Occurrence of some nematode parasites in the gastrointestinal tract of Ariidae (Teleostei: Siluriformes) catfish, Arius arius (Hamilton, 1822) from Karachi coast

Current study was carried out in December, 2014 to investigate the occurrence of helminth parasites in catfish species belonging to family Ariidae (Blecker, 1862). Four species of catfishes namely Arius arius (Hamilton, 1822), Arius caelatus (Valenciennes, 1840), Arius dussumieri (Valenciennes, 1840) and Arius sona (Hamilton, 1822) off the Karachi coast were screened for the occurrence of helminth parasites. Fish were examined after washing contents of gastrointestinal tract and observed under light microscope with the help of regular parasitological methods. The nematode parasites namely; Raphidascaris acus (Bloch, 1779) larvae, Metabronema magnum (Taylor, 1925), Haplonema immutatum (Ward et Magath, 1917) and Hedruris bryttosi (Yamaguti, 1935) were recorded from the gut of the catfish, Arius arius (Hamilton, 1822). These are new host records as these parasites have not been reported from Arius arius species in the region, off the Karachi coast.