The impact of parasitic Helminths on length-weight relationship and condition factor of two fish species from Lesser Zab River at Altun-Kupri/Kirkuk Province, Iraq

A total of 193 fishes from the Lesser Zab River in Altun-Kupri/ Kirkuk Province, Iraq were investigated, belonging to two families namely Cyprinidae (Luciobarbus xanthopterus Heckel, 1843) and Siluridae (93 Silurus triostegus Heckle, 1843) for the impact of parasites helminths on length-weight relationships and condition factor. Three species of helminth parasites were recovered from host fish, namely: Cestoda, Nematode and Acanthocephala. The association between helminthic parasitic infection with length-weight relationship (LWR) and condition factor in two fish species were studied. The results showed that the growth of both fish species exhibited negative allometry because the regression coefficient "b" obtained was <3. The statistical analysis showed that there was a significant difference between infected and uninfected fishes in the b value. Moreover, significantly (p< 0.05) the highest "b" value (2.2042 in L. xanthopterus and 2.8666 in S. triostegus) was recorded in uninfected fish. Condition factor (K) for the infected and uninfected fishes of both fish species were also determined in the current study. The result showed that the condition factor of both fish species was low, but the K factor of uninfected L. xanthopterus was higher (K<1.50) than that of uninfected S. triostegus (K<0.7). It is indicated that L. xanthopterus performed better than S. triostegus in the study areas. The statistical analyses showed that the K factor in both uninfected L. xanthopterus and S. triostegus fishes was significantly (p<0.05) higher than in infected fishes.