Behavioural and biochemical stress responses of Cherax quadricarinatus after exposure to acoustic signal in tank

Abstract

Anthropogenic sound is recognized as a major environmental stressor that, in the long term, can have negative consequences on species. In recent years, there has been growing attention to the potential negative impact of noise pollution on species, with great concern about the significance of impacts on aquatic animal life. This study examined the effects of acoustic stress on the behavior and biochemical parameters of the freshwater shrimp Cherax quadricarinatus. The experiment was conducted in a tank equipped with an audio and video recording system using ten groups (five control and five test) of three adult shrimp (30 animals in total). Animals in the test group were exposed to acoustic signals [a linear sweep from 1 to 20 kHz lasting 1 s, with a sound pressure level between 138 and 157 dBrms (re 1lParms)] for 45 minutes. Behavioral parameters such as, total acoustic signals emitted, movement velocity, angular velocity, distance moved, no. of fights, encounters, tail flip and biochemical parameters such as pH, osmolarity, protein concentration and enzyme activities (alkaline phosphatase, esterase and peroxidase) were evaluated. Exposure to the acoustic signal produced significant changes on the specie's total acoustic signals emitted and no. of fights. Enzyme activities show significant changes, with significantly lower values in stressed animals. These results suggest that high-frequency stimuli induce both a behavioural and physiological response, thus suggesting that acoustic stress may have an effect on the species.