Aspects of the ecology ofCichlidogyrus philandercollected fromPseudocrenilabrus philander philanderfrom the Padda Dam, Gauteng, South Africa

Abstract

Cichlidogyrus philander was originally described from Pseudocrenilabrus philander philander in Lake Kariba, Zimbabwe. Specimens from four fish species were collected during this study over a 14-month period from the Padda Dam, Johannesburg, transported to the laboratory and killed. Following examination, only P. p. philander was found to be infected with C. philanderindicating strict host specificity. Parasite intensity varied from 0 to 184 specimens per fish. Although no significant correlation between season and the infection of specimens of C. philander occurred, a maximum mean intensity of 91.6 occurred in winter. The prevalence was 100% in 10 of the 14 surveys, with no preference for host sex. Mean intensity of infection correlated positively with total length of the host and more parasites were present on fish with a higher condition factor. The distribution on the gill arches shows no significant difference between the number of parasites from gill arches on the left and right sides of fish. More parasites were present on the third and second gill arches, with the majority dorsally, on the distal ends. Water quality variables showed no correlation between prevalence, abundance or mean intensity of this parasite.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa. I. Winter survey versus summer survey comparison from Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841) hosts

“…Similar results have also been obtained by other researchers (Anderson et al 1993, Blažek and Gelnar 2006, Turgut et al 2006, Le Roux et al 2011). Paling (1968 demonstrated that most of the respiratory current appears to flow over the third pair of gills, with smaller yet appreciable volumes flowing over the second and fourth pairs of gills.…”

“…Previous studies (e.g. Turgut et al 2006, Le Roux et al 2011) also indicated no significant differences in gill set preference. It is thus believed that the significant preference observed in summer may have been the result of a random effect.…”

“…This is once again most probably the result of water flow and water pressure on the dispersion of parasites during the respiration process (Le Roux et al 2011). This preference was found to be statistically significant during the winter survey only.…”

“…Cusack 1986, Cone and Cusack 1988, Le Roux et al 2011. Variation in the condition factor also reflects the state of sexual maturity and degree of nourishment (Williams 2000Ali et al 2006, Froese 2006.…”

Seasonal occurrence and microhabitat specificity of Paradiplozoon ichthyoxanthon Avenant-Oldewage in Avenant-Oldewage et al., 2014 (Monogenea: Diplozoidae) infecting Labeobarbus aeneus (Burchell) (Teleostei: Cyprinidae) from the Vaal Dam, South Africa: water quality and host size as determining factors?

“…Crafford et al (2014) indicated that site preference was linked to season, with significant differences in site preference of monogeneans from Labeo umbratus during summer but not winter. Le Roux et al (2011) indicated site preference in Cichlidogyrus philander Douëllou, 1993 for the third and second gill arches, concluding that due to a lack of correlation between gill filament length and number of primary and secondary lamellae with parasite prevalence, site selection is governed by water flow over the gills. The distribution of diporpas of P. ichthyoxanthon indicates greater numbers attached to the middle arches and can be linked to large volumes of water washing over the middle gill arches facilitating attachment (Wootten 1974, Dzika 1999.…”