Mercury, silver, selenium and other trace elements in three cyprinid fish species from the Vaal Dam, South Africa, including implications for fish consumers

AbstractThe egg release–mating comparison, heterospecific matings and mating success under two hybridization conditions – (i) mixing one sex per species and (ii) mixing both sexes from each species – were investigated to determine whether silver bream Blicca bjoerkna and common bream Abramis brama can hybridize in nature.The results revealed that non-matings in hybridization experiments of silver bream females × common bream males can be explained by territorial and aggressiveness activities observed in common bream. In common bream females × silver bream males, heterospecific matings were observed but their numbers were significantly lower than the spawning numbers, and in this experiment, a female mated with one to four heterospecific males. In mixing both sexes from both species, similar spawning – mating numbers were observed but heterospecific matings accounted for only 27% of the total matings, with 24% accounting for heterospecific matings between common bream females and silver bream males, directly or by opportunism. Mating success was characterized by the occurrence of fertilized eggs after matings.Natural hybridization occurred preferentially between common bream females and silver bream males.

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Occurrence of Tetracampos ciliotheca and Proteocephalus glanduligerus in Clarias gariepinus (Burchell, 1822) collected from the Vaal Dam, South Africa

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v80i1.522 ◽

2013 ◽

Vol 80 (1) ◽

Cited By ~ 3

Author(s):

Grace Madanire-Moyo ◽

Annemariè Avenant-Oldewage

Keyword(s):

South Africa ◽

Digestive Tract ◽

Standard Length ◽

Feeding Habits ◽

Clarias Gariepinus ◽

Male And Female ◽

Mean Intensity ◽

Gill Nets ◽

Larval Stages ◽

Vaal Dam

Cestodes are parasitic flatworms that live in the digestive tract of vertebrates as adults and often in the liver, muscle, haemocoel, mesentery and brain of various animals as larval stages. To identify the cestodes infecting Clarias gariepinus Burchell, 1822 (sharptooth catfish) in the Vaal Dam, a total of 45 host specimens were collected with the aid of gill nets between October 2011, January and April 2012. The fish were sacrificed and examined for cestode parasites. Two adult cestodes, Tetracampos ciliotheca Wedl, 1861 (prevalence 86.7%, mean intensity = 15, n = 45) and Proteocephalus glanduligerus (Janicki, 1928) (prevalence 51.1%, mean intensity = 5, n = 45) were found in the intestines of the catfish. Both T. ciliotheca and P. glanduligerus are new locality records. There were statistically insignificant differences in the infection of the male and female C. gariepinu. Fish with standard length ranging from 40 cm – 54 cm (≥ 3 years) had the highest prevalence and mean intensity while those ranging from 10 cm – 24 cm (< 1 year) had the lowest prevalence and mean intensity for both cestodes. The study highlights the importance of changing feeding habits of C. gariepinus with age on the prevalence and mean intensity of the two gastrointestinal cestode parasites.

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Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa

Koedoe ◽

10.4102/koedoe.v54i1.1059 ◽

2012 ◽

Vol 54 (1) ◽

Cited By ~ 4

Author(s):

Jan A. Venter ◽

Bruce Q. Mann

Keyword(s):

South Africa ◽

Law Enforcement ◽

Fish Species ◽

Protected Area ◽

Surf Zone ◽

Marine Protected Area ◽

Fish Populations ◽

Estuarine Fish ◽

Catch Per Unit Effort ◽

Preliminary Assessment

A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

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DNA Fingnerprinting of Eight Cyprinid Fish Species of Iraqi Inland Waters Using RAPD-PCR Technique

Advances in Life Sciences ◽

10.5923/j.als.20120202.03 ◽

2012 ◽

Vol 2 (2) ◽

pp. 9-16

Author(s):

Mustafa Sami Faddagh ◽

Najah A. Hussain ◽

Adnan Issa Al-Badran

Keyword(s):

Fish Species ◽

Cyprinid Fish ◽

Inland Waters ◽

Rapd Pcr

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Paradiplozoon vaalense n. sp. (Monogenea: Diplozoidae) from the gills of moggel, Labeo umbratus (Smith, 1841), in the Vaal River System, South Africa

Journal of Helminthology ◽

10.1017/s0022149x1300059x ◽

2013 ◽

Vol 89 (1) ◽

pp. 58-67 ◽

Cited By ~ 16

Author(s):

Q.M. Dos Santos ◽

B. Jansen van Vuuren ◽

A. Avenant-Oldewage

Keyword(s):

South Africa ◽

Sequence Data ◽

Light And Electron Microscopy ◽

River System ◽

Ribosomal Gene ◽

Its2 Region ◽

Genetic Characteristics ◽

Vaal River ◽

Vaal Dam ◽

Second Internal Transcribed Spacer

AbstractAn unidentified monogenean diplozoid species was collected from the gills of moggel in the Vaal River and Vaal Dam, South Africa. Specimens were removed from gills of the hosts and observed using light and electron microscopy to compare these diplozoids with known species. The second internal transcribed spacer (ITS2) of the ribosomal gene was amplified, sequenced and compared to that of other diplozoid taxa. Morphological species delimitation was used to determine the identity of these diplozoids, but they did not match the description of any diplozoid taxa. This species is recognized by the specific size of the hooks, number of plicae in posterior and trapezoid anterior projection of the median sclerite connecting to the clamp jaws via a single sclerite, occasionally with two small additional sclerites. Genetic characteristics based on sequence data from the ITS2 region also distinguish this taxon from all other diplozoid taxa. This South African diplozoid grouped in the same clade as Paradiplozoon ichthyoxanthon Avenant-Oldewage, 2013. Data clearly indicate that diplozoids collected from moggel represent a new, distinct taxon of Paradiplozoon Akhmerov, 1974 and are described here as Paradiplozoon vaalense n. sp.

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