Study of morphogenesis and allometric growth pattern of Sterlet, Acipenser ruthenus, during early larval development

Allometric growth pattern of Sterlet (Acipenser ruthenus) was studied during larval development from hatching up to 50 days post hatching. For this experiment, in total 180 specimens were sampled and their left side photographed using a digital camera. Morphometric parameters of this study obtained from 2D pictures of specimens using the software ImageJ and allometric growth pattern was calculated as a power function of total length using non-transformed data: Y=axb. Results revealed that morphogenesis and differentiation during early ontogeny i.e. prelarval stages is more intense than larval stage. The allometric growth pattern of the tail length, head length and head width were positive allometric up to 14, 17 and 20 dph, respectively. This can be as result of vital functions importance including swimming, respiration and sensory systems during this period. The timing of finfold differentiation into unpaired fins (11-14 dph) is similar to that of tail growth pattern. Differentiation into unpaired along with growth of the tail and negative allometry of caudal peduncle in day 7 dph can be related to improve of fish swimming ability.