The goal of this study was to identify the best calcified structure for determination of the age of the piracatinga (Calophysus macropterus). A total of 440 specimens from commercial samples and experimental fishing in the Solimões River. Were used for analysis: Opercula, otoliths, and vertebrae were analyzed from a sub sample (n=130). Two clarification techniques were used for visualization of growth rings in the otoliths and four coloration techniques for vertebrae. The otoliths were not translucent and it was very difficult to see the growth rings. The vertebrae were the best calcified structure because the radius of the vertebrae and the length of fish had clear significant linear relationship (r= 0.91; P<0.05) and a clear visualization of the growth rings. Among the techniques used for examining vertebrae of the teleostean fishes, the chemical decalcification, hyper-oxidation technique, was the best to observe the growth rings in the vertebrae. The seasonal rings were validated using relative marginal incremental analysis. Two annual rings are formed in the vertebrae of Calophysus macropterus, being the first during low water (August) and the second during high water season (January). On the vertebrae, a maximum of seven rings were observed.
Otoliths; opercula; vertebrae; Calophysus macropterus; Solimões river
