Stenotherms at sub-zero temperatures: thermal dependence of swimming performance in Antarctic fish
Wilson, R.S.; Franklin, C.E.; Davison, W.; Kraft, P. (2001). Stenotherms at sub-zero temperatures: thermal dependence of swimming performance in Antarctic fish. J. Comp. Physiol. (B Biochem. Syst. Environ. Physiol.) 171(4): 263-269. dx.doi.org/10.1007/s003600000172
In: Journal of comparative physiology. Part B. Biochemical, systemic, and environmental physiology. Springer: Heidelberg; Berlin. ISSN 0174-1578; e-ISSN 1432-136X, more
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thermal sensitivity; specialist; trade-off; acclimation; phenotypicplasticity |
| Authors | | Top |
- Wilson, R.S.
- Franklin, C.E.
- Davison, W.
- Kraft, P.
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| Abstract |
We examined the burst swimming performance of two Antarctic fishes,Trematomus bernacchii andT. centronotus, at five temperatures between –1°C and 10°C. As Antarctic fishes are considered one of the most cold specialised and stenothermal of all ectotherms, we predicted they would possess a narrow thermal performance breadth for burst swimming and a correlative decrease in performance at high temperatures. Burst swimming was assessed by videotaping swimming sequences with a 50-Hz video camera and analysing the sequences frame-by-frame to determine maximum velocity, the distance moved throughout the initial 200 ms, and the time taken to reach maximum velocity. In contrast to our prediction, we found both species possessed a wide thermal performance breadth for burst swimming. Although maximum swimming velocity for bothT. bernacchii andT. centronotus was significantly highest at 6°C, maximum velocity at all other test temperatures was less than 20% lower. Thus, it appears that specialisation to a highly stable and cold environment is not necessarily associated with a narrow thermal performance breadth for burst swimming in Antarctic fish. We also examined the ability of the Antarctic fishPagothenia borchgrevinki to acclimate their burst-swimming performance to different temperatures. We exposedP. borchgrevinki to either –1°C or 4°C for 4 weeks and tested their burst-swimming performance at four temperatures between –1°C and 10°C. Burst-swimming performance ofPagothenia borchgrevinki was unaffected by exposure to either –1°C or 4°C for 4 weeks. Maximum swimming velocity of both acclimation groups was thermally independent over the total temperature range of –1°C to 10°C. Therefore, the loss of any capacity to restructure the phenotype and an inability to thermally acclimate swimming performance appears to be associated with inhabiting a highly stable thermal environment. |
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