Evaluation of Tricaine (MS-222) and Eugenol for Sedation of Peruvian Grunt Anisotremus scapularis.

Anisotremus scapularis is a commercially important species in Peru, where its cultivation and management require technological strategies to minimize stress during aquaculture and fishing practices. Fish handling and transport can induce adverse physiological responses, making anesthetic use a key tool to mitigate these effects and enhance animal welfare. However, information on optimal doses, safety margins, and induction and recovery times of anesthetics in this species remains limited. This study evaluated the effects of eugenol and tricaine (MS-222) on the sedation of A. scapularis juveniles. A total of 450 individuals (9-10 cm total length) were exposed to different concentrations of eugenol and MS-222 (20, 40, 60, 80, and 100 mg/L) via immersion. Induction and recovery times were recorded, determining that the lowest concentrations allowing an optimal induction time (<6 min) and adequate recovery (<16 min) were 20-60 mg/L for eugenol and 80 mg/L for MS-222. These results provide essential information to optimize sedation protocols for A. scapularis juveniles, promoting more efficient handling with minimal impact on fish welfare in production and fishery management systems.