Species diversity and population dynamics of freshwater leeches in the rivers of the east of Tehran

Leeches as one of the most important components of the aquatic ecosystem has gained so much attention. Due to their parasitism, they are commercially considered as dangerous factor in fishery and biologically as potential indexes for chemical pollutant in aquatic ecosystems. So their identification and population dynamics in different aquatic habitats would be valuable. Species diversity of fresh water leeches in three rivers in east of Tehran province, Lar, Jajrood and Hablehrood rivers, were studies through 6 months in 2015. During the sampling procedure from 10 station in 3 rivers, two species, Placobdella costata and Erpobdella octaculata were collected which the latter was more frequent in all the sampling points. Study on population dynamics of Erpobdella octaculata showed no significant difference among different sampling points; however, population in different sampling months showed significant difference and the most collected samples belonged to May; it was assumed that the highest population in May would be due to the higher population of their host Ephemeroptera, favorite temperature of water and low level of chemical pollutants.