Determination of two-phase growth in demersal fish species from the southern Black Sea coast

The von Bertalanffy growth model (VBGM) is often preferred in the estimation of growth parameters and curves in bony fishes but is rarely evaluated for its accuracy. The aim of this study is to prove that the growth period of some demersal fish species is biphasic. Two growth models (two-phase growth model (TPGM) and VBGM) were used to estimate the growth parameters of the mentioned species and the results were compared by Akaike's Information Criterion (AIC). In 11 cases out of 15 which were tested for different sexes and combined sets, TPGM was determined to reveal more reliable estimations and provides better goodness of fit according to Akaike's Information Criterion (AIC), Δ i, and w criteria. It is also found that VBGM tended to yield higher L ∞ values and therefore should not be considered as the unique model. It is concluded that the two-phase growth model was the best model for overall cases in this study and it is recommended that comparisons should be performed among different models before the construction of a growth curve for any fish species.