Population dynamics of the garfish, Belone euxini (Belonidae: Belone) from the south-east Black Sea

Abstract

To describe the age, growth, mortality and distribution of the garfish, Belone euxini and differences in these parameters from other populations, monthly samplings were conducted between December 2011 and July 2013 in the south-east Black Sea. Garfish catch decreased to its lowest levels in spring months, especially after May, and it was completely finished by the summer months. the mean total length (TL) of the female was significantly greater than the mean TL of the male (P < 0.05). the sex-ratio of female: male with size was skewed towards males up to 38 cm length-class, and skewed towards females above the 38 cm class (P < 0.05). the growth pattern of garfish was described by goodness of fit of the data and biological interpretation of growth parameters. the exponential (females: L-infinity = 88.3 cm TL, K = 0.108 yr(-1), males: L-infinity = 71.9 cm TL, K = 0.151 yr(-1)) and von Bertalanffy (females: L-infinity = 81.6 cm TL, K = 0.125 yr(-1), t(0) = 22.25 year, males: L-infinity = 81.6 cm TL, K = 0.125 yr(-1), t(0) = 22.13 year) models were considered the most suitable growth models. Total instantaneous mortality rate, Z, was estimated as 1.04 yr(-1) for females and 1.24 yr(-1) for males. Instantaneous natural mortality ratio, M, was estimated higher for males than for females. the exploitation rate of both sexes was also higher than the optimum exploitation (E = 0.5) criterion, which is indicative of overfishing of the garfish population.