Hypoxia tolerance of European sturgeon (Acipenser sturio L., 1758) young stages at two temperatures - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Journal of Applied Ichthyology Année : 2014

Hypoxia tolerance of European sturgeon (Acipenser sturio L., 1758) young stages at two temperatures

Résumé

European sturgeon sensitivity to oxygen depletion at two different temperatures was evaluated with embryos from fertilization to hatching time that were exposed to 90% O2 saturation (% O2 sat), 50% O2 sat and 30% O2 sat at 20 and 26°C; and three-month-old juveniles (12 cm length, 7.3 g width) exposed to oxygen challenge from 70% O2 sat to 10% O2 sat at 20 and 25°C. Parameters measured included embryonic survival rate (ESR) and hatch rate (HR); in juvéniles the opercular beat frequency (OBF), altered swimming behavior, loss of equilibrium (LOE), and death were recorded. ESR did not differ between oxygen saturation levels for a single temperature but decreased between 20 and 26°C from 60.7 to 21.4% mean survival, respectively. No hatching was observed in embryos exposed to oxygen depletion at 50 and 30% O2 sat, regardless of temperature. The HR was lower at 26°C (15.4% mean) than at 20°C (75.8%) at 90% O2 sat. In embryos, all three oxygen concentrations allowed embryonic survival at the tested temperatures but were insufficient for increased activity such as hatching except at 20°C and 90% O2 sat. In juveniles, OBF peaked at 40% O2 sat at 212 beats per minute at 25°C and at 40–30% O2 sat at 182–183 beats per minute at 20°C. For LOE and death no significant differences were observed with regard to oxygen saturation at 20 and 25°C. Altered swimming behavior appeared at a significantly higher oxygen saturation at 25°C (43.5%) compared to 20°C (34.5%). Anaerobic metabolism was initiated after the OBF peak, which would represent a PO2crit for European sturgeon juveniles under 30 and 40% at 20°C and 25°C, respectively. Temperature increase also adversely affected the threshold of altered swimming behavior, which could be considered as a behavioral indicator of metabolic stress. The probability that the sturgeon embryos are being exposed to harmful temperatures and hypoxic conditions remains a true threat in the Gironde catchment basin.
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Dates et versions

hal-02600625 , version 1 (16-05-2020)

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Citer

Nicolas Delage, J. Cachot, Eric Rochard, Rémy Fraty, Philippe Jatteau. Hypoxia tolerance of European sturgeon (Acipenser sturio L., 1758) young stages at two temperatures. Journal of Applied Ichthyology, 2014, 30 (6), pp.1195-1202. ⟨hal-02600625⟩
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