Distribution and ecology of leeches (Hirudinea) in brackish waters of the German Baltic

Abstract

The knowledge about records of leeches (Hirudinea) in Baltic brackish waters of north-east Germany (Mecklenburg- West Pomerania) will be summarized. Observations were made from estuaries of rivers (Stepenitz and Warnow) and lagoons (Darss-Zingst, Stettin) as well in Baltic offshore waters (especially at the Adlergrund/Rønnebank). Altogether 33 taxa are established probably including a new Piscicola species. All species of Glossiphoniidae, Haemopidae and Erpobdellidae could live both in freshwater and oligohaline brackish water up to salinities of 2 psu, few of them even up to 3.6 psu. Only species of the family Piscicolidae are able to penetrate (or to find their optimum?) into mesohaline waters (here up to 13 psu). In the present study several first records for Germany were made in brackish waters (Piscicola kusznierzi, P. elishebae and P. wiktori). Further noteworthy observed species were shortly introduced (Glossiphonia paludosa, Placobdella costata, Italobdella epshteini, Haemopis elegans and Dina apathyi). 7 host fish species could be observed so far.