The use of a scoring card system to assess the suitability of underground and surface water for the farming of warm water fish species in five districts in Limpopo Province

Makhamisi, Hlengani John (2019-04)

Thesis (MPhil)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: The development of aquaculture to meet the local and global market demand for fish as an affordable protein source, has created the need for the screening of alternative water sources (i.e. underground and surface water) for its physicochemical properties to assess whether it is suitable for fish production. With wild stocks being characterized by over-utilisation, aquaculture presents a solution to meet the protein needs of rural communities in many countries and to overcome the problems experienced in wild capture fisheries such as over-exploitation and shortages in supply. This study aimed to assess the quality of underground and surface water for aquaculture production in five districts in the Limpopo Province of South Africa, i.e. the Vhembe, Mopani, Capricorn, Sekhukhune and Waterberg. A scorecard, based on guidelines on suitable water quality standards as published by different authors, was developed and used to collect data from the study areas. Ten physicochemical parameters, including dissolved oxygen (DO) (mg/L), temperature (°C), pH, turbidity (NTU), total dissolved solids (TDS) (mg/L), phosphorus as phosphate (PO4, mg/L), and salinity (ppm) were analysed in order to determine the suitability of the water for aquaculture development. The mean and standard deviation of results were calculated for the physicochemical parameters, whereby averages were determined for sampling sites from a single type of water body, i.e. for both underground and surface water bodies used in each district. Water samples were collected at scheduled times (i.e. 10h00, 12h00 and 15h00) from randomly selected earthen ponds, stagnant concrete ponds and water stored in Jojo tanks, respectively. Samples were then analysed according to standard methods. Results obtained showed that with the exception of dissolved oxygen and phosphorus in Mopani, Sekhukhune and Capricorn districts, all other parameters considered were within the recommended suitable ranges for fish farming of the candidate species. Where certain low and high scores are observed for parameters, water treatment is recommended to improve the water quality, as this may otherwise have potential negative effects on the sustainability of productivity of aquaculture in the long term. Water treatment can optimise the application of underground and surface water for fish farming, and with continuous monitoring of all parameters, successful aquaculture development can be maintained. The scorecard system provided a user-friendly, basic tool to rapidly assess the suitability of warm water resources for fish farming of candidate species, such as Mozambique tilapia (Oreochromis mossambicus), African catfish (Clarias gariepinus) and Common carp (Cyprinus carpio) in the Limpopo Province of South Africa.

AFRIKAANSE OPSOMMING: Die ontwikkeling van akwakultuur om die plaaslike en wêreldwye markvraag na vis as 'n bekostigbare proteïenbron te voorsien, het die behoefte geskep vir die ondersoek van alternatiewe waterbronne (bv. ondergrondse- en oppervlakwater) vir fisies-chemiese eienskappe om te bepaal of dit geskik is vir visproduksie. Met natuurlike visbronne wat gekenmerk word deur oorbenutting, bied akwakultuur 'n oplossing om die proteïenbehoeftes van landelike gemeenskappe in baie lande te bevredig en om die probleme wat ondervind word in wildvangste-visserye soos oorontgining en tekorte aan voorsiening te oorkom. Hierdie studie het ten doel om die gehalte van ondergrondse- en oppervlakwater vir akwakultuurproduksie in vyf distrikte in die Limpopo Provinsie van Suid-Afrika, insluitende, Vhembe, Mopani, Capricorn, Sekhukhune en Waterberg te evalueer. 'n Telkaart gebaseer op riglyne oor geskikte watergehaltestandaarde soos deur verskillende skrywers gepubliseer, is ontwikkel en gebruik om data vanuit die studiegebiede te versamel. Tien fisies-chemiese parameters, insluitende opgeloste suurstof (DO) (mg/L), temperatuur (°C), pH, troebelheid (NTU), totale opgeloste vastestowwe (mg/L), fosfor as fosfaat (PO4, mg/L) en saliniteit (ppm) is ontleed om die geskiktheid van die water vir die ontwikkeling van akwakultuur te bepaal. Die gemiddelde en standaardafwyking van resultate is bereken vir die fisies-chemiese parameters, waardeur gemiddeldes vir steekproefpersele vir enkele soort waterbron bepaal is, d.w.s. vir beide ondergrondse- en oppervlakwaterliggame wat in elke distrik gebruik word. Watermonsters is geneem op geskeduleerde tye (o.a. 10h00, 12h00 en 15h00) van lukraak geselekteerde gronddamme, stagnante betondamme en water gestoor in Jojo tenks, onderskeidelik. Monsters is dan volgens standaardmetodes ontleed. Uitslae het getoon dat met uitsondering van opgeloste suurstof en fosfor in Mopani-, Sekhukhune- en Capricorn distrikte alle ander parameters oorweeg was binne die aanbevole geskikte reekse vir visboerdery van kandidaatspesies. In gevalle waar sekere lae en hoë tellings vir parameters waargeneem word, word waterbehandeling aanbeveel om die gehalte te verbeter aangesien dit op die lang termyn moontlike negatiewe uitwerking op die volhoubaarheid van die produktiwiteit van akwakultuur kan hê. Waterbehandeling kan die aanwending van ondergrondse en oppervlakwater vir visboerdery optimaliseer, en met volgehoue monitering van alle parameters kan suksesvolle akwakultuurontwikkeling gehandhaaf word. Die telkaart stelsel bied 'n gebruikersvriendelike basiese instrument om die geskiktheid van warmwaterhulpbronne vir visboerdery van kandidaatspesies, soos Mosambiek tilapia (Oreochromis mossambicus), Afrika-katvis (Clarias gariepinus) en gewone karper (Cyprinus carpio) in die Limpopo Provinsie van Suid-Afrika te bepaal.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106065
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