Articles by Author: A S J Barnhoorn

Search results for A S J Barnhoorn

We found 9 results for you
  1. A comparison between the diets of small and large stock on mixed karoo veld<sup>1</sup>

    A comparison between the diets of small and large stock on mixed karoo veld<sup>1</sup>

    The botanical composition of the diet of oesophageally fistualated Dorper and Merino sheep, Boer goats and Afrikaner cattle, grazing a mixed Karoo veld, was determined quarterly. The botanical composition of the diets were determined by means of a microscope point...
  2. Sublethal effects of manganese on the haematology and osmoregulation of <em>Oreochromis mossambicus</em> after acute exposure

    Sublethal effects of manganese on the haematology and osmoregulation of <em>Oreochromis mossambicus</em> after acute exposure

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    Oreochromis mossambicus were exposed for 96 hours to sublethal manganese concentrations in a continuous flow-through system. The sublethal concentrations were determined from the LC50 value of manganese (1.723mg/l), which included a 10% (172.3mg/l), 15% (259.8mg/l) and 20% (345.6mg/l) concentration of...
  3. Histopathological changes in two potential indicator fish species from a hyper-eutrophic freshwater ecosystem in South Africa: a baseline study

    Histopathological changes in two potential indicator fish species from a hyper-eutrophic freshwater ecosystem in South Africa: a baseline study

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    Histopathological changes were identified in selected target organs from two freshwater fish species, Clarias gariepinus and Oreochromis mossambicus, inhabiting the hyper-eutrophic Roodeplaat Dam near Pretoria. A histology-based fish health assessment protocol was used, including a semiquantitative histopathological assessment of the...
  4. Histological changes in the gills of <em>Clarias gariepinus</em> (Teleostei: Clariidae) from a polluted South African urban aquatic system

    Histological changes in the gills of <em>Clarias gariepinus</em> (Teleostei: Clariidae) from a polluted South African urban aquatic system

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    A semi-quantitative histological assessment was used to investigate histological changes in the gills of Clarias gariepinus from Marais Dam and Rietvlei Dam near Pretoria, which receive effluent from sewage treatment plants and industries, as well as runoff from informal settlements...
  5. Sublethal effects of manganese on the carbohydrate metabolism of <em>Oreochromis mossambicus</em> after acute and chronic exposure

    Item type: Journal Article • Journal: South African Journal of Zoology
    Carbohydrate metabolism variables of Oreochromis mossambicus were investigated after acute and chronic sublethal manganese exposure. The sublethal concentrations were determined from the LC50 value of manganese. After the exposures, the fish were carefully netted and blood was drawn from the...
  6. Extensive netting in Albasini and Nandoni dams: a potential threat to fish as a sustainable food source in the Vhembe District, South Africa

    Extensive netting in Albasini and Nandoni dams: a potential threat to fish as a sustainable food source in the Vhembe District, South Africa

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    Fish populations in Albasini and Nandoni dams are negatively affected by extensive netting practices. This observation was made by the authors following a number of fish health assessment surveys related to aquatic pollution in the Luvuvhu River catchment. A comparison...
  7. Health assessment of freshwater fish species from Albasini Dam, outside a DDT-sprayed area in Limpopo province, South Africa: a preliminary study

    Health assessment of freshwater fish species from Albasini Dam, outside a DDT-sprayed area in Limpopo province, South Africa: a preliminary study

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    During 2006 to 2008, the water, sediment and fish in Albasini Dam, used as a reference site outside a DDT-sprayed area, had been found to be as affected as those in the nearby DDT-sprayed area were. Accordingly, the aim of...
  8. Health and chemical burdens of fish species from polluted and hyper-eutrophic freshwater ecosystems in South Africa

    Health and chemical burdens of fish species from polluted and hyper-eutrophic freshwater ecosystems in South Africa

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    Three aquatic ecosystems in South Africa, the Hartbeespoort, Klipvoor and Bospoort Dams, are classified as hyper-eutrophic, because of high nutrient loads and chemical pollution. Water and two fish species, Clarias gariepinus and Cyprinus carpio, were collected from these dams to...
  9. Nevirapine in African surface waters induces liver histopathology in <em>Oreochromis mossambicus:</em> A laboratory exposure study

    Nevirapine in African surface waters induces liver histopathology in <em>Oreochromis mossambicus:</em> A laboratory exposure study

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    Nevirapine (NVP) is one of the HIV antiretrovirals detected recurrently in African surface waters. Liver side effects in humans were reported. Because the effects on fish are unknown, this study investigated the potential effects of NVP on selected biometric indices...