Gobio albipinnatus whitefin gudgeon Psammophil. 1.1. 0.7. Barbus barbus barbel. Lithophil. 4.2. 3.8. 4.5. Albumus alburnus bleak. Phytolithophil. 18.2 35.6. 21.5.
202
Large Rivers Vol. 12, No. 2-4 Arch. Hydrobiol. SuppI.135/2-4, p.187-202, Februar 2001
P.Jurajda et al.
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Comparison of 0+ fish communities between regulated-channelized and floodplain stretches of the River Morava P.Jurajda 1, M. Reichard2, E. Hohausová 1 and J. Cerný3 With 5 figures and 2 tables in the text
- Forschungs-
inst. WWF Ósterreich 5: 180 pp. TuRNER, T. F, TREXLER,J. C., MILLER, G. L. & TOYER, K. E. (1994): Temporal and spatial dynamics of larval and juvenile tish abundance in a temperate floodplain river. Copeia 1994: 174-183. WITKOWSKI,A. (1984): Stmcture of communities and biomass of ichtyofauna in the Biebr-
za River, its old river beds and a.ffluents.- Polish Eco!' Studies 10: 447-474. Received: April 1998; accepted: January 1999.
Abstract:
Recmitment
of 0+ tishes in two lowland stretches
(regulated-channelized
and
floodplain) of the River Morava (Danube basin) was assessed by electrotishing, using the point abundance sampling strategy. Both stretches originally meandered with large floodplains, howevér, the upper stretch has been extensively channelized resulting in the cessation offlood events and 5 weirs now interrupt the flow ofthe river. During two years (1995-96), 49 and 37 sites were sampled, respectively, during late summer and 0+ tish communities were evaluated and used to describe reproductive efficiency and recmitment. Changes in the character of spawning sites and nursery areas, after channelization and regulation have affected the 0+ tish community. In both years the total number of 0+ tish species was higher in the floodplain stretch of the river (22 and 16 resp.) compared with the regulated-channelized stretch (18 and 13 resp.). However, the average species richness in all sarnpled sites was signiticantly
higher in the regulated-channelized
stretch during low discharge, although 110
signiticaIlt difference was apparent during high discharge. The major component of 0+ tish cQmmunity in the regulated-channelized stretch comprised of bitterling, bleak, chub md roach in both years. The recmitment of phytophilous species was strongly limited in this stretch of the river at all times, and during high discharge species richness and density of 0+ tish signiticantly decreased. In the floodplain stretch, bleak and white brearn accounted for more than 50 % uf the 0+ tish community during low discharge. During the higher SpriIlg
.
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