Fourteen farms from Krishnagiri, Thiruvarur, Thanjavur and Nagapattinam districts of Tamil Nadu was surveyed to study the incidence of parasites in Genetically Improved Farmed Tilapia (GIFT). Among the 14 farms selected, seven farms practiced polyculture of carps and GIFT and seven farms practiced monosex tilapia farming. The study was carried out to find the level of incidence between the two farming practices. Samples from polyculture farms revealed that the higher infection of Argulus in order Rohu > Catla > Mrigal no infection on GIFT. Out of the seven polyculture farms, four farms revealed Argulus infection and no infection of parasite was observed in three farms. Among the seven farms practicing monoculture of tilapia, no Argulus infection was observed. Monogenean trematodes like Dactylogyrus was identified in three farms and no infection of parasite was identified in remaining four farms. Protozoan Parasites like Trichodina, Apiosoma, and Tetrahymena was identified in both culture practices. In both culture practices, Lernaea was not noted on Tilapia but observed on Indian Major Carps (IMC). Study on the different management practices adopted in the selected farms revealed use of antiparasitic agents and organic agents use in nine farms and three farms respectively for parasite control and the remaining two farms does not adopt any treatment methods. Common antiparasitic agents such agent as Cypermethrin, Dichlorvas, Ivermectin and deltamethrin were used as parasitic control. During the study period, unwarranted method of treatment of parasites was observed.
Fish is one of the important food source which supplies low cholesterol and high protein to approximately 60% of the World population. Most of the developing countries obtain 30% of the annual animal protein requirements from fish. Parasitic infections cause less production and high economic losses by direct fish mortality. Under natural conditions, 50 to 90% of freshwater fishes harbor at least one species of parasites. The selection of a certain host species by ectoparasites must be governed mainly by factors in the host surface. Thus, chemical stimuli emitted from the host have been suggested to attract the parasites and even initiate certain behavioral and physiological changes in the parasite. The parasitic infection give indications of water quality since the parasite infection level commonly increase with organic load. Parasites and their host usually live in equilibrium. However, in crowd conditions of the host, such as in fish ponds parasitic diseases can spread very rapidly and cause heavy mortality. The paper deals with the incidence of fish parasites in farms of Tamil Nadu. The paper also documents the treatment and management measures adopt