Opercular beat: A non-invasive and rapid method to detect stress in seahorses

Abstract

ABSTRACT Seahorses are commonly used in the aquarium trade and in seahorse-watching ecotourism in Brazil. Their manipulation and transportation may lead to significant stress, compromising their health. Assessing stress response during manipulation is difficult. Thus, the aim of the present study was to identify respiration patterns for these animals, providing baseline data for a health and well-being protocol to be applied during seahorse management. We conducted experiments in captivity and in the wild to evaluate transportation and handling as potential stressors. Significant differences between opercular beat after manipulation and recovery was observed in captivity and in the wild. Seahorses displayed a base opercular beat around 30/min in the wild and 45/min in captivity, increasing to 66 beats/min after manipulation in the wild and 64/min in captivity. No difference between sex or size was noticed. Opercular beat in captivity remained higher than in the wild 24 h after manipulation, suggesting that captivity protocols should include acclimation longer than 24 h.