Plasma osmolarity, glucose concentration and erythrocyte responses of two Antarctic nototheniid fishes to acute and chronic thermal change

• Published in: Journal of Fish Biology
• Main Authors: Lowe, C. J., Davison, W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2005
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1111/j.0022-1112.2005.00775.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.0022-1112.2005.00775.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0022-1112.2005.00775.x

Haematocrit, haemoglobin concentration, plasma osmolarity and plasma glucose concentration of the Antarctic nototheniid fishes Pagothenia borchgrevinki and Trematomus bernacchii were monitored during 24 h periods of exposure to 3 and 6° C. The same haematological variables were also measured in P. borchgrevinki following a 5–6 week period of 4° C acclimation. The first plasma glucose measurements in acutely thermally‐stressed Antarctic nototheniids revealed a delayed hyperglycaemia which related well to the relatively slow stress‐related elevation of plasma cortisol in these species. Plasma osmolarity of both species was unchanged by acute 3° C exposure, but exhibited a delayed and transient increase during acute exposure to 6° C. Haematocrit was unaltered in T. bernacchii during the acute temperature increases but was elevated in the relatively active P. borchgrevinki . Following 5–6 weeks of warm‐acclimation (4° C) the plasma glucose concentration, haematocrit and haemoglobin concentration of P. borchgrevinki were not significantly different from fish at −1° C, but plasma osmolarity decreased toward the level found in temperate‐water teleosts.