FISH MIGRATION AND FISH RAMP ASSESSMENT AT A GAUGING STATION ON A MEDITERRANEAN RIVER (CATALONIA, NE IBERIAN PENINSULA)
In May and October 2013, an in situ assessment of the fish ramp at the gauging station on the Fluvià River at Olot was performed, using different techniques to estimate the fish ramp’s effectiveness. This fish ramp is one of the first in Catalonia (NE Iberian Peninsula) that follows international guidelines for fish passes and especially for fish ramps.
The fish ramp allowed passage of all native cyprinid species from this river. The crossing rates were higher in May (average of 7.9 ind./day for Barbus meridionalis and 3.8 ind./day for Squalius laietanus), a month associated with their spawning period, than in October (average of 4.6 ind./day for B. meridionalis and 1.0 ind./day for S. laietanus).
Pending complementary year-round samplings for several annual periods, the results show that the spawning period seems to be the primary driver of upstream fish migration, which is also influenced by a decrease in river flow just after a peak flow, a minimum water temperature value and less bright lunar phases.