EMBRYONIC-DEVELOPMENT OF BROWN TROUT (SALMO-TRUTTA M FARIO)

The early development of brown trout (Salmao trutta m. fario) was studied under conditions of artificial incubation from the fertilisation up tb the hatching of embryos (12.0-13.8 mm in length, 15 mg in weight), which began on the 116th-138th days of incubation when the water temperature in the hatchery rose over 5 degrees C (the average water temperature during incubation was 1.6-1.7 degrees C). Basic morphometrical and timing data are presented with individual developmental steps (I-IX). Only after 54 hours from the beginning of incubation, in cell stage 8-16, could fertilised eggs be distinguished from non-fertilised eggs.