Osmo-respiratory compromise in the mosshead sculpin (Clinocottus globiceps): effects of temperature, hypoxia, and re-oxygenation on rates of diffusive water flux and oxygen uptake

• Published in: Fish physiology and biochemistry 2023-10, Vol.49 (5), p.853-866
• Main Authors: Onukwufor, John O., Somo, Derek A., Richards, Jeffrey G., Wood, Chris M.
• Format: Article
• Language: English
• Subjects: air; Animal Anatomy; Animal Biochemistry; Animal Physiology; Biomedical and Life Sciences; Clinocottus globiceps; Cottidae; Epithelium; fish; Fluctuations; Freshwater & Marine Ecology; Histology; Hypoxia; Life Sciences; Marine fishes; Morphology; Oligocottus maculosus; Oxygen; Oxygen consumption; Oxygen tension; Oxygen uptake; Oxygenation; Permeability; Respiration; Saturation; temperature; Temperature effects; Tide pools; Uptake; Water; Zoology
• ISSN: 0920-1742; 1573-5168
• DOI: 10.1007/s10695-023-01226-0

In nature, mosshead sculpins ( Clinocottus globiceps ) are challenged by fluctuations in temperature and oxygen levels in their environment. However, it is unclear how mosshead sculpins modulate the permeability of their branchial epithelia to water and O 2 in response to temperature or hypoxia stress. Acute decrease in temperature from 13 to 6 o C reduced diffusive water flux rate by 22% and ṀO 2 by 51%, whereas acute increase in temperature from 13 to 25 o C increased diffusive water flux rate by 217% and ṀO 2 by 140%, yielding overall Q 10 values of 2.08 and 2.47 respectively. Acute reductions in oxygen tension from >95% to 20% or 10% air saturation did not impact diffusive water flux rates, however, ṀO 2 was reduced significantly by 36% and 65% respectively. During 1-h or 3-h recovery periods diffusive water flux rates were depressed while ṀO 2 exhibited overshoots beyond the normoxic control level. Many responses differed from those seen in our parallel earlier study on the tidepool sculpin, a cottid with similar hypoxia tolerance but much smaller gill area that occupies a similar environment. Overall, our data suggest that during temperature stress, diffusive water flux rates and ṀO 2 follow the traditional osmo-respiratory compromise pattern, but during hypoxia and re-oxygenation stress, diffusive water flux rates are decoupled from ṀO 2 .