بررسي آلودگي به نماتود رافيد آسكاريس در بعضي از ماهيان تالاب انزلي

Occurance and intensity of Raphidascaris acus in some fish species of Anzali wetland in south - west of Caspian Sea (Iran).

A survey has been done on parasites of different fish species (N = 290) from July 1995 to december 1996. Adult R. acus, a nematode , isolated from three fish species including pike (Esox lucius) (N=43), catfish (Silurus glanis) (N = 5), perch {Perca fluviatilis) (N=35) and larvae of the nemetode isolated from three fish species including crucian carp (Carassius carassius) (N=82), tench (Tinea tinea) (N=6) and bream (Abramis brama) (N=20). In pike, the prevalence and the mean intensity ± standard deviation were 72% and 55±4.7 respectively and the nematodes were recovered from intestine. The prevalence and mean intensity ± SD in spring (84.61% and 7.3±5.4) were more frequent than autumn (56.5% and 3.31 ±1.93). Furthermore, its prevalence and mean intensity were closely correlated with size (length and weight). Crucian carp harboured the larvae of the R. acus in the tissue of intestine The prevalence and mean intensity ± SD of the nematode in this fish were 24% and 4.1 ±3.67 respectively. Furthermore, the prevalence and mean intensity in spring (42.85 and 6.0±5.06) were more than autumn(15.62% and 3.5±3.21). The prevalence and mean intensity were closely correlated with the size of fish. The parasite was recovered from perch (2.9% and 5), tench (33% and 35), bream (10% and 3) and catfish (20% and 6) but not from other fish species such as common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and pikeperch (Stizostedion lucioperca).