Comparison of cleithra, urohyal and hyomandibular bones for age estimation in Indian major carp Labeo rohita (Hamilton)

Labeo rohita specimens were collected from local fish market of Aligarh to observe the hard structures providing the most suitable age estimate. Total length (TL) of each fish was measured from tip of snout to the longest fin ray of the caudal fin. Each fish was weighed separately on a weighing balance, and the age of each fish was determined by using cleithra, hyomandibular bone and urohyal bone. Age estimates from different hard anatomical structures were used to calculate the correlation between the age readings from different pairs of ageing structure. Data generated on age estimates from the selected ageing structures were also subjected to student ttest .Standard deviation and standard error was also calculated for the age reading from a different pair of ageing structures. The statistical analysis was carried out by SPSS v.12. Comparison of different structures revealed cleithra to be the best ageing structure for estimating age. So, in case of fish with unreadable scales use of cleithra for age estimation of L. rohita