A reprodução representa um dos aspectos mais importantes da biologia de uma espécie e a manutenção de populações viáveis dependem do seu sucesso. O sucesso alcançado pelos peixes em ambientes distintos deve-se à enorme gama de estratégias reprodutivas desenvolvidas pelo grupo. Nos ambientes aquáticos, a expressão da estratégia reprodutiva de uma espécie depende das interações entre fatores intrínsecos (fisiológicos, genéticos), e fatores extrínsecos como a qualidade do habitat, relações interespecíficas e também fatores físicos e regime de hidrológico. A teoria do “habitat template” propõe que a variabilidade temporal e espacial do habitat físico influencia na evolução da combinação do comportamento, fisiologia e características de história de vida das espécies. O habitat é o modelo contra o qual as pressões evolutivas dão forma à estratégia ecológica de uma espécie. Em contrapartida, as características históricas e filogenéticas limitariam algumas características específicas, independente do habitat. A teoria da história de vida lida com restrições entre variáveis demográficas e características associadas com reprodução e a maneira em que essas limitações, ou trade-offs, moldam as estratégias para lidar com diferentes tipos de ambiente. Sendo assim, o investimento em um atributo causaria a redução dos recursos disponíveis para investimento em outro. Trabalhos procurando vinculares os atributos biológicas de peixes as características ambientais do habitat em peixes propõem a existência de um gradiente entre três estratégias de história de vida em peixes de água doce: a oportunista, a de equilíbrio e a periódica. Contudo, é observado que espécies intimamente aparentadas podem exibir estratégias de história de vida diferentes ao passo que espécies distantes filogeneticamente podem convergir independentemente para estratégias semelhantes. Dentro deste contexto, o objetivo dessa dissertação é a abordagem das relações das estratégias de história de vida em relação à diferentes tipos de habitat em algumas espécies de peixes neotropicais. O primeiro capítulo trata das estratégias reprodutivas de espécies de Characidae em escala local com diferentes distribuições dentro de uma sub-bacia. Seria esperado encontrar diferenças nas estratégias reprodutivas das espécies que habitam ambientes que contrastam na magnitude das flutuações, com espécies de estratégia oportunista presentes a montante na bacia e espécies com estratégia periódica a jusante na bacia. O segundo capítulo analisa, em maior escala, as relações entre as estratégias de história de vida de peixes neotropicais da América do Sul e quatro tipos de habitat e a influência da taxonomia baseada em atributos morfológicos e reprodutivos das espécies. Se as características funcionais (um conjunto de atributos) dos organismos são previsíveis a partir características ambientais então seria esperado encontrar uma convergência desses atributos em organismos habitando o mesmo ambiente. Esse tipo de estudo é importante na busca de padrões de distribuição e na compreensão de quais características fisiológicas permitem as espécies permanecerem em um determinado ambiente ou que colonizem um novo. Esse conhecimento também é importante no manejo da pesca e na conservação dos estoques de peixes e espécies ameaçadas. A utilização de atributos funcionais permite a comparação entre áreas distantes geograficamente e entre espécies filogeneticamente distantes e auxilia na busca de padrões evolutivos. Os resultados sugerem a conservação de alguns atributos dentro de grupos taxonômicos menores, sendo possível observar uma maior afinidade de algumas famílias com alguma das estratégias de história de vida. Também é possível perceber que existe um continuum de espécies entre as estratégias, mostrando que alguns atributos são mais versáteis que outros e podem sofrer maior variação entre populações do que entre espécies. Quando se leva em consideração a diversidade de espécies de peixes neotropicais, ainda são poucos os estudos sobre informações básicas da biologia desses organismos, sendo que maior a representatividade dos estudos concentra-se em alguns grupos taxonômicos. As descrições parciais e a caracterização de forma imprecisa das características reprodutivas entre os trabalhos dificultam a sua utilização em futuros estudos. / Reproduction represents one of the most important aspects of species biology, because the maintenance of viable populations depends on its success. The success achieved by fishes in different environments is partially related to the diverse reproductive strategies developed by this group. In aquatic environments, the expression of the reproductive strategy of a species depends upon the interactions between intrinsic factors (physiological) and extrinsic factors such as the habitat quality, interspecific relationships, physical factors and hydrological regime. The habitat template theory proposes that the temporal and spatial variability of the physical habitat influences evolution of the combination of behavior, physiology and life history characteristics of species. The habitat is the model against which the evolutionary pressures shape the ecological strategy of a species. In contrast, historical and phylogenetic traits limit some specific characteristics regardless of habitat type. Life-history theory deals with constraints among demographic variables and traits associated with reproduction and the way these constraints, or trade-offs, (i.e., investments in one trait leaving fewer resources available for investment in another), shape strategies for dealing with different kinds of environments. Studies seeking to link biological traits of fishes to environmental characteristics of habitat suggest the existence of a gradient between three primary strategies in freshwater fishes: opportunistic, equilibrium and periodic. However, it has been observed that closely related species exhibit different life-history strategies, while phylogenetically distant species converge independently to similar strategies. Within this context, the goal of this study is to address the relationship in life-history strategies of Neotropical freshwater fishes against different types of habitat. The first chapter deals with the reproductive strategies of Characidae species with different distributions within the basin at a local scale. The second chapter examines at a larger scale the relationships between life history strategies of neotropical fishes of South America and four habitat types and the influence of taxonomy based on morphological and reproductive traits of the species. If the functional characteristics (a set of traits) of organisms are predictable from environmental characteristics would be expected a convergence of these traits in organisms inhabiting the same environment. The second chapter analyses the relationships among life-history strategies of Neotropical fish at different types of habitat and the taxonomic influence using a trait-based approach across large spatial scale. This type of study is important in the search for patterns in distribution and understanding which characteristics allows species to remain in a particular environment or in the colonization of a new one. This knowledge is also important in fisheries management and stocks conservation and endangered species. The trait-based approach allows comparison among geographically distant areas and phylogenetically distant species and support research in evolutionary patterns. The results suggest conservation of some attributes within lower taxonomic groups and it is possible to observe a greater affinity with some families and life-history strategies. It is possible to notice that there is a continuum of species among the strategies showing that some attributes are more versatile than others and may experience greater variation between populations than between species. Taking into account the diversity of neotropical fish species, there are few studies on basic information about the biology of these organisms and the representativeness of the studies focus on a few taxonomic groups. The partial descriptions and imprecisely characterization of reproductive characteristics among studies difficult their use in future studies.

Historical biogeography of cichlid fishes within the Usumacinta province (Mexico, Guatemala, and Belize) is reviewed based on newly collected material specifically for this study. Five areas of endemism within the province were recognized using Parsimony analysis of endemicity. Dispersal-Vicariance analysis implemented in S-DIVA suggests only one of them (the Grijalva-Usumacinta) as the ancestral area for the whole fauna. Other areas of endemism within the Usumacinta province were colonized from this area by dispersals. This biogeographic interpretation suggests a long evolution of the richest cichlid fauna in Middle America in the Grijalva-Usumacinta area of endemism in a sympatric context.

A tribo Glandulocaudini inclui os gêneros Lophiobrycon, Glandulocauda e Mimagoniates e dez espécies, distribuídas em ambientes de água doce do leste e sul do Brasil, no Paraguai e nordeste do Uruguai. São peixes neotropicais de pequeno porte, cujo grau de especialização morfológica e comportamental, bem como os padrões de distribuição das espécies, constituem interessante modelo para estudos evolutivos e para o entendimento de padrões biogeográficos de peixes de água doce na América do Sul. Embora os trabalhos sobre sistemática e biogeografia realizados recentemente representem avanço considerável no conhecimento de Glandulocaudini, nenhum foi embasado fundamentalmente em evidências moleculares. Além disso, amostragens recentes revelaram aspectos inéditos relativos à distribuição de populações alopátricas das espécies Glandulocauda melanopleura e Mimagoniates microlepis e estes novos dados indicaram a necessidade de estudos mais aprofundados em nível populacional, envolvendo a análise combinada de dados moleculares e morfológicos. A presente tese aborda estas questões, e para isto está dividida em três capítulos. No primeiro capítulo foi realizada uma análise filogenética com base em sequências gênicas do mtDNA e nuDNA para a tribo Glandulocaudini, que representa a primeira hipótese de relações proposta com base em dados moleculares para o grupo. No segundo e o terceiro capítulos foram realizadas análises filogenéticas, filogeográficas, de demografia histórica, e análises morfológicas das populações alopátricas de Mimagoniates microlepis e Glandulocauda melanopleura, respectivamente. / The tribe Glandulocaudini comprises three genera, Lophiobrycon, Glandulocauda and Mimagoniates, and ten species, distributed in freshwater environments of eastern and southern Brazil, Paraguay, and northeastern Uruguay. Its members include small Neotropical fishes, whose degree of morphological and behavioral specialization, as well as the distributional patterns of the species are of great value for evolutionary studies and understanding of biogeographical patterns of South American freshwater fishes. Although studies on systematics and biogeography carried out recently represent considerable progress on the knowledge of Glandulocaudini, none was grounded in molecular evidence. Furthermore, recent samples revealed unknown aspects concerning the allopatric distributions of populations of Glandulocauda melanopleura and Mimagoniates microlepis, and this new data indicates the need of more deep studies at population levels, combining both molecular and morphological analysis. This thesis addresses such issues and for this purpose it is divided in three chapters. In the first chapter, a phylogenetic analysis of the tribe Glandulocaudini, based on mtDNA and nuDNA data was performed, representing the first hypothesis of relationship for the group based on molecular data. In the second and third chapters, analysis of phylogeny, phylogeography and historical demography were performed, as well as morphological studies on allopatric population of Mimagoniates microlepis and Glandulocauda melanopleura, respectively.

A reprodução representa um dos aspectos mais importantes da biologia de uma espécie e a manutenção de populações viáveis dependem do seu sucesso. O sucesso alcançado pelos peixes em ambientes distintos deve-se à enorme gama de estratégias reprodutivas desenvolvidas pelo grupo. Nos ambientes aquáticos, a expressão da estratégia reprodutiva de uma espécie depende das interações entre fatores intrínsecos (fisiológicos, genéticos), e fatores extrínsecos como a qualidade do habitat, relações interespecíficas e também fatores físicos e regime de hidrológico. A teoria do “habitat template” propõe que a variabilidade temporal e espacial do habitat físico influencia na evolução da combinação do comportamento, fisiologia e características de história de vida das espécies. O habitat é o modelo contra o qual as pressões evolutivas dão forma à estratégia ecológica de uma espécie. Em contrapartida, as características históricas e filogenéticas limitariam algumas características específicas, independente do habitat. A teoria da história de vida lida com restrições entre variáveis demográficas e características associadas com reprodução e a maneira em que essas limitações, ou trade-offs, moldam as estratégias para lidar com diferentes tipos de ambiente. Sendo assim, o investimento em um atributo causaria a redução dos recursos disponíveis para investimento em outro. Trabalhos procurando vinculares os atributos biológicas de peixes as características ambientais do habitat em peixes propõem a existência de um gradiente entre três estratégias de história de vida em peixes de água doce: a oportunista, a de equilíbrio e a periódica. Contudo, é observado que espécies intimamente aparentadas podem exibir estratégias de história de vida diferentes ao passo que espécies distantes filogeneticamente podem convergir independentemente para estratégias semelhantes. Dentro deste contexto, o objetivo dessa dissertação é a abordagem das relações das estratégias de história de vida em relação à diferentes tipos de habitat em algumas espécies de peixes neotropicais. O primeiro capítulo trata das estratégias reprodutivas de espécies de Characidae em escala local com diferentes distribuições dentro de uma sub-bacia. Seria esperado encontrar diferenças nas estratégias reprodutivas das espécies que habitam ambientes que contrastam na magnitude das flutuações, com espécies de estratégia oportunista presentes a montante na bacia e espécies com estratégia periódica a jusante na bacia. O segundo capítulo analisa, em maior escala, as relações entre as estratégias de história de vida de peixes neotropicais da América do Sul e quatro tipos de habitat e a influência da taxonomia baseada em atributos morfológicos e reprodutivos das espécies. Se as características funcionais (um conjunto de atributos) dos organismos são previsíveis a partir características ambientais então seria esperado encontrar uma convergência desses atributos em organismos habitando o mesmo ambiente. Esse tipo de estudo é importante na busca de padrões de distribuição e na compreensão de quais características fisiológicas permitem as espécies permanecerem em um determinado ambiente ou que colonizem um novo. Esse conhecimento também é importante no manejo da pesca e na conservação dos estoques de peixes e espécies ameaçadas. A utilização de atributos funcionais permite a comparação entre áreas distantes geograficamente e entre espécies filogeneticamente distantes e auxilia na busca de padrões evolutivos. Os resultados sugerem a conservação de alguns atributos dentro de grupos taxonômicos menores, sendo possível observar uma maior afinidade de algumas famílias com alguma das estratégias de história de vida. Também é possível perceber que existe um continuum de espécies entre as estratégias, mostrando que alguns atributos são mais versáteis que outros e podem sofrer maior variação entre populações do que entre espécies. Quando se leva em consideração a diversidade de espécies de peixes neotropicais, ainda são poucos os estudos sobre informações básicas da biologia desses organismos, sendo que maior a representatividade dos estudos concentra-se em alguns grupos taxonômicos. As descrições parciais e a caracterização de forma imprecisa das características reprodutivas entre os trabalhos dificultam a sua utilização em futuros estudos. / Reproduction represents one of the most important aspects of species biology, because the maintenance of viable populations depends on its success. The success achieved by fishes in different environments is partially related to the diverse reproductive strategies developed by this group. In aquatic environments, the expression of the reproductive strategy of a species depends upon the interactions between intrinsic factors (physiological) and extrinsic factors such as the habitat quality, interspecific relationships, physical factors and hydrological regime. The habitat template theory proposes that the temporal and spatial variability of the physical habitat influences evolution of the combination of behavior, physiology and life history characteristics of species. The habitat is the model against which the evolutionary pressures shape the ecological strategy of a species. In contrast, historical and phylogenetic traits limit some specific characteristics regardless of habitat type. Life-history theory deals with constraints among demographic variables and traits associated with reproduction and the way these constraints, or trade-offs, (i.e., investments in one trait leaving fewer resources available for investment in another), shape strategies for dealing with different kinds of environments. Studies seeking to link biological traits of fishes to environmental characteristics of habitat suggest the existence of a gradient between three primary strategies in freshwater fishes: opportunistic, equilibrium and periodic. However, it has been observed that closely related species exhibit different life-history strategies, while phylogenetically distant species converge independently to similar strategies. Within this context, the goal of this study is to address the relationship in life-history strategies of Neotropical freshwater fishes against different types of habitat. The first chapter deals with the reproductive strategies of Characidae species with different distributions within the basin at a local scale. The second chapter examines at a larger scale the relationships between life history strategies of neotropical fishes of South America and four habitat types and the influence of taxonomy based on morphological and reproductive traits of the species. If the functional characteristics (a set of traits) of organisms are predictable from environmental characteristics would be expected a convergence of these traits in organisms inhabiting the same environment. The second chapter analyses the relationships among life-history strategies of Neotropical fish at different types of habitat and the taxonomic influence using a trait-based approach across large spatial scale. This type of study is important in the search for patterns in distribution and understanding which characteristics allows species to remain in a particular environment or in the colonization of a new one. This knowledge is also important in fisheries management and stocks conservation and endangered species. The trait-based approach allows comparison among geographically distant areas and phylogenetically distant species and support research in evolutionary patterns. The results suggest conservation of some attributes within lower taxonomic groups and it is possible to observe a greater affinity with some families and life-history strategies. It is possible to notice that there is a continuum of species among the strategies showing that some attributes are more versatile than others and may experience greater variation between populations than between species. Taking into account the diversity of neotropical fish species, there are few studies on basic information about the biology of these organisms and the representativeness of the studies focus on a few taxonomic groups. The partial descriptions and imprecisely characterization of reproductive characteristics among studies difficult their use in future studies.

A ordem Characiformes compreende cerca de 1700 espécies formalmente descritas que habitam a região Neotropical e com três famílias exclusivas da região da Etiópica subsaariana. Possui formas herbívoras, carnívoras e detritívoras, sendo uma ordem com hábitos ecológicos diversos. A classificação formal das famílias da ordem é baseada quase que estritamente em caracteres osteológicos e poucos caracteres de outras naturezas são utilizados para estabelecer hipóteses filogenéticas no grupo. Dessa maneira, o estudo do complexo morfológico encefálico preencheu essa lacuna representada pela ausência de novos caracteres de outra natureza morfológica que contribuam para o melhor entendimento das relações de parentesco entre os Characiformes. O presente estudo teve como objetivos principais a descrição e ilustração da macro morfologia encefálica de representantes das famílias de Characiformes e o levantamento de caracteres filogeneticamente informativos relacionados a esse complexo morfológico. Foram examinados 52 táxons terminais e 42 caracteres encefálicos. Adicionalmente a matriz de dados encefálicos, foram incoporados 126 caracteres osteológicos que definem os principais agrupamentos de Characiformes. O comportamento dos caracteres encefálicos foi mapeado através de uma análise de parcimônia, dessa maneira auxiliando a sustentar vários arranjos filogenéticos. Alguns arranjos filogenéticos novos foram obtidos, tais como, a relação de grupo-irmão entre Hemiodontidae + Chalceidae; Cynodontidae + Acestrorhynchidae como clado-irmão de Erythrinoidea; Gasteropelecidae + Triportheidae + Bryconidae sendo mais relacionados entre si; Crenuchidae como grupo-irmão de Characidae. Além dessas relações, corroborramos a elevação de algumas subfamílias de Characidae para o status de família, como Acestrorhynchidae, Bryconidae, Cynodontidae, Iguanodectidae e Triportheidae. A família Characidae tendo Heterocharacinae como ramo basal e sustentada principalmente por caracteres osteológicos tendo adicionalmente, um caráter exclusivo encefálico. Aphyoditeinae + Aphyocharacinae + Cheirodontinae mais relacionados e a subfamília Characinae como um grupo monofilético. / Characiformes comprises about 1.700 formally described species inhabiting the Neotropical region and three exclusives families of sub-Saharan Etiopic. The species of the order have herbivorous, carnivorous and detritivores feeding habits, being an order of several ecological habits. The formal classification of the families of the order is based almost exclusively on osteological characters and very few of characters of other types are used to establish phylogenetic hypotheses in the group. Thus, the present study of brain morphological complex aims to fill this gap represented by the absence of new morphological characters of another nature that might contribute to a better understanding of the relationships among the Characiformes. Thus, the present study had as main objectives the description and illustration of external brain morphology of representatives of all the families of Characiformes and the searching for phylogenetically informative encephalic morphological characters. For this, 52 terminal taxa and 42 brain characters were examined, in addition of brain data set, have been examined 126 osteological characters that define the main groups of Characiformes. The behavior of brain characters was mapped through a parsimony analysis, thus helping to sustain several phylogenetic arrangements of Characiformes. Some new phylogenetic arrangements were obtained, such as: the sister-group relationship between Hemiodontidae + Chalceidae; Cynodontidae + Acestrorhynchidae as clade-sisters of Erythrinoidea; Gasteropelecidae + Triportheidae + Bryconidae forming a monophyletic group; Crenuchidae as sister group of Characidae. In addition to these relationships, we corroboratethe elevation of some subfamilies of Characidae to family status, such as Acestrorhynchidae, Bryconidae, Cynodontidae, Iguanodectidae and Triportheidae. The Characidae family having Heterocharacinae as the most basal clade and sustained mainly by osteological characters, plus an exclusive character of brain nature. Aphyoditeinae + Aphyocharacinae related to Cheirodontinae and, Characinae subfamily as a monophyletic group.

M.Sc. / The Olifants- and Luvuvhu rivers both flow through the Kruger National Park (KNP). The Olifants River (OR) is a major tributary of the Limpopo River with water quality being less than desirable due to high concentrations of pollutants as a result of the activities in the upper catchment. The crocodile population of the river declined from 1000 in 2008 to 347 in 2009 due to pansteatitis. Labeobarbus marequensis in the upper catchment also showed symptoms of the disease (Templehoff, 2010). This raised concern about the health of the fish in the OR, particularly in the section flowing through the KNP. The Luvuvhu River (LR) is also a tributary of the Limpopo River with main land uses in the catchment being agriculture, mining and communal lands. Of concern is the finding of DDT residues in water, sediment, and domestic and indigenous biota upstream of the sites sampled in this study (Barnhoorn et al., 2009) which raised concerns about the health of fish in the lower reaches of the river flowing through the KNP. Therefore, the aim of this study was to assess the health status of [9] selected fish species from the OR and LR in the KNP using a histology-based health assessment protocol (HBHA). The species selected for this study included Hydrocynus vittatus, Labeobarbus marequensis, Labeo cylindricus and Labeo rosae. The OR was sampled in September 2009 and May 2010 while the LR was sampled in November 2009 and April 2010. A necropsy was done to determine if there were any internal or external macroscopic alterations with any alterations noted on a score sheet. Blood was taken for haematocrit (Hct), leukocrit (Lct) and total plasma protein (TP) determination. As part of the HBHA, a necropsy-based health assessment index (HAI) was applied using a modified protocol of Adams et al. (1993) where the necropsy and blood parameters were used to calculate the mean and sum HAI for the different species sampled on each sampling trip. Biometric indices including the condition factor, hepatosomatic index, splenosomatic index and the gonadosomatic index were calculated. Age was determined using otoliths for tigerfish and scales for the other species. Samples of selected organs (liver, kidney, gill, testes or ovaries) were taken for histological analysis. Microscope slides were assessed qualitatively to identify any histological alterations present. These results were semi-quantitatively assessed according to the protocol of Van Dyk et al. (2009a) from which an organ index and fish index were calculated. The organ index is an indication of the number and severity of histological alterations in a particular organ of a selected species. The organ indices were classed according to the classes of Van Dyk et al. (2009a) with Class 1 (<10) being tissue with slight histological alterations; Class 2 (10-25) being tissue with moderate histological alterations. The fish index is a sum of all of the organ indices for any given fish sampled.

M.Sc. (Zoology) / Temperature plays a very important role in the metabolic environment of coldblooded animals such as fish. The primary objective of this study was to evaluate the quality of digestive processes and the importance of temperature in the digestive system of Labeo capensis. An important consideration in the choice of the experimental animal was the economic potential and widespread occurrence of Labeo capensis in the riversystems of the Transvaal. The experimental animals were kept at three different acclimation temperatures ( 14, 19 and 25 + 1°C) for a period of six weeks. An assessment of the influence of acclimation temperature on enzyme activity vas made using test kits supplied by BOERINGER-MANNHEIM. No information exists on the morphohistology of Labeo capensis and therefore investigation on the anatomy of the digestive system was carried out in this survey. The ventro-anterior mouth is ideally situated for bottom-feeding. Pharyngeal teeth and a pharyngeal pad (or palatal organ) is situated dorsally at the entrance to the oesophagus. A short oesophagus, which possesses both a supra- and infraoesophageal valve, exists. No stomach is present and the intestinal bulge affixes the intestine to the oesophagus. The exceptionally Iona intestinum proper lies coiled in the abdominal cavity. No rectum can be identified. The micro-anatomy of the intestinal proper and bulge differs minimally. The intestinal bulge possesses longer, slimmer villi in comparrison of the flat thickened villi of the intestine proper. The bulge lacks a longitudinal muscle layer. L. capensis cellulase and dicarrboxylase activty may be contributed to the intestinal microflora and/or foodstuffs present in the digestive system. Amylase possesses the highest and the proteases (trypsin and chymotrypsin) the lowest activity. The effect of acclimation temperature is most evident on amylase, and to a lesser extent on the phosphatases. Trypsin and chymotrypsin activity is less affected by acclimation temperature, although a distinctive loss of activity is recorded for both these enzymes. The loss of acid phosphatase activity is partially contributed to the rise in intestinal pH. The effect of reaction temperature was measured and recorded as AT-values.

MSc. (Zoology) / The Albasini Dam was used as a reference site outside the DDT (1, 1, 1-trichloro-2, 2-bis (p-chlorophenyl) ethane) - sprayed area in a previous survey conducted from 2006 to 2008. DDT, endocrine disrupting chemicals and inorganic chemicals were detected in the dam. A histological analysis of fish from the dam showed histological alterations in heart, liver, gills, and gonads. Therefore, it was necessary to follow up the health status of the dam by monitoring the levels of organic and inorganic chemicals and their effects on fish. The aim of the present study was to determine the health status of three freshwater fish species, Clarias gariepinus, Oreochromis mossambicus, and Coptodon (Tilapia) rendalli from the Albasini Dam, using fish histology as a biomonitoring tool. In total, 18 fish were sampled using gill nets; these included Clarias gariepinus (n=5); Coptodon (Tilapia) rendalli (n=4) and Oreochromis mossambicus (n=9). The histology-based fish health assessment included a standard fish necropsy; a calculation of blood parameters (haematocrit, leukocrit and total plasma protein); somatic indices and the condition factor and a qualitative and semi-quantitative histological assessment of five target organs: liver, heart, gills, kidney and gonads. Water, sediment and fish muscles samples were collected and analysed for inorganic chemicals and organic chemicals. Inorganic chemicals were analysed by means of Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optic Emission Spectrometry (ICP-OES). Organic chemicals in water and fish muscles were analysed using Gas Chromatography-Mass Spectrometry (GC-MS). Nutrients and physical parameters of water were also measured...

The use of intestinal parasites as indicators of pollution has increased in Europe due to the fact that parasites accumulate more of the available metals than their hosts. Eighty Largemouth yellowfish, Labeobarbus kimberleyensis (Gilchrist and Thompson, 1913) were collected between April 2005 and February 2006 with gill nets at RAU Island (26° 52, 249’ S, 28 10, 249’ E) in the Vaal Dam. The fish were killed, weighed and their lengths determined. Muscle, liver and spinal cord tissues were collected from each fish and the intestines removed and opened to expose Bothriocephalus acheilognathi. The position of attachment of B. acheilognathi in the host’s intestine was recorded. Thereafter tapeworms were collected in glass bottles and frozen. Water and sediment samples were collected. Clossed vessel microwave digestion was used to digest liver, muscle and tapeworms with Suprapur Nitric acid, and spinal cord tissue with Suprapur Nitric acid and Suprapur Hydrochloric acid. Thereafter metal concentrations of twenty three elements (Lithium, Beryllium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Arsenic, Selenium, Molybdenum, Cadmium, Tin, Antimony, Tellurium, Barium, Mercury, Thallium, Lead and Uranium) were determined specifically for each tissue type with an ICP-MS. Certified dogfish liver (Dolt-3) was used as a quality control standard. Water quality data was provided by Rand Water and included. Statistical data were analyzed with ANOVA and post-hoc tests and parasite infection statistics were calculated. Seasonality and intensity of tapeworms were compared to the intestine and total lengths of the fish. All the tapeworms were identified as the Asian Tapeworm B. acheilognathi Yamaguti, 1934. Bothriocephalus acheilognathi attached between 10% and 20% from the anterior end of host intestine. A 100% prevalence of Asian tapeworm was recorded in all surveys and the highest mean intensity of 231.1 was recorded in autumn and the lowest mean intensity of 73.7 was recorded in summer. The fecundity of largemouth yellowfish was not influenced by the high infection rate of B. acheilognathi as young fish fry was collected during the summer survey and the fish condition was good. No correlation was observed between parasite intensity and total length of each fish. This indicates that intensity is not dependant on host size. Parasite numbers are higher and differ from a previous study. Water quality of Vaal Dam changed in summer, due to transferance of water from the Grootdraai Dam. Algal counts and secchi disk readings increased. This indicates that zooplanktonic intermediate hosts increased due to an increase in food availability and increased the chance of infection. Significant differences were recorded in one sample T-test comparisons, while ANOVA indicated that significant differences between tissue groups and seasons occurred. Bioaccumulation of metals occurred in tapeworms in Selenium, Mercury, and Lead during autumn, Copper, Zinc, Selenium, Cadmium, Antimony, Thallium and Mercury during winter, Lithium, Zinc, Selenium, Cadmium and Antimony during spring and Zinc during summer. The highest mean value was recorded in sediment, followed by water, tapeworms and then the host tissue. The general trend was sediment > water > tapeworms > liver > spinal cord > muscle. Die gebruik van intestinale parasiete as indikatore vir besoedeling het in Europa verhoog omdat die parasiete meer van die beskikbare metale as hul gashere akkumuleer. Tagtig Grootbekgeelvisse Labeobarbus kimberleyensis (Gilchrist en Thompson, 1913) was tussen April 2005 en Februarie 2006 met kieunette te RAU eiland (26° 52, 249’ S, 28 10, 249’ E) in die Vaaldam versamel. Die visse is doodgemaak, geweeg en hul lengtes bepaal. Spier, lewer en werwelkolomweefsel was versamel van elke vis en die intestinums verwyder en oopgemaak om Bothriocephalus acheilognathi bloot te lê. Die posisie van aanhegting van B. acheilognathi in die gasheer se intestinum is aangeteken. Daarna is die lintwurms in glasbottels versamel en gevries. Water en sediment was ook versamel. Geslote-flesmikrogolfvertering was gebruik om lewer, spier en lintwurms met Suprapur® Swaelsuur en werwelkolom met Suprapur® Swaelsuur en Suprapur® Soutsuur te verteer. Daarna is die metaalkonsentrasies van drie-en twintig elemente (Litium, Berillium, Titanium, Vanadium, Chroom, Mangaan, Yster, Kobalt, Nikkel, Kopper, Sink, Arseen, Selenium, Molibdenum, Cadmium, Tin, Antimoon, Tellurium, Barium, Kwik, Tallium, Lood and Uranium) spesifiek vir elke weefseltipe bepaal met ‘n IGP-MS. Gesertifiseerde haailewer (Dolt-3) was gebruik as ‘n standaard ter wille van kwaliteitskontrole. Waterkwaliteitsdata is deur Rand Water verskaf en word ingesluit. Statistiese data was geanaliseer met ANOVA en nagraadse toetse en parasiet infeksie statistieke was bereken. Seisonaliteit en intensiteit van die lintwurms was vergelyk met die totale lengtes van visse en intestinumlengte van die visse. Al die lintwurms was as Asiese lintwurms B. acheilognathi Yamaguti, 1934 geïdentifiseer. Bothriocephalus acheilognathi was tussen 10% en 20% vanaf die anteriorgedeelte van die gasheerintestinum geheg. ‘n 100% persentasiebesmetting was opgeteken in alle opnames met Asiese lintwurms en die hoogste gemiddelde besmettingsintensiteit van 231.1 was opgeteken in die herfs en laagste gemiddelde besmettingsintensiteit van 73.7 waargeneem in die somer. Die broeisukses van die Grootbekgeelvisse was nie beïnvloed deur die hoë infeksies met B. acheilognathi nie, soos blyk uit die feit dat jong vissies versamel is tydens die someropname en die viskondisie was ook goed. Daar was geen korrelasie waargeneem wanneer die parasietintensiteite en totale lengtes van die visse vergelyk is nie. Dit dui dat intensiteit nie afhanklik is van gasheergrootte nie. Die parasietgetalle is hoër en verskil van ‘n vorige studie. Die waterkwaliteit van die Vaaldam het verander gedurende somer a.g.v. die toevoer van water vanaf die Grootdraaidam. Die algtellings en die secchi-skyf lesings het dus verhoog. Dit dui dus aan dat die getal soöplanktoniese tussengashere verhoog het agv die verhoogde voedselbeskikbaarheid en ‘n hoër kans van infeksie vir visse. Betekenisvolle verskille was waargeneem wanneer enkel monster T-toets vergelykings gemaak is, terwyl ANOVA betekenisvolle verskille tussen groepe en seisoene gewys het. Bioakkumulasie van metale in lintwurms het in selenium, kwik en lood gedurende herfs, en in koper, sink, selenium, cadmium, antimoon, tallium en kwik in winter, en in litium, sink, selenium, cadmium en antimoon in lente en in sink gedurende somer voorgekom. Die hoogste gemiddelde waarde was waargeneem in sediment, gevolg deur water, lintwurms en gasheerweefsel. Die algehele akkumulasie verwantskap is sediment > water > lintwurms > lewer > werwelkolom > spier. / Prof. Annemarie Avenant-Oldewage

M.Sc. (Zoology) / Please refer to full text to view abstract