Eco-biology is therefore a profoundly respectful approach that establishes the link and relationship between each animal and its environment. Our study was based on the assessment of the diversity of gill parasiting copepods infecting some cyprinid fish, by applying ecological indices widely used in the ecological field.

The study of the effect of abiotic parameters on the number of parasites by applying PCA showed that:Cyprinus carpio and Luciobarbus callensis are the two host species harbouring the highest number of parasite species. the number of parasites is positively correlated with temperature, dissolved oxygen, orthophosphate and ammonium and negatively correlated with pH during both the Summer and Autumn periods.

. ,A study of parasite biodiversity indices by host species reveals that parasite diversity is highest in Carassuis carassuis, followed by Cyprinus carpio.

Analysis of biodiversity by season reveals higher values in Summer and Autumn. The indicator species method revealed, according to the host fish criterion, two indicator species for.