GEOGRAPHICAL RANGES OF MICROSPORIDIA FAMILY GLUGEIDAE – FRESHWATER FISH PARASITES A. V. Tyutin, E. N. Medyantseva Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Yaroslavl Region, 152742, Russia; e-mail:
[email protected]
ȺɊȿȺɅɕ ɆɂɄɊɈɋɉɈɊɂȾɂɃ ɋȿɆȿɃɋɌȼȺ GLUGEIDAE – ɉȺɊȺɁɂɌɈȼ ɉɊȿɋɇɈȼɈȾɇɕɏ ɊɕȻ Ⱥ. ȼ. Ɍɸɬɢɧ, ȿ. ɇ. Ɇɟɞɹɧɰɟɜɚ ɂɧɫɬɢɬɭɬ ɛɢɨɥɨɝɢɢ ɜɧɭɬɪɟɧɧɢɯ ɜɨɞ ɢɦ. ɂ.Ⱦ. ɉɚɩɚɧɢɧɚ ɊȺɇ, 152742, Ȼɨɪɨɤ, əɪɨɫɥɚɜɫɤɨɣ ɨɛɥ., Ɋɨɫɫɢɹ; e-mail:
[email protected]
At first several species of microsporidia infecting freshwater fish were attributed to the family Glugeidae Thelohan, 1892 just because they formed small xenomas in host tissue (Issi, Voronin, 1984; Canning, Lom, 1986). The use of electron microscope allowed revision of the taxonomic position of some of microsporidia species. Formerly many species of the family were assigned to the genus Glugea Thelohan, 1891. A new classification for members of the family, including a new genus Loma Morrison et Sprague, 1981 was developed lately. Since the 1940s in the European part of Russia the main reason for changes in natural habitat of hydrobionts and geographic ranges of their parasites has been a change of the hydrological regime of the Volga River system. Probably in the Volga River basin covering 1/3 of this area between the Baltic and Caspian Sea only microsporidia, which form small xenomas in the intestine walls of percid fishes, should be considered as aboriginal species. Here there are Glugea sp. Voronin et al., 1997 from perch (Perca fluviatilis) for the Middle Volga region, Loma acerinae (= Glugea acerinae Jirovec, 1930) from ruffe (Gymnocephalus cernuus) for the Upper Volga basin and Glugea luciopercae Dogiel et Bychowsky, 1939 most typical for zander (Stizostedion lucioperca) for the Volga delta (Tyutin, 1999). Other species were introduced by their hosts after the regulation of the Volga River. The development of the Volga reservoirs and active construction of inter-basin canals favoured expansion of many new fish species into non typical water-bodies. Only a few invasions of fish in the Volga basin were 232
a result of acclimatization works and many species extend their range spontaneously. As a result at present more than ten invasive fish species inhabit the Upper Volga reservoirs (Slynko et al., 2000). For example, in the second half of the 20th century Lota lota and Osmerus eperlanus (limnetic smelt) spontaneously penetrated Rybinsk Reservoir from Beloye Lake situated further North via Sheksna River. As a result the parasite fauna of this region was enriched with two Microsporidia species: Glugea fennica Lom et Weiser, 1969 and Glugea hertwigi Weissenberg, 1921. On the contrary, Caspian kilka Clupeonella cultriventris Nordmann, 1840 a southern species, which was always typical for the brackish zones of the Caspian Sea penetrated into Rybinsk reservoir only in 1994. At present this herring fish is a basic species in communities of pelagic fish in all large water bodies of the Upper Volga basin (Slynko, 2001). Therefore we expect introduction new microsporidia species (Glugea bychovskyi Gasimagomedov et Issi, 1970) in this area. In recent years the expansion of Caspian bullheads of the genus Neogobius into Middle and Upper Volga is also conditioned by changes in hydrological regime. As a result another microsporidia species Glugea shulmani Gasimagomedov et Issi, 1970 may be introduced here with the goby hosts. The study was financially supported by RFBR (project ʋ 02-04-48440).
