Academic literature on the topic 'Clarias gariepinus parasites'

The study examined helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of C.gariepinus and T. zillii) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus), Cestodes (Polyonchobothrium torulosus and P. clariae) and Trematodes (Dactylogyrus extensus and Glossiduim pedatum) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from C. gariepinus out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from T. zilli, of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P<0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, C. gariepinus had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in T. zillii. Key words: fish parasites, aquaculture, prevalence, C. gariepinus, T. zillii

Two catfish: Clarias batrachus (Linnaeus) and C. gariepinus (Burchell) were selected for examination during June, 2014 to May, 2016. The percentage (g/100 g) of nutrients such as moisture, ash, fat, protein, carbohydrate contents (mg/100 g) and energy (K cal) in C. batrachus and C. gariepinus was determined. Analyses were done to measure the nutrition value of edible body parts (flesh) of C. batrachus and C. gariepinus. The effects of modifying factors such as, season, sex, length, and diet of the hosts on the abundance of parasites were also studied. Present observation on biochemical analysis showed small variation in nutrient contents between C. batrachus and C. gariepinus. Protein, fat, moisture, carbohydrate levels were higher in non-infected C. batrachus (moisture 78.25 ± 0.06 g/100 g, ash 1.42 ± 0.09 g/100 g, fat 1.20 ± 0.04 g/100 g, protein15.05 ± 0.19 g/100 g, carbohydrate 5.53%) and non-infected C. gariepinus (moisture 78.62 ± 0.01 g/100 g, ash 1.22 ± 0.10 g/100 g, fat 1.19 ± 0.03 g/100 g, protein 14.69 ± 0.07 g/100 g, carbohydrate 4.95% than those of infected C. batrachus and C. gariepinus. In both species the highest presence of most of the nutrient components was observed in winter. Bangladesh J. Zool. 47(1): 27-39, 2019

AbstractThe factors that determine parasite assemblages among the clariid fishes of Lake Victoria, Tanzania were studied between August 2003 and February 2005. Six hundred and fifty-six fish belonging to seven species were necropsied and examined for parasites, from which 31 species of metazoan parasites were recorded. The community was dominated by the nematodes both in species and numbers. Most species were generalists with only two trematodes, Diplostomum mashonense and Tylodelphys species, being specialists of Clarias gariepinus. Ten species were considered core and predictable. Parasite species richness, number of individuals per host and Shannon–Wiener diversity indices were generally high. At the compound community level, a mean number of 7.8 parasites were shared among different species of fish and the maximum number of parasites species per fish at the infracommunity level was seven. Levels of similarity in parasite species richness at the component community level ranged from 29.6 to 61.5%. The study concludes that parasite communities in clariid fishes of Lake Victoria are structured by ecological factors. At the infracommunity level, host size, diet and vagility promoted a richer parasite community. At the compound level, two factors were crucial, namely the intermixing of the waters in the lake and the predominant and mobile C. gariepinus.

Abstract Clarias gariepinus is a fish from North of South Africa and was later introduced in several countries, including Brazil. The present study aimed to describe the first report of Diplostomidae metacercariae in C. gariepinus in Brazil. For this, 30 C. gariepinus were captured in a lake in the city of Campos dos Goytacazes, RJ, Brazil. Fishes were euthanized using freezing and necropsied for collection of parasites. The organs were dissected and analyzed for the presence of parasites that were processed for light and scanning electron microscopy. Trematodes were stained with Semichon’s Carmine and Gomori’s Trichrome, observed and schematized under a light microscope with image analysis software. A total of 190 trematodes were collected from the gills, suprabranchial organs, heart, stomach, intestinal mesentery, liver and body cavity of the fish. The parasites had a foliaceous body divided by a discrete constriction, without genital primordia, and a holdfast organ present at the posterior region, typical of metacercariae of the family Diplostomidae. It was classified as the 'Diplostomulum' morphotype, based on the morphology of the reserve bladder structure. This is the first report of the metacercariae of Diplostomidae parasitizing C. gariepinus in the Americas. This fish acts as an intermediate or paratenic host of this digenean in Brazil.

Abstract This research was aimed to find out the prevalence and degree of infection Trichodiniasis on the Dumbo catfish (Clarias gariepinus) in four ponds cultivation of Sumenep Regency, East Java. The total of 200 samples of Dumbo catfish were from four cultivation ponds to be examined in the Parasitology laboratory of the Faculty of Veterinary Medicine, Univercity Wijaya Kusuma Surabaya. The examination was carried out by means of scraping mucus as well as taking the gill Lamella and observed under the microscope with 100x and 400x magnification. The results showed that the highest level of Trichodiniasis prevalence was in the cultivation pool C (64%) With the degree of infection 5.62 individual parasites/fishes including the category of severe infections while in the pond cultivation A (28%) With the degree of infection 1.86 individual parasitic/fish, cultivation pool B (30%) With the degree of infection 2.46 individual parasites/fishes and the cultivation pond D (48%) With an infection degree 3.02 individual parasites/fishes including a category of mild infections. So using Uji-T can be known results of cases of Trichodiniasis that attacked Dumbo catfish (clarias gariepinus) on four pools of cultivation in Sumenep Regency, East Java showed a very noticeable difference.

A study on the gastro-intestinal helminth parasites of wild C. gariepinus was carried out in Gwagwalada Area Council of FCT, Abuja, Nigeria. A total of 110 samples were examined which includes 42 males and 68 females. Forty-eight (43,64%) fishes were infected with various species of helminth, which includes Wenyonia spp (28,18%), Procamallanus laevionchus (11,82%) and Euclinostomum heterostomum (3,64%). The female fish had the highest percentage prevalence (28,18%) while the males had 15,46% prevalence. Most of the parasites were recovered from the intestinal lumen. There was some degree of specificity in their distribution within the host but there was no significant difference (P>0,05) between the standard length, body weight, number of fish infected, prevalence and the intensity of infection.KEY WORDSHelminth parasites, Wild, C. gariepinus, Gastro-intestinal tract, Gwagwalada

The study of teleost parasites in an ecologically altered ecosystem through dam construction that evidently facilitate parasitic infections and aggravate public health concerns is essential. The study of stream linked dam showed that Tilapia zillii (Gervais, 1848), Pelmatolapia mariae (Boulenger, 1899) and Clarias gariepinus (Burchell, 1822) form the major fish composition of these reservoirs. They serve important food resource globally especially places bereft of extensive aquaculture practices. Although, knowledge about the gill parasites of P. mariae is inexistent the examined individual P. mariae showed that it had 54% Heterophyes heterophyes infection, C. gariepinus had no parasitic infection whereas T. zillii had a relatively very low Batrachobdelloides spp (1.7%). Besides, the highest DO levels in the dam occasioned by high agitation and floatation the physical factors conditions - pH and DO (> 6 mg.L^-1) had suitable levels for biodiversity.

Thèse en co-tutelle
Pour tester l’efficacité du traitement antiparasitaire courant en pisciculture, des élevages de Chrysichthys nigrodigitatus ont été réalisés dans le sud de la Côte d’ivoire dans des milieux écologiques différents. Pendant l’essai, l’Ovaldine® a été associé au Slice® (OS) ; le Parasiticide-S® au Pycèze® (PP) et la chaux a été utilisée seule (CH). Ces produits ont été utilisés à Jacqueville dans trois étangs différents. Quatre autres élevages ont été conduits à Layo, de Mopoyem et d’Anyama parallèlement à celui de Jacqueville où les étangs n’ont pas été traités. Au terme de cette étude, les poissons traités présentent en termes de performances zootechniques et d’indices épidémiologiques une différence significative comparativement aux poissons issus d’élevage non traités. En revanche aucune différence n’a été constatée chez les poissons non traités. Malgré ces différences de croissance de poissons imputables aux antiparasitaires, l’utilisation des produits chimiques en élevage pose non seulement des problèmes écologiques mais aussi, constitue un danger pour le pisciculteur
To test the effectiveness of current pest control treatment in fish farming, Chrysichthys nigrodigitatus have been made in the south of Ivory Coast in different environments. During the testing, Ovaldine® was associated with Slice ® (OS), the parasiticide-S® to Pyceze® (PP) and lime was used alone (CH). These products have been used to Jacqueville in three different ponds. Four other farms were taken to Layo of Anyama Mopoyem and parallel to that of Jacqueville where ponds have not been addressed. At the end of this study, the fish are treated in terms performance zootechnical and epidemiological evidence have a significant difference compared to farmed fish from untreated. Despite these differences in growth of fish due to pesticides, the use of chemicals in farming poses not only environmental problems but also constitutes a danger to the fish farmer

Orientador: Edson Aparecido Adriano
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Prochilodus lineatus, Hoplias aff. malabaricus e Clarias gariepinus, são comumente encontrados nas Bacias dos rios Grande e Mogi-Guaçu. O objetivo desse estudo é descrever a diversidade das espécies de metazoários parasitos que infectam estas três espécies de peixes coletados nos Rios Turvo e Mogi-Guaçu. As coletas foram realizadas com auxílio de redes de espera e ocorreram entre fevereiro de 2010 a junho de 2012 em três pontos de estudo: lagoa marginal do rio Turvo, no município de Nova Granada (SP); rio Mogi Guaçu (leito do rio próximo a Cachoeira de Emas e lagoas marginais), município de Pirassununga (SP). O trabalho foi dividido em três capítulos, sendo que o primeiro trata do inventário das espécies de metazoários que infectam as três espécies de peixes alvo do estudo. Os resultados mostraram que juntas, estas três espécies de peixes hospedavam 30 espécies de parasitos. Dentre os metazoários parasitos, o filo Nematoda foi o que apresentou maior riqueza de espécies. A espécie de hospedeiro que apresentou maior riqueza parasitária foi H. aff. malabaricus. Os espécimes de P. lineatus apresentaram infecção por duas espécies de monogeneas, uma de digenético e uma de acantocéfalo. Espécimes de C. gariepinus apresentaram infecção por três espécies de nematódeos e uma de acantocéfalo. O segundo capítulo envolveu o estudo taxonômico de três espécies de Monogenea do gênero Anacanthorus, sendo esta a primeira descrição de espécies deste gênero em peixes do gênero Hoplias. O terceiro capítulo trata do estudo taxonômico de uma nova espécie do gênero Vaigamus, a qual foi encontrada infectando filamento branquial de H. aff. malabaricus coletados em uma lagoa marginal do Rio Mogi-Guaçu. Este é a primeira descrição de parasito do gênero Vaigamus em peixes do gênero Hoplias, e é a terceira espécies descrita para este gênero
Abstract: The fish species Prochilodus lineatus, Hoplias aff. malabaricus and Clarias gariepinus are commonly found in the basins of the Rio Grande and Rio Mogi-Guaçu rivers. The aim of the present study was to create an inventory of species of metazoans that infect these three fish collected from the Turvo and Mogi-Guaçu River. Collections were performed with gill nets between February 2010 and June 2012 at three study points: Turvo river (an oxbow lake), in municipality of Nova Granada, São Paulo state, Brazil; Mogi Guaçu (river bed near the Cachoeira das Emas waterfall, and oxbow lakes) municipality of Pirassununga, São Paulo state, Brazil. The study was divided into three chapters. The first chapter features an inventory of the species of metazoans infecting the three fish species studied. The results show that together the three species of fish hosts 30 species of parasite. Among the metazoans, the phylum Nematoda presented the greatest richness of parasite species. The host species with the greatest parasitic richness was H. aff. malabaricus. Specimens of P. lineatus were infected by two monogenean, one digenean and one acanthocephalan species. Specimens of C. gariepinus were infected by three nematode and one acanthocephalan species. The second chapter involves the taxonomic study of three species of monogeneans of the Anacanthorus genus, the first description of species of the Anacanthorus genus in fish of the Hoplias genus. The third chapter is a taxonomic study of a new species of the Vaigamus genus, which was found infecting the gill filament of H. aff. malabaricus collected in an oxbow lake of the Mogi-Guaçu river. This is the first description of parasites of the Vaigamus genus in fish of the Hoplias genus, and is the third species identified for this genus
Doutorado
Parasitologia
Doutor em Parasitologia

Ph.D.
Female adult specimens of Lamproglena clariae attach to gill filaments of freshwater fish of the family Clariidae, penetrate the gill tissue and consume blood. Previously, studies have been done on the taxonomy of this parasite, but little research has been published on biological aspects. Hence, it was the aim of this study to determine and record L. clariae’s aspects of biology such as ecology, life cycle and pathology. The study was conducted through both field and laboratory observations with specimens collected from the Vaal Dam and Vaal River Barrage. A positive correlation was observed between the host's physical dimensions and the size of the parasite, parasites from both sites preferred the fourth gill and the median part of the gill arch for attachment. There was no significant host gender preference by parasites. Three free living nauplius stages, four copepodite, a cyclopoid and adult stages were recorded as life stages of this parasite. Observations suggested that development of larval stages of L. clariae is influenced by both photoperiod and temperatures. Furthermore low infestation success of the experimental fish was observed. This parasite caused localised infestation as varying degrees of swelling of gill filaments were observed only in the vicinity of its attachment site. Histological examination revealed epithelial hyperplasia, resulting in fusion of gill lamellae and necrosis of the host tissue in the vicinity of the parasite. No correlation exists between the infestation intensity and fish haematocrit values. Although L. clariae causes localized infestation, high intensity of infestation may be detrimental to the fish. Hyperplasia of epithelial tissue resulting in fusion of lamellae would result in restriction of oxygen passage and thus hinder the process of respiration of the host.
Prof. A. Avenant-Oldewage

The Rietvlei Dam near Pretoria, South Africa, provides drinking water for the city and for the wild life in the Rietvlei Nature Reserve, and is also used for recreational fishing. The dam is part of the Sesmyl Spruit system, which has a history of pollution, the major sources of which are industrial, agricultural and sewage from informal human settlements upstream of the reserve. With a large wetland separating the upstream Marais Dam and the Rietvlei Dam, the system has a high conservation priority status because of the high number of bird species that breed and roost in the various habitats. As part of a big aquatic health project in the Zoology Department, Rand Afrikaans University, aimed at finding suitable biomarkers for water quality monitoring in the system, this study was done to identify the major internal helminth parasites of the sharptooth catfish, Clarias gariepinus, that can be used in fish health assessment studies, and to determine their prevalence and intensity in the Rietvlei Dam. Fish were collected during one sampling survey and examined for endoparasites, also noting any ectoparasites that are recorded in routine fish health studies. Five species of helminths were identified: the adult cestodes, Polyonchobothrium clarias (intestine and stomach), Proteocephalus glanduliger (anterior intestine), the adult nematode Procamallanus laevionchus (stomach), larvae of the nematode Contracaecum sp. and many trematode metacercariae encysted in the muscles, of which only Ornithodiplostomum sp. was successfully excysted and identified. This trematode is recorded in South Africa for the first time, but could not be specifically identified because the reproductive system was still immature. Examination of piscivorous birds in the area or experimental infection of young birds are the only means by which the adult trematodes can be obtained. The adult cestodes and nematodes had specialised structures for attachment to the stomach and/or intestinal mucosa, adaptations associated with pathological effects in the host. Polyonchobothrium clarias had a crown of 26-30 hooks on its rostellum, and this number differs from those of specimens described from catfish in other African countries. Scanning electron microscopy showed that the rostellum of the P. clarias specimens from Rietvlei Dam was different from that of specimens from other localities in South Africa. Proteocephalus glanduliger in C. gariepinus from Rietvlei Dam differed in strobila size and size of glandular organ from specimens described by Janicki (Egypt) and Mashego (South Africa), the present specimens being much longer but with smaller glandular organs. Procamallanus laevionchus is a common parasite of catfish from many African countries, including South Africa, and scanning electron microscopy showed some form of transverse markings and presence of papillae-like structures at the posterior end of female specimens, an observation which was not described in previous studies. Larval Contracaecum are also common in C. gariepinus and other fish species, and adults have been identified in several species of fish-eating birds from South Africa. The sample size of fish collected in this survey was too low for a full health assessment index (HAI) study to be undertaken. Polyonchobothrium clarias and Contracaecum, however, were highly prevalent in the host species, and Contracaecum and Ornithodiplostomum occurred at high intensity (up to 44 and 140 respectively). Endoparasites of C. gariepinus can therefore be used in the fish HAI as a bioindicator of water quality. Only two ectoparasitic species were found on C. gariepinus: Argulus japonicus (skin and fins) and Lamproglena clariae (gills). Most water quality variables from the dam were within the target limits recommended by the Department of Water Affairs and Forestry, but the levels of inorganic nitrogen (nitrate and ammonia) and phosphorus (orthophosphate) exceeded the limit. If uncontrolled, these may lead to eutrophication of the dam. With the parasite species and diversity known, it is recommended that fish health assessments should be conducted along pollution gradients in the system to determine whether it can be incorporated into the suite of biomarkers for water quality monitoring of the Sesmyl Spruit system.
Prof. A. Avent-Oldewage

M.Sc.
The catchment area of the Olifants River has, over a number of years, been exposed to extensive mining, agriculture and urbanisation activities in the Witbank-Middelburg and Phalaborwa regions which has largely contributed to the deterioration of water quality. Of major concern is the influence anthropogenic activities have on the aquatic ecosystem of the Olifants River within the Kruger National Park and how me health of fish residing In these waters is affected. To determine fish health, a biological monitoring method, the Health Assessment Index (H41), was tested for the first time In South Africa. Four surveys were conducted at Mamba and Balule In the Olifants River, Kruger National Park during 1994 (February, May, July and November). An additional survey was conducted in February 1995 at Loskop Dam. Samples of water and sediment were taken for analysis of metals and physical and chemical water parameters. A maximum of 20 Clarias gariepinus fish were sampled at each location. Evaluation of the fish was done according to guidelines set in the HAI and parasite population composition (prevalence, abundance, mean intensity) was determined. Organ and tissue samples including gills, liver, muscle and skin were analysed for the bioaccumulation of chromium, copper, Iron, manganese, nickel, lead, strontium and zinc, using atomic absorption spectrophotomeby. Metal concentrations in the water at Mamba and Balule were within guideline limits, whereas concentrations at Loskop Dam were above guidelines. As reflected by the application of the Aquatic toxicity Index, Loskop Dam presented with the poorest water quality followed by Mamba then Balule. It was found that certain physical and chemical variables namely fluoride, potassium, sulphate and total dissolved solids concentrations at Mamba and Balule were relatively high, particularly during drier months. Metals accumulated in organs and tissues, with the highest concentrations In the gills followed by the liver, skin and muscle. The discriminant analysis, utilising metal bloaccumulation, discriminates between water quality at Mamba and Balule, revealing a 100 % classification probability for each survey. Values obtained In the application of the HAI indicated that variables with good predictor accuracy were plasma protein, all parasites, endoparasites, liver, white blood cell counts, ectoparasites, skin, fins and gills. The discriminant function for the HAI generally Indicated variables similar to those exhibiting high predictor accuracy. The discriminant function showed relatively low classification probability for each survey. In case 1, where separate endo- and ectoparasite variables were Included in the determination of me discriminant function, probability for me entire study ranged between 47.5 % and 84.2 %. In case 2, where endo- and ectoparasite variables were given a refined score rating system, probability ranged between 62.5 % and 100 %. The low classification probability Indicates either the Importance of repetitive testing for this technique or a total departure from it. Results showed that fish populations with higher HAI values are found in water of poorer quality (Mamba), while healthier fish populations i.e. with lower RAI values are found In water of better quality (Balule). Parasite data shows a similar tendency by indicating that ectoparasites are abundant in water of higher quality, while endoparasftes increase in water of poorer quality. The HAI reflects the condition of fish populations in relation to their aquatic environment, therefore, the HA/ gives an indication of water quality and should be used as a first level screening tool. If complemented by a parasite survey, distinguishing between endoand ectoparasites, the results from the HAI will be enhanced.

M.Sc.
There are 39 known species of Lamproglena to date. A review of all species including the species name, the author, as well as an accompanying sketch and information regarding the distribution, pathology and host preference is given. Lamproglena clariae is a copepod gill parasite found on Clarias gariepinus. It has been observed that they cause extensive gill tissue proliferation, which may interfere with respiration. It is uncertain on which tissue type Lamproglena feeds, as red blood is never apparent in the gut of Lamproglena monodi, whereas in the cases of both L. clariae and L. barbicola they undoubtedly feed on blood, proven by the frequently blood-filled gut. Even thought the mouthparts are not fully understood as yet, it is deduced that feeding involves only the maxillae and maxillipedes. Many poecilostomes lacks mandibles. Also, in the lernaeids the mandible is appendage is the smallest and from the 39 known Lamproglena species, the mandibles are described in only eight species. This study examines the digestive tract and the structure of the mouthparts using both light and scanning electron microscopy and tracts the nerves to establish if L. clariae does possess mandibles. Specimens were collected from Clarias gariepinus in the Vaal Dam after the fish were euthanised and the gills removed. The samples were fixed in an aceto formaldehyde alcohol solution and preserved in 70% ethanol prior to dehydration and embedding in resin. Serial section were made at 5 pm and stained with a trichrome stain. A schematic as well as graphic reconstruction of the digestive system is presented. The digestive system consist of three predominant parts, the fore, mid and hindguts. The foregut has a cuticularised epithelium. The oesophagus has a muscle layer iv which stretched and contracts in order to aid feeding and it extends into the midgut via a funnel-like structure. There are four designated zones within the midgut. The hindgut is a simple, cuticle lined tube. Cell structures are discussed. The bilobed protocerebrum in L. clariae is present. The deutocerebrum innervates the antennules. The tritocerebrum consist of two lobed parts and innervates the antennules. The ventral nerve cord is situated posterior to the cephalon. It protrudes dorsally, from where the posterior commissures innervates. The anterior commissures innervates closer to the tritocerebrum. The nerves leading to the mandibles are innervated from the anterior commissure. The more posteriorly located commissure innervates the nerve to the seta located between the antennae and the maxillae. Both the nerves to the maxillae and the endopodite to the maxillae are innervated from this commissure. Mandibles were left out of previous species descriptions of L. clariae. Other Lamproglena species descriptions, showing the mandibles, revealed slender looking mandibles located in close proximity to the mouth opening. This is contrary to the stout mandibles of L. clariae. Future research topics are highlighted and discussed

M.Sc.
The Vaal Dam subcatchment is located in the upper reaches of the Vaal River. As a result the water quality is reasonably good. In contrast the Vaal River Barrage catchment includes the PWV area, resulting in poorer water quality. During this study, a fish Health Assessment Index (HAI) successfully tested in previous studies on the Olifants River System was applied to the Vaal River System. The aim was to determine if the HAI could distinguish between the Vaal Dam and Vaal River Barrage with regards to water quality. Surveys were conducted bimonthly from November 1998 to February 2000. Physical water quality variables were measured. Water and sediment samples were also collected and analyzed (Institute for Water Quality Studies, Department of Water Affairs and Forestry) to verify the HAI results. Rand Water Board and the Department of Water Affairs and Forestry also made water quality data available. Twenty sharptooth catfish, Clarias gariepinus, were collected from both localities with the aid of gill nets. Fish were checked for external parasites on the boat. On land fish were weighed and measured, after which blood was drawn and slime smears made. Blood and slime smears were examined under a light microscope for parasites. The HAI examination was performed after severing the spinal cord. Internal parasite numbers were recorded. From the parasite data collected infestation statistics were calculated. Four variations of the Parasite Index (PI) were incorporated in the HAI and results compared. During each survey gill arch, gill filament, muscle, skin and liver tissues were collected from each fish. These were analyzed for strontium, aluminium, chromium, manganese, iron, lead, copper, zinc and nickel concentrations using atomic absorption spectrophotometry. Differences in water and sediment trace metal concentrations between localities were small. Metal concentrations in fish tissues recorded from both localities were also almost identical. Possible explanations for this trend were discussed in the relevant section. Highest metal concentrations were generally recorded in gill tissue followed by liver, skin and muscle. Physical water quality variables (salinity and conductivity), and macro water analysis (e.g. phosphate and nitrate) indicated that water quality at the Vaal River Barrage was poorer. The HAI confirmed this. Higher index values were recorded from the Vaal River Barrage, with the converse being true for the Vaal Dam. Regression analysis indicated that plasma protein, haematocrit and the index value obtained using the Inverted Parasite Index, most successfully predicted (70 %) from where a randomly chosen fish were collected. When viewing index values obtained using the four versions of the PI, all four distinguished between localities. The discriminatory ability of the Inverted PI was slightly higher than that of the other PI's. It is concluded that the HAI distinguished successfully between the Vaal Dam and Vaal River Barrage on the grounds of water quality. Poor fish health correlated with decreasing water quality (salinity and eutrophication).