Cardiac and behavioural responses to hypoxia and warming in free-swimming gilthead seabream, Sparus aurata

Type Article
Date 2021-07
Language English
Author(s) Mignucci AlexandreORCID1, Bourjea JeromeORCID1, Forget FabienORCID5, Allal Hossein2, Dutto GilbertORCID3, Gasset EricORCID3, McKenzie DavidORCID4
Affiliation(s) 1 : MARBEC, Université de Montpelier, CNRS, IRD, Ifremer, 34200 Sète, France
2 : CHU de Montpellier, Service Chirurgie Pédiatrique, 34000 Montpellier, France
3 : MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 34250, Palavas-les-Flots, France
4 : MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 34095 Montpellier, France
5 : MARBEC, Université de Montpelier, CNRS, IRD, Ifremer, 34200 Sète, France
Source Journal Of Experimental Biology (0022-0949) (The Company of Biologists), 2021-07 , Vol. 224 , N. 14 , P. jeb242397 (?)
DOI 10.1242/jeb.242397
WOS© Times Cited 1
Keyword(s) Heart rate, Acceleration, Biologging, Respirometry, Star-Oddi, Confinement, Oxygen saturation, Teleost
Abstract

Gilthead seabream were equipped with intraperitoneal biologging tags to investigate cardiac responses to hypoxia and warming, comparing when fish were either swimming freely in a tank with conspecifics or confined to individual respirometers. After tag implantation under anaesthesia, heart rate (fH) required 60 h to recover to a stable value in a holding tank. Subsequently, when undisturbed under control conditions (normoxia, 21°C), mean fH was always significantly lower in the tank than in the respirometers. In progressive hypoxia (100% to 15% oxygen saturation), mean fH in the tank was significantly lower than in the respirometers at oxygen levels down to 40%, with significant bradycardia in both holding conditions below this level. Simultaneous logging of tri-axial body acceleration revealed that spontaneous activity, inferred as the variance of external acceleration (VARm), was low and invariant in hypoxia. Warming (21 to 31°C) caused progressive tachycardia with no differences in fH between holding conditions. Mean VARm was, however, significantly higher in the tank during warming, with a positive relationship between VARm and fH across all temperatures. Therefore, spontaneous activity contributed to raising fH of fish in the tank during warming. Mean fH in respirometers had a highly significant linear relationship with mean rates of oxygen uptake, considering data from hypoxia and warming together. The high fH of confined seabream indicates that respirometry techniques may bias estimates of metabolic traits in some fishes, and that biologging on free-swimming fish will provide more reliable insight into cardiac and behavioural responses to environmental stressors by fish in their natural environment.

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Mignucci Alexandre, Bourjea Jerome, Forget Fabien, Allal Hossein, Dutto Gilbert, Gasset Eric, McKenzie David (2021). Cardiac and behavioural responses to hypoxia and warming in free-swimming gilthead seabream, Sparus aurata. Journal Of Experimental Biology, 224(14), jeb242397 (?). Publisher's official version : https://doi.org/10.1242/jeb.242397 , Open Access version : https://archimer.ifremer.fr/doc/00710/82168/