Studies on the growth checks on scales and opercles and their validity in age determination ofChanna punctata (Bloch, 1793) (Pisces, Teleostei, Channidae) from Guntur, Andhra Pradesh

Abstract

Specimens with growth checks in process of formation on both scales and opercles occur throughout the year. When a growth check is formed on the scale of a particular specimen, it does not necessarily mean that it is being formed simultaneously on the opercie of the same individual, orvice versa. A maximum of 8 and 6 growth checks in males and females respectively are observed on both scales and opercles. There is a positive correlation between total length and number of growth checks on both hard parts. Values of average length and observed number of growth checks show that there is no gradual decrease in the rate of growth. Scales and opercles show differences in the number of growth checks in many specimens. The first growth check is not formed during the same period of the year in ail individuals. There is no gradual decrease in the distance between successive growth checks. Considerable numbers of adult females in all stages of maturity show growth checks in the process of formation revealing that the spawning stress or reproductive strain is not the only factor leading to growth check formation.