Location: Warmwater Aquaculture Research UnitTitle: Metabolic and locomotor responses of juvenile paddlefish Polyodon spathula to hypoxia and temperature Author
Submitted to: Comparative Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2014
Publication Date: 2/10/2014
Citation: Aboagye, D.L., Allen, P.J. 2014. Metabolic and locomotor responses of juvenile paddlefish Polyodon spathula to hypoxia and temperature. Comparative Biochemistry and Physiology. 169:51-59. Interpretive Summary: American paddlefish are an increasingly important aquaculture species, for both meat and caviar production, and an important conservation aquaculture species. In order to understand minimum dissolved oxygen concentrations for culture, hypoxia tolerance and physiological performance were tested at two temperatures. Juvenile paddlefish require a minimum of 2 mg/L dissolved oxygen to survive, but require > 4.7 mg/L dissolved oxygen to prevent anaerobic metabolic compensation.
Technical Abstract: Hypoxia is an increasing problem in the natural habitats that the paddlefish (Polyodon spathula) has historically inhabited, and a potential problem in managed culture conditions. However, the effects of hypoxia on paddlefish are not well understood. In order to understand the effects of hypoxia on juvenile paddlefish, acute hypoxia tolerance, aerobic metabolic rates and swimming capabilities were measured under normoxic (PO2 = 140–155 mm Hg) and hypoxic (PO2 = 62–70 mm Hg) conditions at 18 °C and 26 °C. The results showed that paddlefish acclimated to 18 °C and 26 °C had routine metabolic rates of 211 mg/kg/h and 294 mg/kg/h, respectively, with a corresponding Q10 of 1.5. At 18 °C and 26 °C, paddlefish had a critical partial pressure of oxygen (PO2crit) of 74 mm Hg and 89 mm Hg, respectively. Paddlefish had a lethal oxygen threshold of 31.0 mm Hg and 37.0 mmHg at 18 °C and 26 °C, respectively. Further, paddlefish exhibited a reduction in swimming capability when exposed to hypoxia with a 24% and 41% decrease in Ucrit at 18 °C and 26 °C, respectively. Therefore, paddlefish are relatively sensitive to hypoxia, and at temperatures from 18 to 26 °C require a dissolved oxygen concentration =4.7 mg/L to maintain basal aerobic metabolism and N2.0 mg/L to survive under acute hypoxia.