Age determination and growth of the freshwater catfish, Tandanus tandanus Mitchell, in the Gwydir River, Australia

Abstract

Dorsal spines of T. tandanus from the Gwydir River were used for age determination. Annuli were formed in winter (June-July). The validity of age determination and accuracy of lengths back- calculated from spine radius measurements were supported by tagging data and examination of known age fish. No differences in growth rates were detected between males and females. The variation in growth from season to season was not great. The von Bertalanffy and Gompertz growth equations were used to describe growth in length and weight respectively. The maximum size of catfish in the Gwydir River predicted by these equations was 596 mm and 2605 g.