Body shape change in Common carp, Cyprinus carpio var. Sazan, during early development using geometric morphometric method

This research was conducted to study the body shape changes in common carp, Cyprinus carpio var. Sazan during early developmental stages using landmark-based geometric morphometric method. For this purpose, a total number of 210 larvae from hatching time till 55 days post hatching (dph) were sampled. For extracting body shape data, the right side of specimens was photographed and nine landmark-points were defined and digitized on 2D pictures using tpsDig2 software. After GPA, the landmark data were analyzed using Relative Warp analysis, regression of shape on total length and cluster analysis. The results showed that change of body shape in common carp during early development includes (1) increase in the head depth, and trunk length from hatching up to 8 dph, (2) increase in the body depth, and the head and tail lengths from 8-20 dph, and (3) increase in the head length and depth from 20-55 dph. The cluster analysis was revealed that larval stages can be divided into four phases, including eleuthero-embryonic, larva, younger juvenile and juvenile. Based on our finding, the body shape changes of this species during early development is due to adjusting of vital priority.