Inhibiting Common Carp Movement with a Bubble Curtain

Bubble curtains generate distinct hydrodynamic and acoustic fields that may be exploited to deter passage of invasive fish species. This technology is particularly useful at sites where other barrier technologies are either too expensive or do not function.  In this study, the invasive common carp, Cyprinus carpio L., was used as a model species to test the efficacy of the bubble curtain to inhibit movement, because this species, like many other ostariophysians, has a well developed sense of hearing.  Behavioral laboratory trials revealed a 72% and 80% reduction in the number of times common carp crossed the bubble curtain in up- and down-stream directions, respectively.  Sound appeared to be the dominant stimulus for common carp, as complementary acoustic measurements showed that a simple bubble curtain generated a sound field with a maximum sound pressure level of 120-130dB (re 1µPa) at 150Hz, well above the minimum hearing threshold for common carp.  Hydrodynamic measurements were also obtained to characterize the resultant fluid flow fields.  Based on the behavioral laboratory trials, a full scale bubble curtain prototype was developed and installed in the field.  The preliminary field results and the bubble curtain’s role as an effective watershed management tool will be discussed.

This research was funded by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).