THE RELATIONSHIP BETWEEN OTOLITH-WEIGHT AND AGE WITH REFERENCE TO ITS USE IN AGE DETERMINATION FOR CARASSIUS AURATUS

The relationship between otolith weight and age in Carassius auratus and the use of otolith weight for validating annulus counts on otolith were being investigated.It was exhibited that otolith weight had little overlaps among age classes,and for individuals with similar body length,the older (slower growing)had bigger otolith weight than the younger(faster growing).There were significant differences in otolith weight among different age classes(ANCOVA,body length as covariate)and the otolith weight had significantly positive linear relationship with age (P0.05).The age readings could be verified by plotting the otolith weight vs body length for age classes,and the individuals with similar body length but different ages could be separated by otolith weight frequency analysis.It was demonstrated that the "estimated" ages from regression between otolith weight and ages had no significant differences with the "true" ages from annulus counts on otolith.It was suggested that the otolith weight was a useful technique for validating the accuracy of age determination from annuli counting, especially for the individuals with similar size.Meanwhile, the potential of otolith weight for direct estimation of ages of C.auratus were explored by the authors in this paper.