Víztudományi és Vízbiztonsági Nemzeti Laboratórium(RRF-2.3.1-21-2022-00008) Támogató:
NKFIH
This study assessed the functional effectiveness in terms of passage proportion of
three fishways, one nature‐like bypass, one partly nature‐like bypass and partly technical
pool‐type and one completely technical, on the Pinka Stream and Rába River in Western
Hungary. Radio frequency identification with passive integrated transponder tagging
was used to collect data on the upstream passage. A total of 2976 tagged individuals
were included in the study; 2863 individuals were either barbel ( Barbus barbus ),
nase ( Chondrostoma nasus ) or chub ( Squalius cephalus ), which were chosen as model
species, and 113 individuals belonged to four other species. There were 540 individuals
of the model species and 18 individuals of the other species detected while successfully
ascending one of the fishways. The time‐to‐event (survival) analysis of the data of
the model species revealed significant species‐specific differences in passage probability
between the fishways. The passage probabilities of the barbel were the highest, and
those of the nase were the lowest at all three fishways. The findings demonstrate
that single‐species evaluations can lead to incorrect conclusions on fishway effectiveness.
Technical fishways can be as effective as nature‐like ones, and hybrid solutions (technical
fishways combined with nature‐like bypasses) can function as well. The limitations
of the study and recommendations for further evaluations are also discussed.