Kokurewicz, B. and Kowalewski, M. and Witkowski, A. (1980) Influence of constant and variable temperature on the embryonic development of European grayling, Thymallus thymallus (L.). Zoologica Pol., pp. 335-362
| Species | Development state | Trait | Primary Data | Secondary Data |
| Thymallus thymallus | Egg | Incubation time | Time of embryonic development till mass hatching is from 37 days at temperature 3.3°C to 7 days at temperature of 16.7°C. In Lopuszna hatchery hatching takes place after 27-46 days | 36.5 days |
| Thymallus thymallus | Egg | Temperature for incubation | The most favourable temperatures to embryonic development range from 7 to 13°C in conditions of constant temperatures. The embryos developing at temperature lower than 7.3°C are hatching too early in relation to the morphological advancement and are charcaterized by lower vitality. At temperature higher than 13.8°C the survival is low because of lower vitality and increase of abnormally developed larvae in the hatching | 7.0 °C |
| Thymallus thymallus | Egg | Degree-days for incubation | Average evaluation 172 DD. The embryonic development from fertilization till mass hatching is from 122 to 246 DD in laboratories and from 205 to 258 DD in cultures in Lopuszna | 172.0 °C * day |
| Thymallus thymallus | Larvae | Onset of exogeneous feeding | Change to active feeding 4-5 days after hatching | 4.5 °C * day |