Studies On Fish Parasitic Diseases Pathogenic Species And Epidemiological Investigation In The Kashgar Langan Reservoir

The frequent outbreak of parasitic diseases in fishes has severely damaged the fishery in Kashi Prefecture along with thevigorous development of aquaculture. However, there is no accumulation of relevant preliminary works in Kashi. Forcollection of relevant data, we selected Langan Reservoir and investigated the causes of parasitic diseases infecting fishesthere. According to the methodology of fish parasitic fauna, we collected fishes from Langan Reservoir in the spring (May)and fall (September)2013. We sampled a total of7species including446fishes and certain parasite specimens. The aims ofthis investigation were to clarify the pathogenic species, damages, prevalence and post-medication preventive effects of theparasitic diseases infecting the fishes there. Here we report the major results and conclusions.(1) The446fishes were classified into7species: Pseudorasbora parva Temminck et Schlegel1842(n=277),Triplophysa (Hedinichthys) yarkandensis (Day)(69), Carassius auratus (Linnaeus)(43), Ctenopharyngodon idellus (Cuvieret Valenciennes1844(26), Cyprinus carpio (Linnaeus)1758(20), Songpu mirror carp (10), and Carnis Megalobramae (1).Then parasites were collected via necropsy according to the fish parasitology investigation methods.(2) Fourteen species of parasites were identified, including Trichodina nobilis, Gyrodactylus sp., Dactylogyrussquameus, D. extensus, D. lamellatus, D. pekinensis, D. sp., Bothriocephalus sp., Ligulidae sp., Capillaria sp., Philometra sp.,Trematoda larva, Caligus sp., and Ergasilus sp., belonging to4phyla,6classes,9orders,10families, and10genera.(3) Of the collected fishes, Pseudorasbora parva and Triplophysa yarkandensis were mostly wild and highly infected by7and6species of parasites respectively. In particular, the Philometra sp. that infected Pseudorasbora parva also affectedTriplophysa yarkandensis. Of the14species of parasites, the infection rates of Trematoda larva and Dactylogyrus lamellatuswere relatively high (33%vs.38%). The infection intensity of Trematoda larva was the highest and reached93/fish in theeyes of Ctenopharyngodon idellus. The dominant parasite was found to be Trematoda larva via computation of dominance.(4) Based on morphologic and molecular biology methods, the Philometra sp. infesting Pseudorasbora parva andTriplophysa yarkandensis was identified to be an18S rDNA sequence. In comparison with sequences of the same family inGenBank, the homogeneity was99.14%, indicating this species was identified.(5) In terms of composition and infection of parasites, we clarified the fauna of parasites infecting the fishes in LanganReservoir, and analyzed the effects of parasitic diseases on local fishery. We provide feasible prevention and control schemeswith favorable effects.