Abstract   

    From February 1999 to January 2000, 120 silver carps (Hypophthalmichthys molitrix) were collected at Pirowal Fish Hatchery Khanewal (Punjab, Pakistan) and were examined for copepod ectoparasites. Out of 120, only 12 specimens (10%) of silver carps were infested. Six species of Lernaea (L.) recorded were L. cyprinacea Linnaeus, 1761; L. polymorpha Yu, 1938; L. oryzophila Monod, 1932; L. lophiaru Harding, 1950 and L. ctenopharyngodonis and L. arcuata Soejanto, 1965. The overall prevalence was highest for L. cyprinacea (9.16%) followed by L. polymorpha (6.66%) L. lophiara (3.33%), L. oryzophila (2.5%) L. ctenopha (2.5%) and L. arcuata (1.6%). L. polymorpha and L. cyprinacea were the most abundant species than the other ectoparasites in multiple infestations. Parasites were not found in the smallest and the largest fishes and number of parasites decreased as the weight of the fish increased.   

Key words: Silver carp, fish, Lernaea spp., copepod ectoparasites