Evaluation of the Cortisol Stress Response in a Marine Perciform Fish, the San Pedro Oplegnathus insignis

Abstract

The San Pedro (also known as the Pacific beakfish) Oplegnathus insignis is a species of perciform fish found in the eastern Pacific Ocean. In northern Chile, San Pedro are an important food fish currently being evaluated for aquaculture. The purpose of this study was to conduct an initial evaluation of the cortisol stress response in captive-bred San Pedro. The fish were subjected to confinement stress by crowding them into a low volume of water (231 kg/m³) for 90 min. Blood was collected over time for the determination of plasma cortisol. Confinement resulted in a significant increase in plasma cortisol, from a resting concentration of 24.9 ng/mL to 120.7 ng/mL after 10 min into the stress experience. After 20 and 60 min of stress, cortisol concentrations plateaued at 225.3 ng/mL and 243.7 ng/mL, respectively, followed by a decrease to 56.1 ng/mL by 90 min. These results indicate a rapid and robust cortisol stress response in this species. This is the first evaluation of the San Pedro stress response, and these data will serve as the baseline for future evaluations of San Pedro stress physiology and the development of aquaculture techniques suitable for this species.

Received December 9, 2011; accepted January 30, 2012

ACKNOWLEDGMENTS

We thank the INNOVA-CHILE COD 06FCO1IBC-118 project for funding this research. We are also grateful to all CORDUNAP people who helped carry out this project.