Movement and energy expenditure in juvenile green abalone (Haliotis fulgens) exposed to hyperthermia, hypoxia, and both conditions

Abstract

ABSTRACT Green abalone (Haliotis fulgens) experienced severe biomass losses and massive mortality due to short-term marine climatic extremes. We studied green abalone behavior and energy expenditure in response to environmental stress. Acclimatized juveniles were subjected to hyperthermia (26°C), hypoxia (1.0 mg O2 L-1), the combination of both, and control conditions (18°C and oxygen saturation) using an automated system. The movement parameters of organisms were recorded by labeling and filming them, and the respiration rate was measured in hermetic chambers. There were differences in gross and net distance and velocity between the control and the combined stressors. Respiration was raised by hyperthermia, lowered by hypoxia, and further reduced by the combined stressors. All abalone that left the shelter during the night returned by daylight, while hypoxia and hyperthermia reduced this number. Research on environmental stress and movement strategies could lead to a more objective stress proxy.