Differentiating the Gyrodactylus Species an Ectoparasite Infection of Guppy Poecilia reticulata

Abstract

Guppies (Poecilia reticulata) from natural populations are prone to infections from several species that potentially have a profound impact on their life history evolution. Ornamental fishes are very important source for the transmission of parasites to new sites and to different countries along the transcontinental movements of fish hosts. Poecilia reticulata is a common ornamental fish representing tropical guppy all over the world. This serves as a host for a wide variety of parasites ranging from protozoans to metazoans. Gyrodactylus turnbulli and Gyrodactylus bullatarudis found to infect Poecila reticulata. G. turnbulli is reportedly a specialist which is found caudally on the host whereas G. bullatarudis is considered a generalist occurs more rostrally on the host. Gyrodactylus sp causes mass mortalities to the ornamental fishing industry therefore the identification of the parasite is important. The identification of species lies mainly on the opisthaptoral armature specially the hamuli, marginals in association with the penis. Earlier the cirrus pouch was used for to discriminate the different species of Gyrodactylus. Flat preparations of the worms were made and fixed with Malamberg’s fixative and the measurement of hamuli and marginals were made under the light microscope. The measurements made were subjected to image analysis software. The immunopholerescent staining techinique with pholoiden used for study the different structures at different depth with the help of a confocal microscopy were used in the present study. The opisthaptor muscular arrangements with the distribution of flame cells together with the detailed structure of the pharynx have been carried out. The opisthaptor showed a ring like muscular arrangement and the muscular path is more intense as two bundles towards the median hamuli. The musculature enhances firm attachment with the help of marginals and median hamuli, affecting the osmoregultion and causing the death of the fish host.