Age, growth and mortality of black goby Gobius Niger Linneaus, 1758 (Family: Gobiidae) from the south-eastern Black Sea

Abstract

This study intends to determine the most reliable structure for age estimation and to assign the population parameters from two fishing grounds under different fishing pressures. The age, growth and mortality of the black goby from the Kızılırmak-Yeşilırmak shelf area (KYSA) and Melet River shelf area (MSA) were investigated through 2751 specimens. The reliability of the age structures were controlled by the estimated aging criteria, such as agreement, the average percentage error and the coefficient of variation. The von Bertalanffy growth model was used to reveal the growth parameters, and the growth curves derived from two regions were compared by Likelihood ratio test. The total mortality rate was estimated by the method of Linearised Catch Curve and the natural mortality rate by Pauly’s empirical formula. Otolith is found to be the most reliable aging structure for the black goby. The equations of the von Bertalanffy growth model were estimated as Lt= 13.26 [1– e–0.31 (t– (–1.43)] and φ= 1.73 for KYSA, as Lt= 13.96 [1– e–0.29 (t – (–1.42)] and φ= 1.75 for MSA. The growth model derived from the samplings of KYSA and MSA were detected as significantly different according to likelihood ratio test.