Condition Factor and Observable Disease Manifestation of Clarias gariepinus (Burchell, 1822) obtained from Non-Wild Ponds in Ibadan, South-Western Nigeria.

Abstract

The study compared the condition factor and observable disease manifestation in 405 randomly and maturely selected Clarias gariepinus in Ibadan. The condition factor as a measure of well-being was calculated using the formula K=100W/L³. Out of the 405 apparently healthy fish, 302(74.57%) were found within condition factor (CF) range of 0.6-0.79 and 62(15.31%) within those with 0.8-0.99. The condition factor of >1.0 had 13(3.21%) of fish, while the least number of fish 4(0.98%) were observed within the least CF of 0.39. The mean weight of fish progresses from 339.3±90.3g to 696.0±211.6g as the CF increased from (0.39 - >1.0) and so did the standard length increase from 30.78±3.61-35.52±3.50cm. Higher mean weight of fish (446.1±11.70g) found within 0.39 CF could be due to the little number of fish encountered in the category.  There were significant differences between both mean of the weight, the standard lenght of fish and the CF (p<0.05). However, the relationship between the CF and the total length showed no significant difference (p>0.05). Microscopic observation of the organs studied revealed no gross significant signs in the fish organs as follow, skin (91.10%), gills (96.79%), intestine (96.79%) and liver (98.02%). Disease manifestation in the skin included white spots in 19(4.2%), tail rot 12(2.96%), peel in 5(1.23%) fishes, while in gills 13(3.21%) showed pale colour which suggest anaemic situation, however no physical diseases were manifested in the intestine except for observed varying contents such as green algae, coloured exudates, and cannibalized fish. The liver samples in each case had 3(0.74%) that showed poor texture and yellowish exudates. While most fish were in moderate condition (CF 0.60- 0.79) and appeared healthy both internally and externally, the study thus highlighted few signs of physical diseases. However, due to the absence of microbiological and histopathological screenings, the study recommends further aetiological investigations to improve fish diagnosis and management.