Thesis (M.Sc. (Physiology)) --University of Limpopo, 2015 / Water is an essential and yet scarce resource, which has a vital role for human use and also serve as a habitat for numerous organisms in aquatic environments. Despite its scarcity there have been many reports indicating that it is continually polluted by domestic, agricultural, mining and other anthropogenic activities; subsequently affecting the health of organisms residing in such water bodies. Fish have been selected as the bio-monitoring species due to its direct interaction with the environment; thereby making it an appropriate model to monitor and evaluate the health status of the environment. The feral population of the alien species, Hypopthalmichtys molitrix (Valenciennes, 1844) commonly known as the silver carp in Flag Boshielo Dam has been considered a healthy population. However, this perception changed considerably after reports of lethargic, dying fish were first noted in 2011. Currently the sporadic deaths amongst mature specimens (>0.7m) persist; and the reason(s) for their demise remains unclear. Therefore, the aim was to employ a seasonal study design to investigate the health status of selected fish species such as H. molitrix in Flag Boshielo Dam by evaluating haematological parameters, oxidative stress biomarkers and bio-accumulation levels of particular transition metals. Seasonal surveys were carried out from February 2012 to January 2013 at Flag Boshielo Dam, Olifants River System, Limpopo Province. The locality surrounding the dam is known to be in an agriculture and mining catchment. Hypopthalmichtys molitrix and Labeo rosae (Steindachner, 1894) commonly known as the rednose labeo were collected with the use of scoop nets, conventional angling gear and gill nets. Following collection, morphometric measurements were taken and blood was collected. The blood samples required for further analysis at the Medical Science Department, University of Limpopo were kept on ice (4˚C). After the collection of all blood samples the specific fish was sacrificed and muscle samples were collected for bio-accumulation analysis and gills and liver samples were collected for the measurement of oxidative stress biomarkers. These tissue samples were rapidly frozen and kept frozen (-85˚C) until further analysis. Haematological parameters from the study reflected a variation amongst comparison of the inter- and intra-species. It was observed that mature H. molitrix suffered from anaemia. The response of glutathione-S-transferase (GST) and thiobarbituric acid reactive substances (TBARS) was relatively constant throughout all seasons when the young (<0.5m) and mature H. molitrix (0.6 – 0.90m) specimens were compared. However, the catalase (CAT) response of mature H. molitrix was dramatically impaired. This would increase their vulnerability to oxidative stress. Bioaccumulation levels of the eleven selected transition elements exhibited various trends. Metals such as Molybdenum (Mo), Vanadium (V), (Chromium) Cr, Cobalt (Co), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) exhibited seasonal bio-accumulation levels that were in support of the various feeding behaviours of the fish species in this study. On the other hand, metals such as Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) also illustrated the potential to be contributing factors in the death of the mature specimens. In conclusion, the findings from this study illustrate the complex nature of metabolic disturbances resulting in the death of mature H. molitrix specimens. It is clear that no single aspect investigated in this study could be solely implicated as the major cause of death. This multifactorial presentation necessitates further haematological assessment focussing on blood cell morphology and pathology, as well as investigations into other oxidative stress biomarkers in liver and gill tissue. In addition, identifying the most appropriate tissue type for future bio-accumulation measurements of transition metals in this feral population is necessitated. It is further suggested that neuro-muscular assessments, focussing on neurotransmitters such as γ-aminobutyric acid (GABA) and acetylcholine (Ach), form part of the investigation into the lethargic behaviour of the mature fish.

This study investigated the causes of high level of intra-and inter-population variation known to occur in the morphology of fish in the genus Hypseleotris Eleotride in southern Australia, particularly within the Murray-Darling river system. The three major objectives of the study were, identify the number and distribution of species,determine the genetic structure of the populations and analyse relationships between species and consider the process of speciation in this species complex. The investigation of morphological variation in Hypseleotris confirmed the presence of two well known species i.e. H. compressa and H. galli, in the coastal rivers and also of the inland species H. klunzingeri. Populations of Hypseleotris klunzigeri sensu lato in inland river were found to be very highly variable and analysis using discriminant functions and principle component analysis showed the widespread presence of three forms (A, B1 and B2). The analysis was confused by the presence of north/south clines and upstream/downstream variation in characteristic in each form. After these factors were removed, there was still a great deal of variation in each population. The presence of hybrids between each pair of inland species, identified by both morphological and genetic data, further confused the analysis and makes identification of all specimens to species in the field difficult. Examination of type material of H. Klunzingeri showed that this belonged to form B2. The other forms can be related to the undescribed species, Midgley's carp gudgeon and Lake's carp gudgeon. Keys to the species in the complex in southeastern Australia are given. The morphological and genetic data show that H. compressa and H. klunzingeri are sister species, primarily separated by the eastern uplands. Similarly, the coastal species, H. galli is related to form B1 and more distantly, to form A. Possible scenarios for the complex are given. / Doctor of Philosophy (PhD)

In 2011, Texas experienced the worst drought in recorded history. This has escalated concerns regarding environmental flows needed to sustain freshwater and estuarine systems as human needs are addressed during drought periods. In this thesis, I analyze fish assemblages and water quality variables in order to observe the effects of drought in the lower Neches River below the saltwater barrier located upstream from Beaumont, Texas. Fish and water quality samples were taken during drought conditions during fall 2011 and summer 2012, after a season of rain. During fall 2011, sites surveyed above the barrier had lower salinity but similarly low dissolved oxygen (DO) levels compared with sites surveyed below the barrier. Salinity levels during fall 2011 were relatively high (reaching up to 15 ppt), whereas salinity during summer 2012 never rose above 1.5 ppt. For gillnet samples obtained during fall 2011, fish species richness was higher in December following a series of rain events than during drought conditions in October and November. Although fish species richness was similar between fall 2011 and summer 2012, species composition varied greatly. For seine samples obtained during summer 2012, species richness was higher during May and July (when the barrier was open) than during June and August (when the barrier was closed). Species richness was lowest for sites in closest proximity to a paper mill effluent discharge pipe located below the barrier. Also, species richness was higher at sites above the barrier than at sites below the barrier regardless of whether or not the barrier was closed. Multivariate statistical analyses of gillnet samples revealed a large amount of compositional overlap among fish assemblages, regardless of time period and location; however, analyses of seine samples revealed that fish assemblages above the barrier were different than those from samples obtained below the barrier and that fish assemblages varied based on time period. Results indicate that, during periods of low flow, water quality deteriorates in the Lower Neches River below the saltwater barrier. During these periods of environmental degradation, fish assemblages have reduced diversity and sensitive freshwater species decline in abundance, with some absent from survey samples.

This thesis was focused on invasive fish species, especially prussian carp (Carassius auratus gibelio) and topmouth gudeon (Pseudorasbora parva) in the Sokolov area and their potential impact on native fish species population in the post-mining water reservoirs. The aim was to compare reservoirs with and without specific maintenance.

Many scholarly tasks involve working with contextualized fine-grain information, such as a music professor creating a multimedia lecture on a musical style, while bringing together several snippets of compositions of that style. We refer to such contextualized parts of a larger unit of information (or whole documents), as subdocuments. Current approaches to work with subdocuments involve a mix of paper-based and digital techniques. With the increase in the volume and in the heterogeneity of information sources, the management, organization, access, retrieval, as well as reuse of subdocuments becomes challenging, leading to inefficient and ineffective task execution. A digital library (DL) facilitates management, access, retrieval, and use of collections of data and metadata through services. However, most DLs do not provide infrastructure or services to support working with subdocuments. Superimposed information (SI) refers to new information that is created to reference subdocuments in existing information resources. We combine this idea of SI with traditional DL services, to define and develop a DL with SI (an SI-DL). Our research questions are centered around one main question: how can we extend the notion of a DL to include SI, in order to support scholarly tasks that involve working with subdocuments? We pursued this question from a theoretical as well as a practical/user perspective. From a theoretical perspective, we developed a formal metamodel that precisely defines the components of an SI-DL, building upon related work in DLs, SI, annotations, and hypertext. From the practical/user perspective, we developed prototype superimposed applications and conducted user studies to explore the use of SI in scholarly tasks. We developed SuperIDR, a prototype SI-DL, which enables users to mark up subimages, annotate them, and retrieve information in multiple ways, including browsing, and text- and content-based image retrieval. We explored the use of subimages and evaluated the use of SuperIDR in fish species identification, a scholarly task that involves working with subimages. Findings from the user studies and other work in our research lead to theory- and experiment-based enhancements that can guide design of digital libraries with superimposed information. / Ph. D.

The main aim of the study is to assess the productivity and supply chain of aquaculture projects in Gauteng Province, South Africa. The research adopted the use of quantitative method; and collected data and information from the five regions that make up the province. Both primary and secondary data were collected. The study used correlation analyses to determine the perfect fit or negative fit of some variables to supply chain as well as the consumers‟ reactions to the questionnaires. Gross margin analysis as well as gross profit margin ratio was used to determine the profitability of aquaculture production in the province. Findings of the study revealed underutilization of production capacities of the established fish farms. The fish farmers in the study are currently using 36% of the capacities of the established aquaculture projects in the study area. The profit margin was in excess of 40% in all the projects surveyed. The study further revealed lack of proper, effective and efficient supply chain for aquaculture projects which adversely affect aquaculture growth and sustainability in Gauteng Province / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2018 / This study aimed to determine the effects of water and sediment quality on fish and the effects of land-use on the water and sediment quality of the Steelpoort River system. To achieve these aims, a few objectives had to be met. The water and sediment quality, the level of metal bioaccumulation of two fish species, the level of acetylcholine esterase inhibition in fish brain tissue, as well as changes in land-use over time. The study adds value in the scientific knowledge of the Steelpoort catchment given that there’s little information about it. It is thus a good baseline, which gives direction for further studies conducted within this catchment. The Steelpoort River, is a tributary of the Olifants River system. The Olifants River (Mpumalanga and Limpopo provinces) is a river stressed by anthropogenic activities with the Steelpoort River being a major sub-catchment. The Steelpoort catchment is filled with mines, agricultural activities, and other developments, such as, the construction of a new dam (De Hoop Dam opened 2014), residential areas and malls. The mines within the catchment are mostly platinum and chrome mines. Sampling was conducted for high and low flow at five sampling sites: Two upstream sites, 1 and 2, and three downstream sites 3, 4, and 5. Site 1 is the reference site for the study as this section (ecoregion) was described as “least threatened”. It was hypothesised that high concentrations of metals and nutrients would be present in the water and sediment, and that the metal would be present in fish tissue and would have an effect on human health, that the biomarker AChE would show signs of inhibition within brain tissue, and lastly that land-use characteristics would have an effect on the water and sediment quality, and inhibition of AChE. Water and sediment samples were collected quarterly over a period of a year at five sites, whereas fish samples (Chiloglanis pretoriae and Labeobarbus marequensis) were only collected bi-annually at three sites. The physico-chemical, nutrients, cations and ions, and metals and metalloids were determined. The two fish species were used for metal bioaccumulation and AChE analyses. Human health risk and bio-concentration factor (BCF) analyses were conducted. Using the land-cover details obtained from South African National Biodiversity Institute (SANBI), Department of Environmental Affairs (DEA) and The Council for Scientific and Industrial Research (CSIR), land-use characteristics were determined and evaluated. The in-situ physico-chemical parameters assessed in this study were found to be within acceptable limits of the Target Water Quality Range (TWQR) at all the sites. The Electrical Confuctivity (EC) and Total Disolved Solids (TDS) parameters were highest at Site 5 and lowest at Site 1, this could be due to Site 5 being the last site before the Steelpoort River connects to the Olifants River, hence this site recieves all the ions and solutes from upstream; and the lowest value at Site 1 could be attributed to this site having the least number of lan-use effects. For nutrients, the highest total nitrogen concentration was recorded at Site 5 and the highest phosphate concentration at Site. This river is mesotrophic according to both the total inorganic nitrogen and phosphorus levels. Metals in the water column that were above DWAF guidelines for Aquatic Ecosystems were Al, Ba, Mn and Zn. In the sediment the following metals were above the Canadian sediment quality guidelines: Cd, Cu, Cr and Zn, which can pose a threat to the health of fish through biomagnification through the food chain. Both C. pretoriae and L. marequensis had bioaccumulated metals from the river system. The concentrations of metals in the muscle tissue of C. pretoriae where higher and this could be due to the fact that unskinned samples were used in the case of C. pretoriae. A variety of metals were present in both fish species but Al, Fe, Sr and Zn were present in higher concentrations. Concentrations of metals were highest in samples from Site 5 The human health risk assessment revealed that Pb could cause health related impacts to the humans who consume a single 150 g fish meal once a week in C. pretoriae; and that Co could cause potential risks in the near future. The BCF values revealed that there were more bioconcentrated metals in C. pretoriae than in L. marequensis and this could also be due to different diets. The AChE activity was higher for L. marequensis during high flow at all sites and higher at Site 1 during low flow but lower at Site 5 and equivalent at Site 2 than the AChE activity recorded for C. pretoriae. This could be due to the ability of L. marequensis to expel pesticides from their system before the pesticides affect brain activity by decreasing the function of AChE. Both fish species had more AChE activity during low flow for sites 1 and 2 than during high flow. The high flow AChE activity was higher for Site 5 in both fish species. The results confirm the hypotheses were that metals would be present in fish tissue and would have an effect on human health; and that the biomarker AChE would show signs of inhibition within brain tissue. The agricultural activity has decreased over time within the catchment, from 2000 to 2014 and this could be due to a decrease of fertile land. There has also been a decrease in the mining activity from 2000 to 2009 and then an increase during 2014, where the decrease could be due to the closure of mines at the end of their life span; and the increase in 2014 could be due to the opening of new mines. Residential areas have increased from 2000 through to 2014. The availability of water decreased from 2000 to 2009, and then increased drastically in 2014. The drastic increase is due to the multiple dams that have been built over time in order to provide water resources to the increased population, and also for mining and irrigation purposes. The water quality showed an increase in the NO3, SO4 and PO4; meanwhile the EC has decreased over time. The decrease in EC means that there are fewer ions in the river. The increase in phosphates and nitrates could mean there is a lot of fertilizers and pesticides being used in agriculture even with the decrease in agricultural land-use over the years. The pesticides can also be due to the increase in residential areas, where pesticides are also used to get rid of pests.

Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2017 / In this study data was collected to establish if the water and sediment quality of the Steelpoort River has any effects on macro-invertebrate species. The Steelpoort River is a tributary of the Olifants River system but not much data about the water quality is available. The Steelpoort River is a perennial river (Ashton et al. 2001) situated west of Burgersfort and from there it flows in a north- easterly direction and converges with the Olifants River in the Drakensberg near Kromellenboog. High silt levels in the river, increases the risk of flooding and leads to the smothering of in-stream habitats resulting in loss of some invertebrate and fish species. Sampling of the water, sediment and macroinvertebrates was conducted quarterly at the Steelpoort River at five sites. One site was above the impoundment (De Hoop Dam) and the rest were below the impoundment. A handheld YSI 556™ Multi Probe System (MPS instrument and a Mettler Toledo SevenGo™ conductivity meter were used to measure the physico-chemical characteristics at the sites. The macroinvertebrates were sampled using the SASS 5 bio-assessment protocol (Goodyear & McNeill 1999, Dickens & Graham 2002). Macro-invertebrate samples were collected using a 400 mm x 400 mm SASS net with a 250 μm mesh size. The substrate was disturbed for a period of two minutes to free macro-invertebrates from the substrate. The SASS score for each site was evaluated in the field for three of the five samples. The macro-invertebrate samples were preserved in 70% ethanol and sorted to family level in the University of Limpopo’s Biodiversity laboratory. For the majority of the physico-chemical parameters the most elevated were detected downstream and lowest concentrations were detected upstream. Analysis of variance (ANOVA) indicated that there were no significant differences for electrical conductivity, salinity, and TDS, between the sites (p>0.05). There were however significant differences in the temperature, dissolved oxygen, turbidity, and pH concentrations (p<0.05). The majority of the metals and metalloids in the water (Fe, Mn, V, Co, Zn, Ba, and Cu) were highest at Tiershoek (Site1) and lowest at Steelpoort (Site 4) and Burgersfort Bridge (Site 5).The mean metal concentrations collected showed elevated levels for chromium, copper and zinc, which were above the CCME sediment guidelines. The most abundant macroinvertebrates were from the family Ephemeroptera which are pollution sensitive and good indicators of pollution in aquatic ecosystems. When using the interpretation of the SASS 5 results from Chutter 1995, the mean Average Score Per Taxa (ASPT) scores show that the water quality for Tiershoek (Site 1) and Polopark (Site 3) is natural but the habitat diversity has been reduced. For De Hoop (Site 2) and Steelpoort (Site 4), the mean ASPT score shows that there is some deterioration in the water quality. Finally, for Burgersfort Bridge (Site 5), the mean ASPT score indicates that there is major deterioration in the water quality. Primer statistical analysis indicated that the average dissimilarity between sites showed that the highest dissimilarity was between Tiershoek (Site 1) and Burgersfort Bridge (Site 5) which was conclusive with the results from the macro-invertebrate count and SASS, indicating that there is diverse difference from upstream to downstream. CCA indicated positive correlations between nutrients detected at Steelpoort with Athericidae, Tabanidae, Gomphidae, Baetidae, Elmidae, Planaria, Psephenidae, and Libellulidae which was indicated that water chemistry characteristics exert influence on macroinvertebrates. The results showed that there is degradation of the water quality in river from upstream to downstream with more pollution tolerant species being abundant at Steelpoort (Site 4) and Burgersfort Bridge (Site 5). The most favourable season was autumn and the least summer/spring and this may be attributed to the life cycle of the macro-invertebrate communities / NRF VLIR

Thesis (MSc. (Zoology)) -- University of Limpopo, 2014 / The Olifants River is presently one of the most threatened river systems in South Africa. The Upper and Middle catchments are heavily impacted by anthropogenic activities, however little is known of the status of the river in the Lower catchment in the Limpopo Province. Thus the aim of this study was to evaluate the impact of water quality on the health of Oreochromis mossambicus and Schilbe intermedius at the Phalaborwa Barrage. This was achieved through assessing the water (seasonally) and sediment quality (bi-annually) at three sites in the Phalaborwa Barrage (inflow, middle and the wall). Ten specimens of each of the two selected fish species were seasonally collected using gill nets of different mesh sizes from May 2010 to January 2011. The water, sediment and the dorsal muscle tissues from both fish species were analysed for selected metals at an accredited laboratory by means of ICP-OES spectrometry and the human health risk factor upon consumption of fish contaminated with metals was assessed. Fish health was determined at the field laboratory by applying the HAI, PI and IPI. In addition, the condition factor (CF) was determined for the selected fish species during all seasons. All water constituents with the exception of turbidity during spring (wall), anions (Cl, F and SO4) and cations (Ca, K, Mg and Na) fell within the target water quality range (TWQR) for aquatic ecosystems throughout the study. Inorganic nitrogen concentrations showed eutrophic (spring) and oligotrophic conditions (autumn, winter and summer), while phosphorus indicated eutrophic (autumn, winter and spring) and hypertrophic (summer) conditions throughout the study. There was no significant difference in anions (F=0.07; df=3; p=0.97), cations (F=0.57; df=3; p=0.64) and nutrients (F=0.79; df=3; p=0.56) detected in water. The metals that were detectable in the water samples were: Al, Fe, Sn, B, Sr, Se, Ba, Mn, Sb and As, while in sediment all metals (Fe, Al, Ti, Mn, Ba, B, Zn, Ag, V, Cr, Ni, Sr, Sn, Co, Cu, Cd, Pb, As and Sb) were detected with the exception of Se. The average metal concentrations detected above the TWQR are; Al, Fe, Se, Sn, Sb and As, in the sediment only Cr and Cd were above suggested quality guidelines. There was no significant difference in metals detected in water (F=0.05; i df=3; p=0.98) and sediment (F=1.62; df=1; p=0.21). Higher HAI values were recorded for S. intermedius than O. mossambicus, indicating that O. mossambicus was in better health than S. intermedius. For S. intermedius, parasites contributed the most to the total HAI followed by abnormal liver conditions, haematocrit levels (internal variables) and abnormal gills (external variable). While for O. mossambicus, parasites, liver, haematocrit (internal variables), gills, eyes, fins and skin (external variables) contributed to the HAI values. There was no significant difference in HAI values for O. mossambicus (F=1.9; df=3; p=0.15) and S. intermedius (F=2.58; df=3; p=0.66) throughout the study. The PI and IPI for ectoparasites for both fish species, were higher than the PI for endoparasites. There was a significant difference for PI values of O. mossambicus (F=0.07; df=3; p=0.041) and S. intermedius (F=3.65; df=3; p=0.019) during the study. Oreochromis mossambicus had higher CF values than S. intermedius and both fish species had values that indicated good fish. Metals that were detectable in O. mossambicus muscle tissue included: Ba, B, Zn, Fe, Sr, Al, Mn, Cr, Ag, Pb, Ni, Cu, Se, V, Sb, Ti, Sn and Co, while for S. intermedius Ba, B, Zn, Fe, Al, Cr, Sr, Mn, Cu, As, Pb, Se, Sn, Ag, Ti, Ni, Sb and Co were recorded. There was no significant difference in bioaccumulation levels between the two fish species (F=1.412; df=3; p=0.250). The human health risk assessment indicated that fish muscle tissues are unsuitable for continuous (weekly/daily) consumption. As some carcinogenic metals i.e. Pb, Cr and Sb for O. mossambicus and Pb, As and Cr for S. intermedius were detected at HQ levels of more than 50 times the recommended value of one. In conclusion, the Phalaborwa Barrage is impacted by metals (Al, Fe, Se, Sn, Sb and As) and occasionally with nutrients. The water and sediment quality and metal bioaccumulation have confirmed the latter statement and to a lesser extent the HAI, PI and IPI. The human risk assessment done indicated that continuous consumption of fish by humans, especially O. mossambicus may have adverse effects on the health of humans.

Experience has shown that effective fisheries governance requires a sound understanding of fisheries as systems incorporating both ecological and human dimensions. The Ecosystem Approach to Fisheries requires that the human components of these systems be considered when developing management and governance frameworks. While the potential for inland fisheries to contribute towards societal welfare and the development of rural livelihoods is becoming increasingly apparent, developing South African inland fisheries requires a careful consideration of both their positive and negative impacts, given that they revolve mainly around five of the world‟s top 100 invasive species. This thesis aimed to explore the value of inland recreational fisheries to rural livelihoods in the Amathole District of South Africa, to the regional economy, and to anglers themselves. Three methods were used to isolate this value. Economic impact analysis was used to estimate the combined total economic impact of the 2011 Divisional Tournament (n=31) and the 2012 Amatola Bass Classic (n=100) on the regional economy of the Amathole District, estimated to be R106 625. The travel cost method was applied to data from the 2012 Amatola Bass Classic in order to estimate the social welfare generated by this tournament. The Negative Binomial model, corrected for truncation and endogenous stratification, estimated this value at R 1 960 090. The sustainable livelihoods framework was used to conduct a broad-based analysis of the value of Amatola Wild Trout, the firm which constitutes the fishery surrounding the rural village of Cata. It was found that the fishery had been responsible for a modest pecuniary impact on the community of Cata within its first two years of establishment, although significant improvements in human capital were found to have resulted from the development of the fishery. These results provide insights into the economic dimension of fisheries in the Amathole District, and will prove useful when weighing up the positive and negative impacts of non-native fish species, particularly when informing decisions regarding their potential eradication.