ISSN:
1432-136X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Eggs ofSalvelinus alpinus were maintained from the eyed stage to several weeks after hatching at two temperatures (4 and 8 °C) and three levels of oxygen concentration (20% of air saturation at 4 °C, 30% at 8 °C, 50% and 100%). Mortality was low under all conditions except after hatching at 8 °C and 30% air saturation. 2. Weight-specific oxygen consumption increased in the growing embryos under all conditions. The total amount of oxygen consumed by the embryos up to peak hatching time is directly dependent on the oxygen concentration of the medium but is nearly independent of temperature. 3. The average weight at which an embryo hatches depends directly onP O 2, but is only little influenced by temperature. This is at variance with observations on other salmonids. 4. The ‘factorial aerobic scope for activity’ after hatching is highest ( $$\bar x$$ up to 5.2) at 8 °C and 50–100% air saturation, and lowest (1.6) at 4 °C and 20% air saturation. 5. The large effect of temperature between 4 and 8°C on the rate of metabolism of the hatched larvae may be explained by the stimulating effect of the higher temperature on swimming activity. Oxygen concentration in the medium has no apparent effect on the temperature sensitivity of metabolism. 6. If compared with the respiratory rate of adultS. alpinus as measured by Holeton (1973) the respiratory rates of the embryos remained below the size corrected basal rate of fish living at 2–6 °C. There is no indication of ‘cold acclimation’ of the metabolism ofS. alpinus. 7. The slopes of the functional relationship between rate of oxygen consumption andP O 2 are not influenced by temperature. 8. Production efficiency of the embryo is only slightly affected byP O 2 and temperature. On the other hand, the production efficiencies of the swimming larvae at the yolk sac stage are higher at 4 than at 8 °C and show an unexpected maximum at 50% oxygen concentration, particularly at the higher temperature. 9. A hypothesis is presented which relates the experimental findings to the ecology and behaviour ofS. alpinus, suggesting various adaptive responses of the species to low oxygen concentration and temperature increase in the medium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00690007
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