The use of the urogenital papillae of male feral African sharptooth catfish (Clarias gariepinus) as indicator of exposure to estrogenic chemicals in two polluted dams in an urban nature reserve, Gauteng, South Africa

Abstract

The use of the urogenital papillae of male feral African sharptooth catfish (Clarias gariepinus) as indicator of exposure to estrogenic chemicals in two polluted dams in an urban nature reserve, Gauteng, South Africa AbstractThe African sharptooth catfish (Clarias gariepinus) is indigenous to South Africa where it is commonly found in calm waters such as lakes, streams, rivers, swamps and floodplains. The males of this gonochoristic species can be readily distinguished from females via a distinct elongated urogenital papilla with a pointed tip, located just behind the anus. This structure is an androgen controlled secondary sexual characteristic and could potentially be affected by chemicals displaying endocrine disrupting properties during development. Results of previous studies on effects on papillae of different fish species indicated that these structures could be useful as bio-indicators of exposure due to alterations in the structures. This study investigated the occurrence of abnormal morphology in urogenital papillae compared to the macroscopic and microscopic structure of the gonads of presumed male or intersex catfish sampled from the Rietvlei and Marais dams in an urban nature reserve, due to exposure to endocrine disrupting chemicals (EDCs). Macroscopic observation of the UGP, gonad examination after laparotomy and histology were done. Gonadosomatic index (GSI) and Urogenital papilla length index (UGPLI) were determined for all fish collected. Mesenteric fat analyzed for selected alkylphenols and organochlorines showed high levels of especially nonylphenol indicating long term exposure to these chemicals due to bio-accumulation. The GSI indicated that fish with intersex gonads were probably feminized males. It was concluded that use of the UGP alone, without macroscopic and microscopic analyses of the gonads, could not effectively indicate exposure to EDCs.

Disappearing giants: a review of threats to freshwater megafauna

“…In addition, endocrine disrupting organic pollutants are reported to alter the hormonal balance of aquatic animals, inducing developmental and reproductive abnormalities and ultimately leading to a population decline. For example, estrogenic pollution from industrial, agricultural and waste water treatment plant effluents contributed to the occurrence of intersex African Catfish ( Clarias gariepinus ) individuals in South Africa …”

Determination of endocrine disrupting chemicals and antiretroviral compounds in surface water: A disposable sorptive sampler with comprehensive gas chromatography – Time-of-flight mass spectrometry and large volume injection with ultra-high performance liquid chromatography–tandem mass spectrometry

“…The higher presence of pesticides and personal care products (PCPs) in the surface water from Rietvlei Nature Reserve, located in an urban area, compared to surface water from the Albasini Dam in a rural area, reflects the human impact on the Reserve) is cause for concern as production and agricultural use of this organochlorine pesticide was banned under the Stockholm Convention on persistent organic pollutants (POPs) (2009) [41]. Of interest is that DDT, which is thought to be a main cause of endocrine disruption in the Limpopo Province [6,7], and in Rietvlei Nature Reserve [2,42] (although DDT is not used in the Gauteng Province where Rietvlei Nature Reserve is located), was not detected in any of the surface water analyses. Oestrogenic activity was confirmed in drinking water samples from the Limpopo Province [6].…”

The urogenital papillae as an indicator of sexual maturity in male African catfish, Clarias gariepinus, (Burchell, 1822)

“…The fish were killed by severing the spinal cord anterior to the dorsal fin and the length (mm) and width (mm) of the urogenital papillae (UGP) measured. The morphology of the UGP was assessed by calculating the urogenital papillae length index ( L UGP = UGP length/total body length × 100) and urogenital papillae width index ( W UGP = UGP width/total body length × 100; Kruger et al, ). An incision was made on the ventral side of the body and the testes removed from the posterior region of the body cavity.…”

“…The urogenital papillae (UGP) is a secondary sexual morphological structure in male catfish from which spermatozoa are released, it is androgen‐dependent, and therefore its morphology may be directly correlated with the stage of sexual maturity of the fish. The UGP is situated posterior to the anus of some fish and this brought about the assumption that its morphology could provide a useful tool for the initial non‐invasive assessment of the maturity stage of the fish (Das Neves, ; Har, ; Kruger, Barnhoorn, Jansen van Vuren, & Bornman, ; , ; Páll, Mayer, & Borg, ).…”