Hindawi Publishing Corporation he Scientiic World Journal Volume 2013, Article ID 206590, 10 pages http://dx.doi.org/10.1155/2013/206590 Research Article New Records of Lake Baikal Leech Fauna: Species Diversity and Spatial Distribution in Chivyrkuy Gulf Irina A. Kaygorodova 1 and Nikolay M. Pronin 2 1 Limnological Institute of Siberian Branch of Russian Academy of Sciences, 3 Ulan-Batorskaja Street, Irkutsk 664033, Russia 2 Institute of General and Experimental Biology of Siberian Branch of Russian Academy of Sciences, 6 Sakhyanova Street, Ulan-Ude 670047, Russia Correspondence should be addressed to Irina A. Kaygorodova; irina@lin.irk.ru Received 14 March 2013; Accepted 16 May 2013 Academic Editors: K. Halaˇ cka, L. Kratochvil, and M. D. Mccue Copyright © 2013 I. A. Kaygorodova and N. M. Pronin. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he study of several Lake Baikal leech collections ofered us the possibility to determine species diversity in the Chivyrkuy Gulf, the biggest one in the lake. As a result, the irst information on the Chivyrkuy Hirudinea fauna (Annelida, Clitellata) has been revealed. here are two orders and four families of leeches in the Chivyrkuy Gulf: order Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and order Arhynchobdellida (families Erpobdellidae and Haemopidae). In total, 22 leech species and 2 subspecies belonging to 11 genera were identiied. Of these, 4 taxa belong to the family Glossiphoniidae (G. concolor, A. hyalina, A. heteroclita f. papillosa, and A. heteroclita f. striata) recorded in Baikal for the irst time. Representatives of 8 unidentiied species (Glossophinia sp., Baicaloclepsis sp., Baicalobdella sp., Piscicola sp. 1, Piscicola sp. 2, Erpobdella sp. 1, Erpobdella sp. 2, and Erpobdella sp. 3) have been also recorded. he checklist gives a contemporary overview of the species composition of leech parasites, their hosts, and distribution within the Chivyrkuy Gulf. he analysis of spatial distribution has shown that the leech species diversity is correlated with the biological productivity of the bay. he most diverse community of leech species is detected in the eutrophic zone of the lake. 1. Introduction he intensive 200-year study of Lake Baikal found that it is the oldest (25–30 million years), the deepest (1637 m), and the largest (23 000 cubic km) repository of fresh water on the planet (20% afordable drinking water), with the status of the Natural World Heritage sites (Merida, 1996). Although Baikal is one of the most studied lakes in the world, there are still “white” spots. One of them is the Chivyrkuy Gulf, the largest and the least studied part of the lake. Nevertheless, the Chivyrkuy Gulf is a unique ecosystem. Not by chance, the prominent limnologist and Baikal researcher Vereshchagin, relying on the results of his irst Circum-Baikal expedition, came to an unambiguous conclusion that the best place to study activities at Lake Baikal was the Holy Nose Peninsula, which forms the western shore of the Chivyrkuy Gulf [1]. However, in those days, the proximity of transport com- munications played a decisive role in establishing scientiic stations in the southern Baikal (Bolshie Koty, Listvyanka). herefore, the Chivyrkuy Gulf stood aside from the routes of the majority of academic expeditions for a long time. he Chivyrkuy Gulf is located in the north-eastern part of Lake Baikal (Figure 1). With an area of about 270 km 2 , maximal width of 13 km, and length of 27 km, the Chivyrkuy Gulf is the most deeply intrusive and isolated gulf in Lake Baikal [1]. he western and eastern shores of the gulf form a chain of bays (Figure 1). Chivyrkuy Gulf has a uniform bottom rising deep into the gulf. Only in its transit there are depths of over 100 m. Most of the gulf has a depth of less than 25 m [2]. In its low-lying water-logged part of the south shore (with a depth of up to 4 m), there is a runof from the adjacent Lake Arangatuy. he bottom of Chivyrkuy is predominantly sandy and, only at the outlet of the gulf, at a depth of more than 20–30 m is covered with silted sand and then grey silt [3]. Black or brown silt covers the bottom of the multiple bays. Rocky bottoms are poorly represented. Some features of morphometry, temperature, and glacial regimes, and certain hydrobiological characteristics allow