TEMPERATURE DEPENDENCE OF BREATHING RATE IN CARP

¹ Agricultural Institute, University of Louvain (Belgium)

1. The dependence of the frequencies of respiratory movements upon temperature has been studied in Cyprinus carpio L.

2. The degree of dependence of these frequencies upon temperatures is primarily determined by the size of the fishes. Large fishes are highly, small fishes only slightly, dependent.

3. Small fishes are characterized by a broad homeostatic zone of independence of the breathing frequency on temperatures. This homeostatic zone disappears in large fishes. The upper lethal temperatures decrease concomitantly with the disappearance of the homeostatic zones.

4. Individual variants, as to the degree of homeostasis and as to the adaptive temperature ranges, can be detected by the method presented. It can be used for studying genetic determination of these characteristics.

5. A survey of the data in the literature allows one to distinguish poikilotherms with progressive and with regressive ontogenies, with respect to homeostatic behavior.