Hatching of Coregonus albula and C. lavaretus embryos at different stages of development

Hatching in Coregoninae embryos is not closely connected with a determined stage of embryonic development. Electrical stimulation (AC) induced precocious hatching, and incubation at low temperature caused delay of hatching compared to controls. Embryos hatched precociously had shorter bodies and larger yolksacs than those whose hatching was normal or delayed. This was accompanied by respective changes in duration of the eleutheroembryonic phase (DEP) - in Coregonus lavaretus DEP decreased from 7 days in embryos hatched precociously to 0 days in embryos from delayed hatching.