A Study of Parasitic Copepod Infesting Two Freshwater Fish Populations (Cyprinus carpio and Abramis brama) from Beni-Haroun Dam (Mila) North-East of Algeria

Abstract

Copepods are one of the main fish ectoparasites, commonly known among the parasitism world, due either to their special adaptive capacity or to induce stress in aquatic organisms, as well as the parasitism result is overall a physiological rate affecting the survival of host. This study was, therefore, aimed to investigate the ectoparasite copepods, infesting 277 fishes including 135 of Cyprinus carpio (Linnaeus, 1758) and 142 of Abramis brama (Linnaeus,1758), collected from Beni-Haroun dam (Mila, northeast Algeria). The fishes were subjected to some morphometric measurements and gill dissections and the harvested parasites were afterwards stored and identified. The parasitic indices were determined to examine the effect of size, sex, season and microhabitat on the parasitic infestation by using χ2 test. The gill examination of individuals of the two host fishes led to harvest 135 copepods, including 127 individuals from Cyprinus carpio belonging to five species (Ergasilus sieboldi, Ergasilus briani, Neoergasilus japonicus, Neoergasilus longispinosis and Lernaea cyprinacae) and 8 individuals from Abramis brama belonging to the two species: Ergasilus sieboldi and Ergasilus briani, and hence Cyprinus carpio is the most infested species than Abramis brama. This study also revealed that the parasitic index values were high in C. carpio (P=53.00%; A=3.7; I=6.93) compared to A. brama (P=12,0.5%, A=0.12, I=1.00) during autumn, since no effect on infestation was noticed during winter. The statistical analysis has revealed the effect of season on parasitic copepod infestation in the two fish species (χ2Obs =30,959 > χ20.05 = 7,815, ddl =3), Since there was no effect due to the microhabitat and sex.