Otolith morphometry for the determination of the theoretical growth curve of fish

During the period from November 2019 to August 2021, a total of 43 specimens of Leporinus friderici, 18 of Prochilodus lineatus, 17 of Hoplias intermedius and 8 of Cichla kelberi were caught in the Verde River basin (Mato Grosso do Sul, Brazil) using various types of fishing equipment. Data collection consisted of measuring fish lengths (LOa, mm) and area (Oa, mm2) of their respective sagitta otoliths. The modified Von Bertalanffy equation (1938) was used to determine the theoretical growth curve as a function of the otolith area. The results indicate that the length of the fish increases in relation to the increase in the otolith area, resulting in a strong logarithmic regression for all species studied. The values of the theoretical growth curve of the fish (observed and estimated) as a function of the areas of the otoliths showed adjustments of R2>75 for the measured and R2>90 for the estimated values. Therefore, the otolith area proved to be adequate for the estimation of growth for the species, which can also facilitate the evaluation of fish length, band is a useful tool for the evaluation of fish stocks.