The use of ultrasonication for cyanobacterial control
in freshwater bodies has become increasingly popular
during the last decades despite controversial efficiency on
large scale application. Apart from that, little information is
currently available regarding ultrasound toxicity potential towards
non-target species. This work was designed to address
this issue in the common carp using a low-power (7–9 W
output) and dual-frequency (23 and 46 kHz) anticyanobacterial
ultrasound device. Results showed that carps
were unaffected by ultrasound exposure when exposed in
floating cages in fish ponds over a 30-day period. The experiment
duration was the main factor influencing all measured
biological parameters in exposed and non-exposed organisms.
Indeed, it was positively associated with an increase in fish
condition factor. Cortisol level also tended to slightly increase
over the number of days of experiment but its variation did not
enable to sort out any ultrasound exposure-related stress.
Moreover, an overall diminution along the experimental period
of the expression level of a set of biomarkers could be
reported, encompassing cellular antioxidant enzyme activities
such as superoxide dismutase (SOD), glutathione peroxydase
(GPx), catalase and glutathione S-transferase (GST), and lactate
dehydrogenase activity. Subtle changes in these biomarkers
were dependent of the type of enzyme activity and
especially of the origin of fish (i.e., sampled pond) regardless
of the presence of ultrasound equipment, reflecting thereby
fish adaptation to local environmental conditions in each
pond. In conclusion, this study does not provide indication
that ultrasonication in the aforementioned conditions affects
the welfare and physiological homeostasis of carps.