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Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa
Dissertation (MSc)--University of Pretoria, 2019.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2019
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| _version_ | 1867613678649475072 |
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| access_status_str | Open Access |
| author2 | Steyl, Johan Christian Abraham |
| author_browse | Steyl, Johan Christian Abraham |
| author_facet | Steyl, Johan Christian Abraham |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/71655 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:58.102Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/71655 Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa Steyl, Johan Christian Abraham u89105291@tuks.co.za Scarfe, David Taylor, Gillian Denise UCTD Tilapia Ammonia Gill pathology Veterinary science theses SDG-02 Veterinary science theses SDG-03 Veterinary science theses SDG-12 Dissertation (MSc)--University of Pretoria, 2019. This study evaluated eighteen commercial farms within Gauteng, Northwest and Limpopo provinces, where a representative sample of grow-out fish from each farm, was humanely euthanased, weighed, measured, and each fish’s overall health assessed through microscopic examination of skin and gills. A full necropsy and histo-pathological evaluation of all key organs followed. Farm production parameters were assessed by means of a questionnaire with a detailed history and a comprehensive water analysis that included water temperature, dissolved oxygen, CO2, ammonia, nitrite, nitrate, pH, hardness and alkalinity. These production parameters, together with stocking density and underlying nutrition, were compared with the macro- and microscopic findings for positive and negative correlations / relationships. Significantly high burdens of ecto-parasites and very poor water quality, with compromisingly low dissolved oxygen and temperatures, and high carbon dioxide and nitrite, were found in association with severe gill pathology. This was compounded by inadequate filtration for the density of fish stocked, with resultant toxic nitrogenous waste accumulation. Other key abnormalities observed were chronic-active hepatic lipid oxidation, low hepatocellular lipid, evidence of secondary opportunistic infectious disease, and extremely poor growth. Poor farm management practises were prevalent, with evidence of uneconomical fish sex ratios, and poor implementation of biosecurity and disease management. The study serves to highlight the factors that currently dominate as critical issues affecting overall health and growth of aqua-cultured tilapia in the South African context. TM2019 es2026 Paraclinical Sciences MSc Unrestricted SDG-02: Zero hunger SDG-03: Good health and well-being SDG-12: Responsible consumption and production 2019-10-09T14:22:50Z 2019-10-09T14:22:50Z 2019/09/04 2019 Dissertation Taylor, GD 2019, Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/71655> S2019 http://hdl.handle.net/2263/71655 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Tilapia Ammonia Gill pathology Veterinary science theses SDG-02 Veterinary science theses SDG-03 Veterinary science theses SDG-12 Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title | Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title_full | Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title_fullStr | Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title_full_unstemmed | Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title_short | Health assessment of tilapia (Oreochromis spp.) aquaculture systems in the northern provinces of South Africa |
| title_sort | health assessment of tilapia oreochromis spp aquaculture systems in the northern provinces of south africa |
| topic | UCTD Tilapia Ammonia Gill pathology Veterinary science theses SDG-02 Veterinary science theses SDG-03 Veterinary science theses SDG-12 |
| url | http://hdl.handle.net/2263/71655 |