Endoparasitaemia of Chrysichthys Nigrodigitatus in a Tidal Freshwater Body in the Niger Delta, Nigeria

Abstract

One hundred Chrysichthys nigrodigitatus were randomly selected from the New Calabar River to determine the effect of size and sex on the endoparasitaemia in the blood, heart, liver, kidney and Gastro-intestinal tract. The formol-ether concentration method was used to examine the samples. Data revealed an overall parasitaemia of 18 (18.0%). The size classes 301-400mm, 201-300mm and >169-200mm had 5(55.6%), 12(15.2%) and 1(11.1%) respectively while the size class 0.05), however the females had 11(20.4%) and the males had 7(15.2%) of their respective populations. Site specific endoparasitaemia showed that the gastro-intestinal tract harboured the highest (38.9%) parasitic load, while the kidney had the lowest (5.6%). The heart had (33.3%) and the blood and liver had (11.1%) parasitic load each. Fourteen (14) parasite species from 5 phyla were recovered from the fish samples namely: Protozoa - Coccidia sp. and Thelohanellus piriformis; Platyhelminth - Ascocotyle ceolostoma, Sanguinicola inermis, Sanguinicola armata, Atalostropion sp., Silurotaenia siluri, Tetrochetus coryphaenae, Biacetabulum appendiculatum and Tetraonchus monenteron; Nematoda - Strongyloides sp.; Acanthocephala - Acanthocephalus lucii and Neoechinorhynchus rutili; and Crustacea - Alebion elegans. Endoparasitaemia in the sampled population was influenced by the physico-chemical properties of the water body which is greatly affected by the intrusion of salt into the river due to its tidal conditions. However, the relatively high endoparasitaemia in the gastro-intestinal tract was associated with the nutrient rich ambience of the intestine which may allow easy establishment and multiplication of parasites.