Exercise metabolism in two species of cod in arctic waters

Abstract

The northern range of Atlantic cod (Gadus morhua), overlaps the southern range of the Greenland cod (Gadus ogac), in the coastal waters of Western Greenland. The availability of a temperate water species (G. morhua) in the same area and oceanographic conditions as a polar species (G. ogac) presented us with the ideal circumstances to test the hypothesis of metabolic cold adaptation (MCA) since many of the problems associated with MCA studies (adaptation of the animals beyond their normal temperature range or mathematical extrapolation of data to common temperatures) could thus be avoided. We therefore used a swim tunnel to measure oxygen consumption in fish at 4°C over a range of swimming speeds and following exhaustion, monitored the size of the oxygen debt and time of oxygen debt repayment. There were no significant differences in standard (60–72 mg O2 kg−1· hr−1), routine (76 mg O2 kg−1·hr−1), active (137mg O2 kg−1·hr−1), or maximal (157 mg O2 kg−1·hr−1) metabolic rate, metabolic scope (2.5) or critical swimming speed (2.2 BL·s−1) between the two species. Following exhaustive swimming, however, the half-time for oxygen debt repayment in G. ogac (43 min) was almost twice that of G. morhua (25 min). Despite its circumpolar distribution, therefore, there was no evidence of MCA in G. ogac.

DOI: 10.1007/BF00240271

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Cite this paper

@article{Bushnell2004ExerciseMI, title={Exercise metabolism in two species of cod in arctic waters}, author={Peter G. Bushnell and John Fleng Steffensen and Henrik Schurmann and Dr Rodney Jones}, journal={Polar Biology}, year={2004}, volume={14}, pages={43-48} }