In the present study, Paraergasilus longidigitus Yin, 1954 (Copepoda: Poecilostomatoida) was identified in branchial flaments of Alburnus alburnus Lin.,1758 caught from Enne Dam Lake for the first time in Turkish fauna. The study carried out monthly between June 98 - May 99, and a total of 208 fish was collected. The distribution of parasitic copepods in relation with the length, sex of fish were recorded. The fishes were infested with P. longidigitus with a mean intensity of 6.2 and an prevalence incidence of 56.7%. The infestation prevalence and mean intensity were seasonal with higher levels in autumn with 74.2%. No significant differences were noticed in the infestation of male and female fishes. A slight increase in the infestation prevalence was recorded as the size of fish increased.