| In order to determine the relationship among the otolith radius. Body length and age of fishes, the otolith of 513 large croakers Pseudosciaena crocea caught from the Dongtou and Lusi fishing ground in the East China Sea in March and April, 1960 were cut open for study and their ages were determined. Analysis of the growth patterns of otoliths and body lengths showed that otolith size was positively related to age of the fish, and that the otolith radii of the fishes of the same age were positively related to the fish lengths.
According to the stochastic process theory, otolith growth is divided into a first stage of otolith growth in pace with age and second stage of otolith growth in pace with body growth. This hypothesis relates otolith radius to the age and body length of large croacker as expressed in the formula, r = Ale-Kt+B(1 - e-Kt)+C, and according to a similar hypothesis, the relation of the body length of large croacker to that of the age and otolith radius can be deduced as l = Are-Kt+B(1 - e-Kt) +C, where, l is body length, r is otolith radius, t is age, and A. B, C and K are empirical parameters. By means of the iteration method, we simulated the relationship of the body length, otolith radius and age of the large croacker. The results showed that the equation expressed the relationship very precisely. |
