Prevalence, and distribution pattern of Nematode parasites ofsome fish species from Haraz, Babolroud, Tajan and Talar Rivers in Mazandaran Province
Subject Areas : New Technologies in Aquaculture Development
Keywords: Iran, fish, Distribution pattern, Nematoda, Keywords: Prevalence,
Abstract :
AbstractThe rivers of Haraz, Babelrood, Tajan and Talar are among the most important rivers of the Caspian Basin in Mazandaran province which are the migration route of many valuable fish. The aim of this study was to identify and determine the prevalence rate of nematodes among some fish species in these rivers and to define the distribution pattern of the found parasites among these rivers.The field investigations were conducted during the summer of 2018 and approximately, 161 fish specimens including Alburnoides bipunctatus, Capoeta capoeta, Squalius cephalusand Neogobius pallasiwere cuath and transferred alive to the laboratory. Then fish were killed humanlly and after recording some biometrical variables they were examined to detect the presence of nematodes.Measurement of diagnostic variables of nematodes was performed using Axiovision software on images recorded by digital camera and data and results of biometric and parasitological surveys of each fish were recorded in Excel software.The prevalence of nematode species, were used to describe the parasite populations andthe statistical analysis was performed using IBM SPSS Statistics version 20.0 and significance for all tests was judged at P< 0.05. ArcGIS Desktop program version 10.2 used to create the geographical information system database. Three species of nematodes including Rhabdochona denudata, Rh. Fortunatowi and Rh. Hellichiwere isolated from fish intestine. The most abundant species was Rhabdochona denudata (36% prevalence), which was found in all fish species and in all studied rivers. The two species, Rhabdochona unatowi and Rh. Hellichi, had a prevalence of 9.5% and 34% in the Talar and Tajan rivers, respectively. In addition, the highest prevalence of parasites was observed among Alburnoides bipunctatus(36%). Also, Pearson's correlation coefficient between total fish length and infection rate of different nematode species showed that as the host size increased, the prevalence of parasite infection increased. Studies on the distribution patttern of fish parasites reveal the prevalence of parasitic diseases across different geographic regions and identify high risk areas. Therefore, GIS is a useful tool for monitoring the health of aquatic organisms to determine the occurrence or distribution of parasitic species, as well as changes in the rate and prevalence of them.
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