Assessment of fish as bio-indicators of river health in rivers of the southwestern Cape
Date
2002-03
Authors
Hayes, Johan Barnard
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: In this study, the Fish Assemblage Integrity Index (FAll) was applied on three rivers within the
southwestern Cape. This index uses fish as indicators of biological aquatic integrity and is based on
indigenous species expected to be present in biological fish habitats. Fish integrity classes were
calculated for each of the sites in the three rivers studied. Sites 2 and 4 within the Lourens River
were rated as Class C, whereas sites 1 and 3 were rated as Class F and Class D respectively. Sites
1, 2 and 4 within the Palmiet River were rated Class F, whereas sites 3 and 5 were rated as Class E
and Class D respectively. Site 1 within the Hout Bay River was rated as a Class F site, in addition to
sites 2 and 3 been rated as Class A. It is however, suggested that the FAll needs to be adjusted to
accommodate the general low species richness experienced in the southwestern Cape. In addition to
the FAll been applied, the effects of long-term exposure to subtle water quality changes associated
with human activities, specifically potential estrogenic compounds in fish from the Lourens River
were also investigated. The production of the yolk precursor lipoprotein complex, vitellogenin (Vtg)
produced in the liver under estrogen control was employed as biomarker for environmental estrogen
exposure. Male fish from the Lourens River were studied using SDS-PAGE gel electrophoresis.
Results indicated that 60% of male fish showed the presence of Vtg in their plasma. Abnormal
gonad morphology in male and female fish were also assessed using standard histological
procedures. Results from this study indicated no observed abnormalities in either male or female
gonads. The immediate presence of endocrine disrupters with estrogen activity was investigated by
screening water samples from the Lourens, Palmiet and Hout Bay Rivers for estrogen activity.
Results indicated that none of the samples appeared to be cytotoxic. In addition, estrogen activity of
water samples was also investigated by in vitro culturing of water samples with frog, Xenopus
laevis, liver slices. Results indicated that none of the water samples from the three rivers studied
indicated estrogenic activity. Although cytotoxicity and estrogen activity results were negative, the
production of Vtg in male fish suggests further research regarding the presence of estrogenic
substances in these rivers.
AFRIKAANSE OPSOMMING: In die huidige studie is die 'Fish Assemblage Integrity Index' (FAIl) toegepas op drie rivere in die suidwes Kaap. Hierdie indeks gebruik visse as bioindikatore van biologies akwatiese integriteit en is gebasseer op die inheemse visspesies wat verwag word in biologiese vishabitatte. Integriteitsklasse is bepaal vir elke studieterrein in die drie rivere wat ondersoek is. 'n Klas C is bepaal vir studieterreine 2 en 4 in die Lourensrivier. Klas F en Klas D is bepaal vir studieterreine 1 en 3 in die rivier onderskeidelik. 'n Klas F is bepaal vir studieterreine 1, 2 en 4 en Klas E en Klas D bepaal vir studieterreine 3 en 5 in die Palmietrivier onderskeidelik. 'n Klas F is bepaal vir studieterrein 1 in die Houtbaairivier waar 'n Klas A bepaal is vir studieterreine 2 en 3. Dit word egter voorgestel dat die FAII aangepas moet word om die algemene lae spesierykheid wat ervaar word in die suidwes Kaap te akkomodeer. Die reaksie van visse, afkomstig van die Lourensrivier, op die langtermyn blootstelling aan estrogeniese stowwe is ook bestudeer. Spesifieke reaksies van endokriene versteuring, soos vitellogeen (Vtg) produksie in manlike visse is ondersoek deur middel van SDS-PAGE gel elektroforese. Resultate toon dat in 60% van die manlike visse Vtg in die plasma teenwoordig was. 'n Ondersoek na abnormale gonade morfologie in manlike en vroulike visse van die Lourensrivier is deur standard histologiese prosedures gedoen. Resultate hiervan dui op geen sigbare abnormaliteite in die gonades nie. Die onmiddelike teenwoordigheid van endokriene versteurders is bestudeer deur die sitotoksisiteit van watermonsters afkomstig van die Lourens, Palmiet en Houtbaai riviere te bepaal. Resultate dui aan dat geen monsters sitotoksies was nie. Die estrogeenaktiwiteit van die watermonsters is ook ondersoek deur van in vitro kulture van watermonsters saam met padda, Xenopus leavis, lewersnitte gebruik te maak. Geen estrogeniese aktiwiteit is in die watermonsters gevind nie. Al is die sitotoksisiteit en estrogeenaktiwiteit resultate negatief, dui die produksie van Vtg in manlike visse op die noodsaaklikheid van verdere navorsing ten opsigte van die teenwoordigheid van estrogeniese stowwe in drie riviere.
AFRIKAANSE OPSOMMING: In die huidige studie is die 'Fish Assemblage Integrity Index' (FAIl) toegepas op drie rivere in die suidwes Kaap. Hierdie indeks gebruik visse as bioindikatore van biologies akwatiese integriteit en is gebasseer op die inheemse visspesies wat verwag word in biologiese vishabitatte. Integriteitsklasse is bepaal vir elke studieterrein in die drie rivere wat ondersoek is. 'n Klas C is bepaal vir studieterreine 2 en 4 in die Lourensrivier. Klas F en Klas D is bepaal vir studieterreine 1 en 3 in die rivier onderskeidelik. 'n Klas F is bepaal vir studieterreine 1, 2 en 4 en Klas E en Klas D bepaal vir studieterreine 3 en 5 in die Palmietrivier onderskeidelik. 'n Klas F is bepaal vir studieterrein 1 in die Houtbaairivier waar 'n Klas A bepaal is vir studieterreine 2 en 3. Dit word egter voorgestel dat die FAII aangepas moet word om die algemene lae spesierykheid wat ervaar word in die suidwes Kaap te akkomodeer. Die reaksie van visse, afkomstig van die Lourensrivier, op die langtermyn blootstelling aan estrogeniese stowwe is ook bestudeer. Spesifieke reaksies van endokriene versteuring, soos vitellogeen (Vtg) produksie in manlike visse is ondersoek deur middel van SDS-PAGE gel elektroforese. Resultate toon dat in 60% van die manlike visse Vtg in die plasma teenwoordig was. 'n Ondersoek na abnormale gonade morfologie in manlike en vroulike visse van die Lourensrivier is deur standard histologiese prosedures gedoen. Resultate hiervan dui op geen sigbare abnormaliteite in die gonades nie. Die onmiddelike teenwoordigheid van endokriene versteurders is bestudeer deur die sitotoksisiteit van watermonsters afkomstig van die Lourens, Palmiet en Houtbaai riviere te bepaal. Resultate dui aan dat geen monsters sitotoksies was nie. Die estrogeenaktiwiteit van die watermonsters is ook ondersoek deur van in vitro kulture van watermonsters saam met padda, Xenopus leavis, lewersnitte gebruik te maak. Geen estrogeniese aktiwiteit is in die watermonsters gevind nie. Al is die sitotoksisiteit en estrogeenaktiwiteit resultate negatief, dui die produksie van Vtg in manlike visse op die noodsaaklikheid van verdere navorsing ten opsigte van die teenwoordigheid van estrogeniese stowwe in drie riviere.
Description
Thesis (MSc)--University of Stellenbosch, 2002.
Keywords
Rivers -- South Africa -- Western Cape, Stream ecology -- South Africa -- Western Cape, Freshwater fishes -- Ecology -- South Africa -- Western Cape, Water -- Pollution -- Environmental aspects -- South Africa -- Western Cape, Fish populations -- South Africa -- Western Cape