Temperature and size-dependency of lumpfish (Cyclopterus lumpus) oxygen requirement and tolerance

• Published in: Aquaculture Vol. 548; p. 737576
• Main Authors: Remen, Mette, Nes, Armand Moe, Hangstad, Thor Arne, Geraudie, Perrine, Reynolds, Patrick, Urskog, Tonje Cecilie, Hanssen, Anna, Stefansson, Sigurd Olav, Imsland, Albert Kjartan Dagbjartarson
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-02-2022
• Subjects: Aerobic scope; Hyperoxia; Hypoxia; Lumpfish; Metabolism; Stress; Aerobic scope; Lumpfish; Hypoxia; Metabolism; Hyperoxia; Stress
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2021.737576

Lumpfish are currently produced and utilized as cleaner fish, to control sea lice infestation rates in salmon net pens, but information on environmental requirements is still limited. This study aimed to determine the zone of environmental hypoxia for two relevant fish sizes (15 and 60 g) and temperatures (5 and 12 °C), using intermittent flow respirometry (referred to as 15:5, 15:12, 60:5, 60:12), and to investigate parameters of stress in response to acute changes in dissolved oxygen (DO, % air saturation) from normoxia to 47, 63, 98 (control), 148 and 194% O2 at 10 °C. The standard and maximal metabolic rates (SMR and MMR) were measured in normoxia (n = 8), and MMR was measured at 5–6 DO levels ranging from 20−160% O2 (n = 8 per DO) to define the upper and lower boundaries of the hypoxic zone (DOlim and DOcrit). SMR, MMR and the aerobic metabolic scope (AS) increased with temperature and decreased with fish size. Similar effects of temperature and size were found on DOcrit – DOlim ranges: 20–55 (15:5), 35–147 (15:12), 21–53 (60:5) and 22–89 (60:12) % O2 air saturation. Results from acute exposure tests resulted in elevated cortisol levels at 63 and 47% O2, although not statistically significant at 47% O2. Other parameters of hypoxic or hyperoxic stress (lactate, pH, osmolality, lipid peroxidation rates, catalase activity) were not affected. Results from the present study suggest that lumpfish may experience oxygen levels in sea cages that restricts metabolism, performance and induce hypoxic stress.
•The zone of env. Hypoxia (ZEH) was studied in 15 and 60 g lumpfish at 5 and 12 °C.•Interactive effects of temp. and size on ZEH boundaries (DOcrit/DOlim) were found.•DOcrit ranged from 20 to 35% O2, DOlim ranged from 53 to 147% O2.•Increased plasma cortisol was observed in moderate, acute hypoxia (63% O2).•Oxidative stress was not observed in moderate, acute hyperoxia (148 and 194% O2).