Distribution and status of the medicinal leech (Hirudo medicinalis L.) in Turkey

A survey of all the major potential habitats in western Turkey showed that medicinal leeches, Hirudo medicinalis L., are widely distributed over the c ountry and are not rare. They occur in practically all suitable habitats an d the only region where they were found to be absent is that of the large r iver deltas in the south of the country (Cukurova deltas, Goksu delta). The re may be zoogeographic reasons for this (Taurus mountains barrier). The ap plication of a semi-quantitative survey method using collecting efficiency (number of leeches collected per hour by a single person) allowed a rapid a ssessment to be made of its status in a large number of wetlands. Leech den sity varied considerably from wetland to wetland, and the results enabled a ranking of the Turkish wetlands to be made according to their importance f or medicinal leeches. Taking both the leech density and the size of leech h abitats into account, the largest populations were identified on the Black Sea coast (Kizilirmak delta, Yesilirmak delta and Karagol Marshes near Sino p) and in inner and south-west Anatolia (Eber Golu, Karamik and Sultan Mars hes). Commercial exploitation for the pharmaceutical industry and for other purposes takes place at only a few places and does not appear to affect th e population seriously. However, many populations are threatened by the dra ining of their habitats.