Hidrológiai Közlöny 2000 (80. évfolyam)

5-6. szám - XLI. Hidrobiológus Napok: "Vízi ökoszisztémák (taxonómia, biodíverzitás, biomonitorozás, élőhelyek frakmentációja, inváziós fajok biológiája)" Tihany, 1999 október 6-8.

281 remi Megyei Búvárklub munkatársai. Hölvényiné Nagy Katalin és Polgárdiné Klein Tünde segített a minták feldolgozásában Minden segítségért hálás köszönetünket fejezzük ki Irodalom Biró, K & P. Gulyás (1974) Zoological investigations in the open water Potamogelon perfoliatus stands ofLake Balaton Annal. Biol. Tihany 41: 181-203. Entz, G„ O. Sebestyén (1942) A Balaton élete Magyar Természettudományi Társ., Budapest, 1-366. Kir/iichenko, M. Ya. (1968) Phenology, population dynamics, and growth of Dreissena larvae in the Kuibyshev Reservoir. - In: Biology and control of I>reissena, ed.: Shtegman B. K, Nauka, Moskva, Leningrad, 1964. Israel Program for Scientific Translations, Jerusalem 1968,p 15-24. Kozák l.., lakatos Gy., Kiss K. A/., Kerti A. (1998) A tihanyi köves parton kialakuló élőbevonat zonációjának és benépesülési dinamikájának tanulmányozása. Hidrológiai Közlöny 78 (5-6): 353-354. lakatos Gy., L. Kozák, K. M. Kiss, M. Kiss, A. Kerti (1997) A Balaton köves parti-öv élöbevonatának előzetes tanulmánvozása. - Hidrológiai Közlöny 77 (1-2): 33-35. Muskó I. B. (1992) Amphipoda species found in Lake Balaton since 1897. - Miscnea zool. Hung 7, 59-64 Muskó I. B. (1994) Occurrence of Amphijxxla in Hungary sincc 1853. Crustaceana 66, 144-152. B. Muskó, /. és A. R. Russo (1998) Amphipoda rákok betelepülése mesterséges alzatra a Balatonban Tihanynál. - Hidrológiai Közlöny 78 (5-6): 269-272. Muskó, /. /?., A. R. Russo (1999) Importance of Corophium curvispinum G. O. Sars, 1895 (Crustacca: Amphipoda) in l^ake Balaton (Hungary) - A colonization study. - Cnistaccana, special volume 1999: Crustaceans and the Biodiversity Crisis. IVoccedings of the Fourth International Crustacean Congress, Amsterdam,The Netherlands, July 20-24 1998, vol. I. F.d.: Frederick R. Schram and J. C. von Vaupel Klein, Brill, Leiden, Boston, Köln 1999: 445-456. Sebestyén, O. (1934) Appearance and rapid increase of Dreissensia polymorpha Pall and Corophium curvispinum G. O. Sars forma devium Wundsch in lake Balaton Magy. Biol. Kut. Münk. 7: 190-204. (In Hungarian) Sebestyén, O. (1938) Colonization of two new fauna-elements of Pontus-origin (Dreissensia polymorpha Pall and Corophium curvispinum G. O. Sars forma devium Wundsch) in Lake Balaton - Verh. Internat. Ver. theor. angew. Limnologie, 8: 169-181. van der Velde, G„ B. G. P. Paffen & F. IV. B. van den Brink (1994) Decline of zebra mussel populations in the Rhine Competition between two mass invaders (Dreissena polymorpha and Corophium curvispinum). Naturwissenschaften 81: 32-34. Colonization of natural substrata in Lake Balaton. Methods and preliminary results Muskó, /. II and Sz, Görög Abstract: Natural substrata (10 x 10 x 2 cm wood pieces and handful stones) were placed into I.ake Balaton at Tihany 100 m from the shore (water depth: 2,5 m.) on a Stative to which iron frames were attached near the bottom, in the middle and near the water surface. The substrata were hanging from the frames. The experiment started 15th-16th July 1999, we took samples biweekly altogether four times with the help of divers. The dry mass of coating, the Chlorophyll-a content of the coating and the Chlorophyll-a content of the algae in the water sampled parallel were determined. We measured the temperature, turbidity, dissolved oxygen, conductivity and pH near the bottom, in the middle and near the water surface three times in order to check the stratification. 32 animal taxa and groups were identified, the larvae of zebra mussel (Dreissena polymorpha) and the amphipod Corophium curvispinum dominated, the juveniles of the latter dominated at the start. The relationships of the dominance differed according to the nature of the substrata and according to the water strata. However, C. curvispinum was dominant on the stones on the shore sampled parallel. The density of colonizing animals reflected the mass of the coating (excluding animals) only at the first two weeks of the experiment, later the interspecific relationships determined the specific composition of the animals on the surface of the substrata. The density of all the animals (ind. m"

1 wood surface) increased until the fourth week, declined thereafter, changed between 22300 and 424500. The density of D. polymorpha changed between 5700 and 331500, that of C. curvispinum changed between 2400 and 52300. The definite dominancy of zebra mussel at first moderated up to the sixth week while the density of C. curvispinum gradually raised. Our results draw attention to the importance of these two pontocaspic invasive immigrants in the littoral zone of Lake Balaton.. Keywds: natural substrata, Dreissena polymorpha,, Corophium curvispinum.