A comparative study on the temperature dependence of embryogenesis in three coregonids (Coregonus spp.) from Lake Constance

Embroygenesis of the three coregonid forms Blaufelchen, Gangfisch, and Sandfelchen from Lake Constance was observed at five different constant temperatures in a static incubation system. The relationship between temperature and the time to reach 14 developmental stages from fertilization to hatching was established for the three forms. Relative to the total incubation time, pectoral fin flutter and eye movement start earliest in Gangfisch and latest in Blaufelchen. This might allow Gangfisch to tolerate lower oxygen concentrations during the last phase of embryogenesis than Blaufelchen. Developmental rates per day as a function of temperature can be calculated by a power function. A model is presented which permits to predict the time of mass hatching for embryos which are incubated at fluctuating temperatures. The total incubation times for the three coregonids of Lake Constance are short as compared to those of other coregonids. This is interpreted as an adaptation to the specific thermal environment of each coregonid stock which helps to ensure larval survival in the respective habitat.