Marine Biodiversity and Ecosystems

Temperature and cardiovascular physiology of Antarctic fish

Principal Investigator: Bill Davison
Organisation: University of Canterbury

What we do: The central theme of this project is the cardiovascular and respiratory physiology of Antarctic notothenoid fish, particularly as it relates to small, sub-lethal increases in temperature. Parameters to be examined include oxygen uptake at the gills, oxygen consumption by the fish, the presence of hypoxia and its effects on the heart, and the ability of the heart itself to provide the driving force for blood flow.

Why we do it: Antarctic fish are extremely stenothermal, having upper lethal limits only a few degrees above their habitat temperature. Temperature changes are already having effects on the distributions of animals in the Southern Ocean, yet there is little information available on the effects of increased temperatures in their physiology.  Determination of the combination of physiological variables will allow insights into the role of the cardiovascular system in determining upper thermal limits.

Some things we've found so far: Swimming ability has been shown to improve with acclimation to the higher temperatures. Time needed for this acclimation may be as little as a week.

Recent Publications:
Lowe, C.J. and Davison, W. Plasma osmolarity, glucose concentration and erythrocyte responses of two Antarctic nototheniid fishes to acute and chronic thermal change. Journal of Fish Biology 67: 752-766. 2005.

Lowe, C.J., Seebacher, F., Davison, W. Thermal sensitivity of heart rate and insensitivity of blood pressure in the Antarctic nototheniid Pagothenia borchgrevinki. Journal of comparative physiology B 175: 97-105. 2005.

Seebacher et. al. A falsification of the thermal specialization paradigm: compensation for elevated temperatures in Antarctic fishes. Biology Letters 1: 151-154. 2005.