Population dynamics of a parasite Pallisentis in two species of fish Channa punctatus and Channa striatus.

In an aquatic environment, there is a profound and inverse relationship between environment quality and disease status of fish. Parasites are one of the most serious limiting factors in aquaculture. Therefore, the present investigation has been undertaken to sort out the population dynamics of Pallisentis (Acanthocephala), in relation to host sex from freshwater fishes, Channa of Rohilkhand region. A total of 517 fishes (Channa punctatus, n = 198 and C. striatus, n = 319) were examined regularly from August 2006 to February 2010. Overall prevalence of Pallisentis in C. striatus was higher in females (67.78%) as compared to males (63.52%). In case of C. punctatus, overall prevalence of Pallisentis was higher in males (53.77%) as compared to females (52.17%) whereas, relative density was higher in females (61.41%) than in males (52.72%). Intensity (2-3 parasite/host, in both sexes), density (1.36 in males and 1.69 in females) and infection index (0.73 in males and 0.88 in females) were recorded.