Ontogenetic changes in flippers morphometrics in bottlenose dolphins (Tursiops truncatus)

The aim of the present study was to investigate and compare the morphometric characteristics of the flippers in male and female bottlenose dolphins (rursiops truncatus) of various ages. We investigated the right flippers of 64 bottlenose dolphinc specimens - 36 males and 28 females, in an age span of from 6 months to 28 years. Two numeric indices were suggested in order to establish the numerical relationship between the external measures of the flipper and the total body length of each animal. The index of the flipper measurements (IxF) directly showed the differences in flipper sizes in the investigated dolphins, whereas the index of the flipper measurements and the total body length (IxBL) displayed the differences in the flipper size in relation to the body length of the studied dolphins. By comparing these indices in dolphins of different ages, noticeable variations in flipper dimensions during total body growth were observed. In bottlenose dolphins, both flipper indices were highly correlated with the animal's body length. The mean value of the index of the flipper measurements and the total body length (IxBL) was somewhat higher in female bottlenose dolphins. Both the flipper indices were highly correlated with the animal's age. and our results suggest that the flipper grows until the tenth year of age, after which it does not change substantially until the 25th year of age. After that age the flipper size starts to decrease.