This study reports the presence of Enterogyrus cichlidarum Paperna, 1963 (Monogenoidea: Ancyrocephalidae) in the stomach of Nile tilapia, Oreochromis niloticus Linnaeus, 1758, cultured in the State of Santa Catarina, Southern Brazil. A total of 98 fish originating from a fish pond culture in Joinville, South Brazil, were examined. The fish were collected in the winter of 2007, in the summer, autumn, winter and spring of 2008. After anesthetized and sacrificed in a benzocaine solution, their  stomachs were removed, bathed in 55°C water, fixed in 5% formalin for quantification and attainment of the prevalence rate, mean intensity, mean abundance and mounted in Hoyer's. Prevalence rate throughout the period was 94%. The greatest mean intensities occurred in August 2008 and November 2008, followed by July 2007, January and May 2008. The great majority of Monogenoidea are branchial and ...

Few studies have been done to evaluate the monogenean microhabitat preference. This study evaluated the monogenean distribution among different gill arches of Nile tilapia Oreochromis niloticus and seasonality. A total of 89 fish were captured in a pond located in Chapecó, Santa Catarina, for parasitological analysis. After fish euthanasia, the gill arches were removed, separated from the most external to the most internal and named as I, II, III and IV. Transparency, pH, oxygen, temperature, alkalinity, conductivity, ammonia, iron, orthophosphate, sulfide, nitrite and nitrate of water pond were measured. In spring 2008 the mean abundances of the monogeneans (Scutogyrus longicornis, Cychlidogyrus sclerosus, C. thurstonae and C. tilapiae) in the arches I, II, III and IV were, respectively, 11.45, 14.45, 13.8, 13.15, in summer 2008 theywere 13.12, 12.25, 14.94, 21.53, in summer 2009 they ...