The role of ontogenetic development in fish scale shape changes

Abstract

Fish scale investigation has been used in many ways. Recently several species’ scale shape was used to differentiate species, populations or stocks. Effects of allometric growth on scale shape proved to be a common phenomenon in case of numerous species, however there is no information regarding the impact of temporal (ontogenetic timescale) changes. In this study the effect of intrapopulation age distribution on the scale shape was tested. Seven age groups of a gibel carp (Carassius gibelio) population were identified and analyzed using landmark-based geometric morphometric methods. The results indicated a clear trend of ontogenetic-driven shape change of gibel carp scales: the adult fish specific scale shape occurs at the age of 3+, along with sexual maturation, the alterations among the older age classes show no significant differences. These results suggest that the asymmetric age distribution of fish populations should be taken into consideration during scale morphometric analyses.