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

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

29. Repce Species composition of Zooplankton community is poor with low abundance. Only 32 Rotatoria, 7 Cladocera and 3 Copepoda species were found, these are quite common in Hungarian waters. Biomass values were in the range of 0.07 - 0.23 g/m'

. High flow velocities are unfavorable for the formation of larger Zooplankton populations. 30. Rábca 37 Rotatoria, 9 Cladocera and 3 Copepoda taxa were found in this river. In all cases samples were dominated by Rotatoria. Biomass value is similar to Repce, varied between 0.06 - 1.12 g/m . Some rare rotifers (Beauchampiella eudactylota, Euchlanis oropha, Lecane ichthyura, Lecane stenroosi) were also recorded here. 31. Marcal The composition and abundance of the Zooplankton community of the upper and lower stretch of the river showed marked differences. Altogether 37 Rotatoria 8 Cladocera and 2 Copepoda species were found. As a result of the benthic eutrophication in the upper stretch, the biomass is small (0.02 - 0.38 g/m

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), indicating good water quality. Many rare species were recorded here (Cephalodella ventripes, Euchlanis parva, Lecane hamata, Mytilina ventralis brevispina), which are living in macrophyte vegetation. Near to the confluence, biomass increased (0.06 - 8.93 g/m

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), indicating increasing eutrophication. High numbers were due to eutrophic rotifers. 32. Lajta 31 Rotatoria, 3 Cladocera and 1 Copepoda species were found at the Mosonmagyaróvár sampling site of the fast flowing river. Species composition and biomass value of the Zooplankton community indicate good water quality. As a result of hydraulic conditions no large populations were formed (biomass varied between 0.09 - 0.92 g/m). Some rare Rotatoria species were also recorded here: Dicranopohorus epipharis, Epiphanes pelagica, Itura aurita, Parodieranophorus hudsoni. 33. Concó The water of the creek is very rich in organic matter. Most of Rotatoria and Crustacea taxa are characteristic to polluted and highly trophic waters. Most of the populations inhabit the surface of the sediment and macrophyte vegetation. Species composition is poor, only 24 Rotatoria, 5 Cladocera and 6 Copepoda species were found. Large biomass values (0.41 11.69 g/m

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; average 3.21 g/m

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) are supporting the above argumentation. 34. Általér This stream was practically divided into three section by water management activities. Zooplankton of the stretch upstream of the cooling lakes is characterized by only 29 Rotatoria, 4 Cladocera and 3 Copepoda species. The biomass is generally small, but as a result of extreme