L. Forró szerk.: Miscellanea Zoologica Hungarica 10. 1995 (Budapest, 1995)
Gulyás, P., Bancsi, I.; Zsuga, V.: Rotatoria and Crustacea fauna of the Hungarian watercourses
the dominance of eutrophic taxa: Brachionus, Euchlanis, Keratella, Polyarthra spp, Bosmina longirostris, Chydorus sphaericus, Daphnia hyalina, Daphnia longispina, Diaphanosoma hrachyurum, Maina micrura. As a result of the polluted character of the river, in spite of the nutrient supply no biomass increase can be observed downstream, biomass varied between 0.11 -2.28 g/m 3 . 38. Dráva On the Hungarian river section 43 Rotatoria, 5 Cladocera and 4 Copepoda species were found. Larger abundances were not found in any sampling sites probably because of low flow velocities. Especially the number of planktonic microcrustaceans was low. Accordingly, the biomass values varied between 0.03 - 0.69 g/m 3 . Some rare rotatorian species occurred, such as Keratella americana, K. tropica, Lecane ichthyoura, Lophocharis salpina, Tetramastyx opoliensis. Neither the species composition, nor the abundance values changed along the longitudinal section of the river. 39. Mura At Letenye we were only able to record 24 Rotatoria, 1 Cladocera and 1 Copepoda taxa. Frequently occurring rotifer species were Brachionus calyciflorus, B. quadridentatus, Euchlanis dilatata, Filinia longiseta, Keratella cochlearis, Lecane bulla, Polyarthra vulgaris. Biomass value was extremely low in the range of 0.04 - 0.93 g/nr . 40. Rinya Species composition of Zooplankton community of this river was poor, indicated by the occurrence of 17 Rotatoria, 1 Cladocera and 1 Copepoda taxa. Some eutrophic Rotatoria species formed large populations occasionally (Brachionus angularis, B. quadridentatus, Keratella cochlearis, K. cochlearis micracantha, Polyarthra vulgaris). Because of their small body weight however, this biomass was not great (max. 1.11 g/m'). 4L Kerka 25 Rotatoria, and 4 Cladocera species were only recorded from the samples. Both the abundance and biomass values were low, the latter varied between 0.09 - 0.88 g/m 3 . Beside the eutrophic planktonic Rotatoria species a few macrophyte dwelling ones also occurred (Cephalodella forficula, Encentrum plicatilis, Lecane hamata, Trichocerca elegáns), indicating good water quality. 42. Zala The river can be divided into three section on the basis of the species composition of its Zooplankton communities. At the section upstream of Zalaegerszeg in the clean water we identified 27 Rotatoria, 4 Cladocera and 3 Copepoda species. Their biomass varied between 0.09 -1.19 g/m J . Of the Rotatoria species the Cephalodella stereo, Keratella testudo, Mytilina acanthophora and Trichocerca tigris is considered to be rare in Hungary. Among the Crustacea
