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

Gulyás, P., Bancsi, I.; Zsuga, V.: Rotatoria and Crustacea fauna of the Hungarian watercourses

Crustacea faunas are poor. Only 42 Rotatoria and 1 Cladocera species were found during the investigations. Zooplankton biomass varied greatly. During the spring floods it was low, that was followed by an enormous mass production in summer period. In the overall sampling period here, at the Maros, was the highest biomass measured, 74.71 g/m

3 on the whole watershed, indicating polytrophic condition. Water quality of this particular river is largely influencing the Tisza Zooplankton communities both from qualitative and quantitative point of view. 25. Main Eastern Canal The species composition of Zooplankton community of the canal is rich, indicated by the occurrence of 81 Rotatoria, 9 Cladocera and 1 Copepoda taxa. In most of the year the community is dominated by planktonic species. Moderately polluted conditions in summer are characterized by pollution tolerant, eutrophic species (Anuraeopsis fissa, Brachionus angularis, B. budapestinensis, Epiphanes macruroides, Filinia longiseta, Synchaeta tremula, Trichocerca pusilla, Polyarthra spp). In winter-spring low trophity water indicating species are more frequently encountered. Biomass varies in the range of 0.01 - 2.30 g/m

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. 26. Main Western Canal The species composition of the Zooplankton community of this canal is somewhat poorer, as indicated by 50 Rotatoria and 3 Cladocera taxa. Abundance values and seasonal changes of abundance were similar to the Main Eastern Canal. Biomass was in the same magnitude of order, varied between 0.01 - 0.48 g/m

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. 27. Main Nagykunság Canal Water quality of the Nagykunsági Main Canal is determined by the effluent from the Kisköre reservoir. Species composition of Zooplankton communities is poor. 30 Rotatoria, 11 Cladocera and 1 Copepoda species were registered during the investigations. The plankton indicated in most of the year poor and moderate nutrient supply conditions, similar to non-polluted stagnant or slow flowing waters. It is eutrophic in summer months. Most frequent Rotatoria species were: Hexarthra mira, Synchaeta tremula, Notholca squamula, Pompholyx complanata and Polyarthra spp. From early summer on high number of Cladocera species was characteristic, and the nauplius and copepodite larvae of Copepoda (biomass in July of 1992 was 6.10 g/m

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). Zooplankton biomass varied between 0.03 - 13.96 g/m

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. 28. Rába The upper Hungarian stretch of this river has high flow velocities, abundance of Zooplankton community is therefore low. The abundance values are increasing downsteram, indicating ongoing eutrophication processes. 64 Rotatoria, 12 Cladocera and 6 Copepoda species were recorded at the Hungarian river section, biomass values varied between 0.02 - 1.06 g/m\ Dominant species were Brachionus spp, Euchlanis dilatata Keratella cochlearis, K. quadrata, Trichocerca spp, Bosmina longirostris, Chydorus sphaericus, Moina micrura, Acanthocyclops robustus, Mesocyclops leuckarti, indicating medium and slow flow velocities, with moderate nutrient contents.