L. Forró szerk.: Miscellanea Zoologica Hungarica 7. 1992 (Budapest, 1992)
Muskó, I. B.: Amphipoda species found in Lake Balaton since 1897
heamobaphes were present from May to middle of August. Because of the small amount of D. villosus in the samples, we were not able to evaluate the data. The juveniles of the C. curvispinum and D. haemobaphes species hatched in the spring, reached maturity and produced offspring in the summer of the same year, while the summer and autumn generation reproduced next year. The abundance and biomass of the latter two species decreased in the middle of summer, while they showed high values in autumn (Fig. 3). The reason might be partly the prédation of fish or other organisms on the amphipods in the lake and partly the vigorous growth of the macrophytes in the summer months. Biomass Abundance (drywt/g dry wt) ( ind/g macrophyte wet wt) 1C8 6 ig«7 M 0 *\t hi Fig. 3. Abundance and biomass of C. corophium and D. haemobaphes at different times of sampling Taking into account the data of Varga & Tóth (1986) concerning the biomass of submerged macrophytes in Lake Balaton, we could roughly estimate the biomass of C. curvispinum and D. haemobaphes: 11 and 0.1 g animal dry wcight/m respectively in August 1986 near the Tihany peninsula where the water was covered byM. spicatum. We can conclude that the present-day species composition of amphipods in the sampled areas of Lake Balaton is very similar to the species composition recorded during the 60s, three pontocaspian amphipod species do occur in the lake and C. curvispinum is the dominant species. Summary 1. There were only few amphipod species simultaneously present in Lake Balaton, the species composition changed from time to time. Gammaruspulex was found in the lake in the last century, while in the 1930s years G. roeseli and the pontocaspian Corophium curvispinum were present. Since the 1950s G. roeseli disappeared and pontocaspian Dikerogammarus species (D. haemobaphes and D. villosus) appeared in the littoral zone of Lake Balaton.
