A histology-based fish health assessment of the tigerfish, Hydrocynus vittatus from a DDT-affected area

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dc.contributor.author Smit, Nicholas Jacobus
dc.contributor.author McHugh, K.J.
dc.contributor.author Van Vuuren, J.H.J.
dc.contributor.author Van Dyk, J.C.
dc.contributor.author Bervoets, A.
dc.contributor.author Covaci, A.
dc.contributor.author Wepener, V,
dc.date.accessioned 2012-11-27T07:36:46Z
dc.date.available 2012-11-27T07:36:46Z
dc.date.issued 2011
dc.identifier.citation Smit, N.J. 2011. A histology–based fish health assessment of the tigerfish, Hydrocynus vittatus from a DDT–affected area. Physics And Chemistry Of The Earth, 36:895-904. [ URL ] en_US
dc.identifier.issn 1474-7065
dc.identifier.uri http://hdl.handle.net/10394/7783
dc.description.abstract The Pongolapoort Dam (PPD) in the Phongola River, Kwa-Zulu Natal, South Africa and the surrounding area are classified as intermediate to low risk malaria areas and are continually being treated with DDT for malaria vector control. DDT is known as an endocrine disrupting chemical posing estrogenic and anti-androgenic properties and therefore might impact on the health of the 18 freshwater fish species found within this system. Of these species the tigerfish, Hydrocynus vittatus, is targeted by both recreational and local subsistence fishermen and was recently included in the South African threatened or protected species list. Their protected status and importance as a food source therefore emphasises the need for their health status elucidation. Previous research on H. vittatus in the Phongola floodplain highlighted DDT biomagnification in this species. Recent data show that the sum of the DDT levels in February 2009 (5403.9 ng/g lipid) and July 2009 (5537.4 ng/g lipid) is still comparable to the high levels found 30 years earlier. The aim of the current study was thus to determine the health status of H. vittatus in relation to DDT exposure by means of a histology-based fish health assessment protocol. Tigerfish were collected in February 2009 (n = 30) and July 2009 (n = 15) and gill, kidney and liver tissue were subjected to histological analyses. Mean Index values showed that the Kidney Index (IK), Gill Index (IG) and Fish Index (IFISH) were higher in fish from the February survey while the Liver Index was higher in those collected during July. Liver alterations identified included intercellular oedema, granular degeneration, vacuolation, nuclear pleomorphism and lymphocyte infiltration. Kidney alterations included dilation of the glomerulus capillaries, vacuolation and hyaline droplet degeneration. Gill alterations identified included telangiectasia and hyperplasia of the secondary lamella, congestion, and rupture of pillar cells. Although histological alterations were observed, the histology based fish health assessment protocol indicated that the H. vittatus population in PPD were in a healthy state. The histological assessment did not reflect the DDT exposure induced effects that were anticipated. However, the biomagnification effects in other tertiary consumers in the PPD such as crocodiles and fish eagles cannot be ruled out. en_US
dc.description.uri http://dx.doi.org/10.1016/j.pce.2011.07.077
dc.language.iso en en_US
dc.publisher Elsevier en_US
dc.subject DDT en_US
dc.subject fish health assessment en_US
dc.subject histology en_US
dc.subject hydrocynus vittatus en_US
dc.subject Pongolapoort dam en_US
dc.subject Jozini dam en_US
dc.title A histology-based fish health assessment of the tigerfish, Hydrocynus vittatus from a DDT-affected area en_US
dc.type Article en_US

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