Abstract

Parasitic crustaceans are the most abundant animals on the planet. However, these organisms are responsible for the remarkable ecological and economic damage both in the world and in Algeria.The examination of the gills of 776 fishes belonging to four species of freshwater fishes caught in the Beni Haroun dam (Mila, Algeria): Luciobarbus callensis, Carassuis carassuis, Cyprinus carpio and Abramis brama, has allowed the collection of 249 ectoparasite Copepods belonging to eight species attached to four genera and two families: Ergasilus sieboldi, Ergasilus peregrinus, Ergasilus briani, Neoergasilus japonicus, Ergasilus megaceros, Neoergasilus longispinosus, Paraergasilus brevigiditus, Lernea cyprinacea respectively. However, We note the absence of individuals belonging to the class of isopods.

The study considered the determination of epidemiological parasite indices according to seasons, size, sex of the fishes, and the microhabitat. The distribution of parasitic indices showed that Cyprinus carpio is the most infested species by parasitic copepods with Abramis brama being the least infested. The parasitic copepods Neoergasilus japonicus, Ergasilus sieboldi and Ergasilus briani have the highest infection rates. An infestation rate by parasite copepod varies from one season to another for Carassuis carassuis while it is higher in summer and autumn for Luciobarbus callensis and Cyprinus carpio. For Abramis brama and Lucibarbus callensis, this rate is zero in winter. The statistical analysis of the data shows that season and size have effects on parasitic infestation in the four species while sex and microhabitat have no effect.

Principal correlation analysis is used to show the effect of physicochemical parameters on parasitic infestation. It is found that the number of parasite is positively correlated with temperature, dissolved oxygen, orthophosphate, and Nitrites and Ammonium. However, it is negatively correlated with pH and Nitrates and this during both Summer and Autumn periods.
Also, the statistic analysis show clearly that the number of parasites is negatively correlated with the male gender of Cyprinus carpio and positively correlated with the size of Luciobarbus callensis.

Our results on the effects parasites have on the growth of Cyprinus carpio reveal that parasitism causes slower growth of parasitized fish (K = 0.16) compared to non-parasitic fish (K = 0.46). This is obtained by calculating the condition index K which characterizes the state of health of fish. Additinally, the application of the diversity indices such as specific richness, SHANNON-WEAVER and SIMPSON shows that parasitic diversity by host species is remarkable in Carassuis carassuis followed by Cyprinus carpio. The parasite diversity is found to be high during Summer and Autumn periods. Finally, the calculation of the IndVal value makes it possible to deduce based on the criterion host species, that 2 and 3 indicator species for Carassuis carassuis and Cyprinus carpio respectively. Based on the seasonal criterion, the IndVal value reveal 3 indicator species for both summer and spring periods.

Key words: Parasitic crustaceans, Beni Haroun dam, parasitic indices, Abiotic parameters, Growth, Specific richness, parasite diversity.

Information

Item Type:	Thesis
Divisions:	» Faculty of Natural Sciences and Life
ePrint ID:	1740
Date Deposited:	2019-05-19
Further Information:	Google Scholar
URI:	https://www.univ-soukahras.dz/en/publication/article/1740

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