Macroinvertebrate and fish community
While Chironomidae were the most abundant taxa in the invertebrates
samples of sites located upstream of the dam, Bivalvia and Gastropoda
dominated the community composition upstream of the dam (Appendix 1).
However, ANOSIM revealed that the composition of community structure of
benthic invertebrates upstream and downstream of the dam was not
significantly different. Total abundance was significantly higher at
locations downstream of the dam (Z = 3.86, P = 0.0495; 5945 individuals
m-2 ± 2106, mean ± SD) compared to locations upstream
of the dam (982 individuals m-2 ± 1100; Figure 2).
We caught 20 fish species in total (Appendix 2). The three most abundant
fish species were roach Rutilus rutilus , bleak, and perch (37.6
%, 17.5 %, and 15.7 % of total abundance, respectively; Appendix 2).
ANOSIM indicated that the fish community composition upstream and
downstream of the dam was not significantly different, neither when
accounting abundances (i.e., CPUE), nor biomass data (i.e., BPUE).
However, total CPUE of all fishes was significantly higher in locations
downstream of the dam (Z = 3.86, P = 0.0495; 158 individuals 1000
m-1 ± 49) compared to locations upstream of the dam
(60 individuals 1000 m-1 ± 35; Figure 3), but BPUE was
not significantly higher.