fishermen (also referred as Fish Aggregating Device –FAD) act as ecological traps for tropical tunas. To archive this main objective, it was first necessary to characterize the individual behaviour of tuna in a network of FAD. In the first chapter, the analysis of 96 acoustically tagged yellowfin tuna (Thunnus albacares) between 30-96 cm FL in the array of anchored FADs around Oahu (Hawaii, US) shows that individuals tuna exhibited behavioural plasticity while in the array and that behaviour around FAD is size dependent. In order to assess the impact of the increasing density of FAD, the major habitat modification, it is essential to understand the factors that influence the residence time at FADs. In the second chapter, binary choice experiments suggest that the aggregated biomass under the FAD play a role in the aggregative process. Nonetheless, quantification of arrival and departure dynamics of fish to FAD are required to validate the assumptions we proposed on the underlying social mechanism. Such model would, then, allow testing the effect of FAD density and environmental conditions on individual residence time and spatial distribution of population. In the third chapter, the comparison of skipjack tuna (Katsuwonus pelamis) condition between individual associated with logs and in free swimming schools in the Mozambique Channel, an area known to be naturally enriched with logs with few FADs, highlights the need for estimating reference points prior to assessing the impacts of anthropogenic modifications to habitats on animals.Combining the different chapters, our results tend to favour a social rather than a trophic role of floating objects in the ecology of tunas. More generally, we discuss what novel insight our results bring up on the ecological trap hypothesis. Tropical tunas represent an interesting model species on which we focused. However, the theoretical framework of the questions we addressed, the observation and analytical tools we developed are generic enough to be applied to the others species that are encountered around floating structures. In a broader extent, this work meets the general topic of studying behavioural strategies and distribution of population in multi-patch environment.

Made available in DSpace on 2016-06-02T19:32:09Z (GMT). No. of bitstreams: 1 5884.pdf: 1894395 bytes, checksum: 2133839c319e8789b185c3b67f243db9 (MD5) Previous issue date: 2014-06-10 / Financiadora de Estudos e Projetos / The analyses of the relative condition factor in fish community and of the benthic macroinvertebrates communities structure were used as a tool for assessing the influence of disturbances and water quality in the tropical streams of the upper portion of Monjolinho River basin, São Carlos, SP, Brazil. The condition factor revealed different responses of the fish species regarding the organic pollution effect. Astyanax cf paranae was found to be a sensitive species, Phalloceros harpagos to be tolerant, and Poecilia reticulate to be resistant. The analysis of the benthic macroinvertebrate community structure showed that these populations are affected by the loss of environmental quality, resulting in great differences in species diversity, with the absence of groups considered sensitive to pollution and dominance of resistant groups. In this portion of the Monjolinho River basin it was possible to identify streams with high environmental integrity as the Espraiado stream, up to strongly polluted streams as the Belvedere stream. / O fator de condição relativo em peixes e a análise da estrutura da comunidade de macroinvertebrados bentônicos foram utilizados como ferramenta de avaliação de distúrbios nos córregos afluentes da porção superior da bacia do rio Monjolinho, São Carlos, SP, Brasil. O uso do fator condição relativo dos peixes evidenciou diferentes respostas desses organismos à poluição orgânica, tendo a espécie Astyanax cf paranae sido sensível; a espécie Phalloceros harpagos, tolerante e a espécie Poecilia reticulata, resistente. Já a análise da estrutura da comunidade de macroinvertebrados bentônicos evidenciou que essas populações são afetadas pela perda da qualidade ambiental, resultando, em geral, menor diversidade e ausência de grupos considerados sensíveis à poluição e dominância de grupos resistentes. Nessa porção da bacia do Rio Monjolinho foram identificados desde córregos com alta integridade ambiental, como o córrego do Espraiado, até córregos fortemente poluídos, como o Belvedere.

Considering the response of organisms to their environment is difficult; it is made more so if population numbers cannot be closely monitored. In such cases different methods of population assessment are required. This thesis uses lipids as a measure of Atlantic salmon (Salmo salar L.) quality and investigates its usefulness in indicating fish condition. The first study examines the relationship between fish total lipid content and W[sub]R condition factor; this study clearly demonstrates that there is a significant positive relationship between the condition factor of a fish and its total lipid content. In the following study the lipid storage between the different tissues of the Atlantic salmon is considered. This indicates that the red muscle and the adipose tissues hold higher concentrations of lipid than the white muscle. However, the white muscle makes up the majority of lipid tissue mass in the Atlantic salmon so contains the bulk of stored lipid in a fish, at low concentration. The next study investigates the effect of spawning on Atlantic salmon condition. Salmon can be seen preferentially conserving lipid in their musculature and drawing down the lipid stored in their adipose tissues. The following study looked at one key lipid group, triacylglycerides, in salmon. Triacylglycerides are energetically important in fish and this study found that the spawning process depleted triacylglyceride reserves, but that the red muscle conserves triacylglycerides even after spawning. The final study considers the relationship between maternal quality and egg quality, identifying that longer Atlantic salmon produce eggs with more lipid after spawning migration. Egg lipid concentrations were comparably maintained between fish. Monitoring quality in this way is a useful tool to determine population wellbeing and help indicate where populations are compromised.

Made available in DSpace on 2017-07-10T18:13:16Z (GMT). No. of bitstreams: 1 Cesar Sary.pdf: 3688872 bytes, checksum: 62fe86e68d9974f69c34da4ecb6cfbd8 (MD5) Previous issue date: 2014-02-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aim of this study was to verify the oocyte and testicular development of two species Rhamdia voulezi and Steindachneridion melanodermatum. For R. voulezi, 500 fish with four months old and average weight of 11.70 g were stocked in cages (TR) and collected monthly, for S. melanodermatum, 170 fish with four years old and average weight of 799.06 g were distributed into two cropping systems, pond (VE) and TR, and collected bimonthly. The collected animals were euthanized, weighed, measured and gonads evaluated macro and microscopically. We calculated the gonadosomatic (GSI) and hepatosomatic index, abdominal fat and condition factor &#916;K. The gonads fixed in Bouin solution were dehydrated, diaphanized and embedded in paraplast. The sections of 5&#956;m, stained by technique HE. In both species, gonads are pairs structures located dorsally in region of the abdominal cavity and fused in posterior extremity forming the oviduct and sperm duct. In R. voulezi, the ovarian development was classified in phases such as immature, development (initial, intermediate and final), capable to spawning and regression, and testicular development in phases such as immature, development, capable to release sperm and regeneration, with females in the capable spawning phase in the months from December to March, period with the highest values of IGS and &#916;K. For S. melanodermatum, females and males collected in VE showed the highest values of weight and total length on collection period (p<0.05), however it was not verified macro and microscopic difference in the ovaries and testicles of animals on VE or TR, being determined four phases for gonadal development (immature, developing, capable spawning/release sperm and regeneration). Females and males of S. melanodermatum capable to spawning were collected from October to December, period with the highest values of IGS and &#916;K. In testicle of S. melanodermatum was evidenced ovarian follicles in primary growth. / O objetivo do presente estudo foi verificar o desenvolvimento ovocitário e testicular de duas espécies, Rhamdia voulezi e Steindachneridion melanodermatum. Para R. voulezi, 500 peixes com quatro meses e peso médio de 11,70g foram estocados em tanque-rede (TR) e coletados mensalmente, para S. melanodermatum,170 peixes com quatro anos e peso médio de 799,06g foram distribuídos em dois sistemas de cultivo, viveiro escavado de terra (VE) e TR, e bimestralmente coletados. Os animais coletados foram eutanasiados, pesados, medidos e as gônadas avaliadas macro e microscópicamente. Foram calculados os índices gonadossomático (IGS), hepatossomático, gordura celomática e fator de condição &#8710;K. As gônadas fixadas em solução de Bouin foram desidratadas, diafanizadas e emblocadas em paraplast. Os cortes de 5&#956;m, corados pela técnica HE. Em ambas as espécies as gônadas são estruturas pares, localizadas dorsalmente na região da cavidade abdominal e fundidas na extremidade posterior formando o oviduto e ducto espermático. Em R. voulezi o desenvolvimento ovariano foi classificado nas fases imaturo, desenvolvimento (inicial, intermediária e final), apto a desova e regressão e desenvolvimento testicular nas fases imaturo, desenvolvimento, apto a liberar esperma e regeneração, com fêmeas em fase apta a desova nos meses de dezembro a março, período com os maiores valores do IGS e &#8710;K. Para S. melanodermatum , fêmeas e machos coletados em VE apresentaram os maiores valores de peso e comprimento total médio no período de coleta (p<0,05), no entanto não foi verificado diferença macro e microscópica nos ovários e testículos dos animais mantidos em VE ou TR, sendo determinadas quatro fases de desenvolvimento gonadal (imaturo, desenvolvimento, apto a desova/liberar esperma e regeneração). Fêmeas e machos de S. melanodermatum aptos à desova foram coletados nos meses de outubro e dezembro, período com os maiores valores do IGS e &#916;K. Em testículos de S. melanodermatum evidenciou-se a presença de folículos ovarianos em crescimento primário.

Thesis (M. Sc. (Zoology)) -- University of Limpopo, 2015 / The unprecedented expansion in human population and industry, since the industrial revolution in the late 1700s, has led to increased anthropogenic activities which have indisputably impacted freshwater ecosystems and biological communities therein, including fish. Although this has understandably been the focus, under natural aquatic conditions, no organism is only affected by pollution. Parasites have also been shown in a number of interdisciplinary studies to affect the health of aquatic hosts (amphibians, crustaceans, fish, and mammals). This is illustrated in a number of comprehensive studies the detrimental effects parasites exacerbate when their hosts (fish) are stressed. Therefore, the ability of parasites to interact with anthropogenic stressors, as well as effects they have on the genetic, cellular or tissue level of their host is crucial in conservation and sustaining aquatic biodiversity. As such, the present study examined the combined effects of pollution and metazoan parasites on the health and oxidative stress biomarkers, evaluated for the first time for silver carp, Hypophthalmichthys molitrix (Valenciennes, 1844) and rednose mudfish, Labeo rosae Steindachner, 1894, in one of South Africa’s impacted freshwater ecosystems, Flag Boshielo Dam, Olifants River System, Limpopo Province. Seasonal surveys were conducted from February 2012–January 2013. A total of 111 H. molitrix and 116 L. rosae fish specimens were collected using conventional angling gear, scoop and gill nets with stretched mesh sizes of 30–110 mm. The two selected cyprinid fish species were assessed for oxidative stress biomarkers [Glutathione S-transferase (GST), lipid peroxidation (MDA) and Total Antioxidant Capacity (TAC)] and parasitism of metazoan parasites. Concentrations of biomarkers of oxidative damage and antioxidant defense in the gill and liver tissue were measured to assess how these major organs of the immune system responded to oxidative stress associated with parasitic infections. In addition, water quality analyses were carried out by testing an assay of physico-chemical parameters to establish the level of contamination. Fish health was assessed using the Health Assessment Index (HAI), refined Parasite Index (PI), Inverted Parasite Index (IPI) and Condition Factor (K) protocols. Relative to previous studies at Flag Boshielo Dam, water quality results showed an increase of nutrients, major ions and several metals which may have adverse effects that may comprise fish health; however, this dam remains moderately polluted in a mesotrophic state. The fish health assessment results indicated that H. molitrix was more affected in terms of the necropsy and parasite based assessments (HAI, IPI and K) with mean±SD of 65.68±35.51; 68.29±25; 0.82±0.20, respectively, as compared to 39.14±22.44; 28.79±18.33; 1.17±0.21 for L. rosae during the study. In addition, significantly higher parasitic infections (mean prevalence of infection with any species of parasite = 45.3±0.13) were observed for H. molitrix than L. rosae (12.0±0.05). Furthermore, there was considerable variation in biomarker concentration between highly infected and non-infected fish, for and between each species and tissues with regard to parasite infection, suggesting that the specific functions of each tissue are associated with their susceptibility to oxidative stress, as well as their ability to defend against oxidative damage. These results illustrate that although fish are affected by aquatic contaminants they are to an extent affected by parasites, which may act synergistically on the health of the two fish species. Most importantly, it was suggested that knowledge on the parasites of alien H. molitrix when compared to indigenous L. rosae may give an indication of how adaptive this fish are to new localities as well as expands the information on the rarely studied biology, epizootiology and ecological interactions of these two cyprinid species. Keywords: Health Assessment Index, refined Parasite Index, Inverted Parasite Index, Condition Factor, water quality, lipid peroxidation, Glutathione S-transferase, Total Antioxidant Capacity, Hypophthalmichthys molitrix, Labeo rosae, Flag Boshielo Dam.