L. Forró szerk.: Miscellanea Zoologica Hungarica 10. 1995 (Budapest, 1995)

Nesemann, H., Pöckl, M.; Wittmann, K. J.: Distribution of epigean Malacostraca in the middle and upper Danube (Hungary, Austria, Germany)

The construction of the Ludwigskanal, a waterway which has brought in contact the Rhine and Danube system in 1845, probably facilitated the spreading of G. roeseli. However, its invasion of Western Europe had begun earlier, since already in 1835 Gervais had described this species from the vicinity of Paris. In France, G roeseli is still enlarging its distribution area in western (Seine, Loire) and southern (Rhone) direction (Pacaud 1952, Wautier & Roux 1959, Roux 1969). G. roeseli is found in middle and lower courses of summer-cool runnning waters where current velocities are moderate. There, it coexists with G. fossarum. In summer-warm rivers of the lower mountains and plains, where stream velocity is low, G. roeseli often is the typical and dominant gammarid species. It is able to reach very high densities and biomass (Pöckl 1992, Pöckl & Humpesch 1990). Examples for potamon rivers where G. roeseli was often collected, are the Dyje (Sukop 1990), Morava, Lajta, Rába, Rábca, and Zala. In the Danube, G. roeseli was found sporadically, which is in agreement with Roux (1969), who suggested that G. roeseli avoids high current velocities and large rivers, although it may temporally use them as routes of migration. In the Bavarian Danube near Passau and Jochenstein, Kothé (1968) collected numerous G roeseli but did not record Dikerogammarus haemobaphes. According to Foeckler (1987), G. roeseli and G. fossarum seem to avoid the main stream in this section of the Danube, whereas D. haemobaphes is very abundant. Dikerogammarus haemobaphes (Eichenwald, 1841) Material: Danube at Káposztásmeggyer, 21. 09. 1941, leg. Wiesinger; Danube at Dunakömlőd, 11. 09. 1947, leg. Loksa, I.; Danube at Harta, 05. 09. 1991, leg Ofenböck, T. & H. Nesemann; Danube at Dunaföldvár, 11. 09. 1947, leg. Loksa, I., 31. Jan. 1991, leg. Wimmer, R. & H. Nesemann, 5. 09. 1991; Danube at Dunaújváros, 5. 09. 1991, leg. Ofenböck, T. & H. Nesemann; Danube near Szalkszentmárton, 31. Jan. 1991, leg. Wimmer, R & H. Nesemann; Danube at Budapest, 30. 09. 1932, leg. Dudich, E.; Danube at Római-fürdő near Budapest, 20. 09. 1947, leg. Wiesinger; Danube at Budafok, 04. 09. 1947, leg. Dudich, E. & I. Loksa; Danube at Újpest, 16. 09. 1926, leg. Dudich, E.; Szentendrei Duna at Leányfalu, 04. 09. 1991, leg. Ofenböck, T. & H. Nesemann; Danube at Vác, 30. 09. 1930, leg. Dudich, E.; Danube at Nagymaros, 06. 11. 1926, leg. Unger, E. & E. Dudich; Danube at Zebegény, 14. 09. 1946, leg. Dudich, E.; Danube at Esztergom 17. 09. 1947, leg. Loksa, I.; Danube at Dömös, 30. 07. 1927, leg. Dudich, E.; Danube at Nyergesújfalu, 18. 09. 1947; Danube at Komárom, 19. 09. 1947, leg. Loksa, I.; Danube downstream from Gönyü, 03 . 04. 1990; Danube near Ásványráró, 11. 09. 1991; Danube near Lipót, 11. 09. 1991; Danube near Dunaremete, 13. 09. 1991; Danube downstream from Hainburg, 22. 02. 1991, 8. 09. 1991; Danube near Stopfenreuth, 21. 02. 1991; Danube upstream from Bad Deutsch-Altenburg, 16. 02. 1991; Danube, in a secondary branch near Regelsbrunn, 14. 03. 1991; Danube at Regelsbrunn, 11. 02. 1991; Danube at the confluence of the river Fischa near Fischamend, 28. 04. 1991; Danube, deadwater reach Kühwörthcr Wasser between Schönau and Mühlleiten, 20. 10. 1990; Danube near Schönau, 13. 03. 1991; Danube near Mannswörth, 20. 02. 1991, leg. Nesemann, H.; Danube near Korneuburg, 14. 02. 1991, leg. Schay, G. & H. Nesemann; Danube at Zwebendorf, 20. 04. 1991; Danube, from numerous collecting sites between Altenwörth and Krems, 1985-1990, leg. Pöckl, M.; Danube (rkm 2132) near Linz, from the shipping space of two ships and from their hulls 02. 10. 1993; Danube at Linz (rkm 2135), 28. 09. 1994, leg. K. J. Wittmann; Danube at Schlögen, 14. 11. 1989; Danube at Engelhartszell, 14. 11. 1989; Danube upstream from Aschach, 13. 11. 1989, leg. Schwammer, H.; Danube (rkm 2111) at Mauthausen, 29. 09. 1993, leg. K. J. Wittmann; Danube (rkm 2213) near Pyrawang in the confluence of a small stream, 24. 09. 1993; Danube (rkm 2241) at Sandbach, 08. 09. 1994; Danube (rkm 2214) at Erlau, 08. and 23. 09. 1994, leg. K. J. Wittmann; Danube upstream from Passau, 30. 09. 1990, leg. Nesemann, H.; Danube (rkm 2249) at Vilshofen, 23. 09. 1993; Danube (rkm 2301) at Waltendorf, 08. 09. 1994, leg. K. J. Wittmann; Danube near Gaishofen, 30. 09. 1990; Danube at Friesheim, 07. 1990; Danube, in a side-branch near Tegernheim, 30. 09. 1990; Danube at Barbing, 01. 07. 1990, leg. Nesemann, H.; Main-Danube-Canal (rkm 84) near Mittelhembach, 07. 09. 1994, leg. K. J. Wittmann.