The Effects of Noise on the Juvenile Life Stage of Crustaceans: Behavioral, Cellular, and Molecular Responses in <i>Procambarus clarkii</i>

Underwater noise from human activities is an increasing concern due to its potential ecological impacts. While knowledge on its effects on aquatic species is growing, responses of juvenile invertebrates remain poorly understood. This study investigated behavioral, cellular, and molecular responses to noise (1-20 kHz linear sweep) in juvenile Procambarus clarkii (Girard, 1852). Behavioral parameters (including movement, interactions, feeding, and tail flips) were recorded using overhead video and analyzed with BORIS software. Cellular assays measured esterase, alkaline phosphatase, glucose, total protein (TP), peroxidase, superoxide dismutase (SOD), and cytotoxicity. Additionally, gene expression of crustin, prophenoloxidase (proPO), Heat shock protein 70 (HSP70), Heat shock protein 90 (HSP90), caspase, SOD and catalase (CAT) was assessed via real-time PCR. Specimens exposed to underwater noise exhibited increased interactions and feeding, but no significant changes in movement were observed. Results of cellular analysis revealed elevated protein content, hydrolase, and antioxidant activity, while glucose and cytotoxicity levels decreased. Molecular analyses showed upregulation of immune and stress-related genes (crustin, proPO, HSP70, HSP90, and caspase) and downregulation of SOD and CAT, indicating potential oxidative stress. These findings suggest that even early life stages of invertebrates are sensitive to underwater noise disturbance, affecting the specimens at multiple interconnected levels.