Annoying noise: effect of anthropogenic underwater noise on movement and feeding performance in the red cherry shrimp Neocaridina davidi
Acoustic pollution in aquatic environments has increased dramatically, with adverse effects on many organisms. Benthic organisms, including many invertebrates, can sense underwater sounds, yet the responses they trigger in these organisms have received little attention. This study investigates the impact of underwater sound on the behaviour of the red cherry shrimp Neocaridina davidi as a model of freshwater decapod. The effect of underwater sound exposure on the movement behaviour and feeding performance of individual shrimps was assessed. Movement speed decreased significantly upon opening the divider in both the sound and control treatments. However, there were no significant changes in total minutes between the control and sound treatments, implying no sound-related initial changes for releasing movement. The spatial distribution of shrimps in response to the sound treatment showed significant changes; shrimps spent more time at the farthest point from the sound source. The time to find the food source (latency) also increased in the sound treatment compared to the control. Moreover, in terms of the number of successes and failures in finding the food source in the control treatment, significantly more shrimps succeeded in finding the food source. Besides, the number of revisits to the food source decreased in sound treatment compared to control and more shrimps were significantly distracted in sound treatment. Our study highlights the crustaceans ability to receive human-made sound. Thus, they are prone to the impacts of anthropogenic sound, causing negative impacts on their movement-swimming activities, and feeding behaviour and exposing them to potential predator threats. Affecting foraging performance in this gregarious species may have detrimental impacts on their reproductive success and, subsequently unexpected fitness consequences.