Fisheries and population dynamics of garfish (Belone euxini Günther, 1866) in the Eastern Black Sea (Rize coast)

Fisheries and Population Dynamics of Garfish (Belone euxini Günther, 1866) in the Eastern Black Sea (Rize Coast) To describe the age, growth, mortality, distribution, spawning time, fecundity and size at sexual maturity of the garfish, Belone euxini and differences in these parameters from other populations, monthly samplings were conducted between December 2011 and July 2013 off Rize coast in the southeast Black Sea. The mean total length (TL) of female was significantly greater than the mean total length of male (P < 0.05). Sex ratio of female: male with size was towards male up to 38 cm length class and, it was skewed towards female for greater than 38 cm size class (P < 0.05). The exponential (female: L∞ = 88.3 cm TL, K = 0.108 year-1, male: L∞ = 71.9 cm TL, K = 0.151 year-1) and von Bertalanffy (female: L∞ = 81.6 cm TL, K = 0.125 year-1, t0 = -2.25 year, male: L∞ = 81.6 cm TL, K = 0.125 year-1, t0 = -2.13 year) models considered as the most suitable growth models. Total instantaneous mortality rate, Z, was estimated as 1.04 year-1 for female and 1.24 year-1 for male. Absolute fecundity ranged between 4015 and 32453 number/individual (mean: 14365±1049 number/individual) and mature eggs that was left for each spawning portion (batch fecundity) ranged between 560 and 9713 number/individual (mean: 2338±243 number/individual). Mean diameter of immature eggs in ovary was significantly lower than mature eggs (t-test: P = 1.54E-230). Monthly proportion of ovaries and testes maturity stages and monthly GSI values showed that the spawning period of garfish was between May and September. The size at 50% sexual maturity (TL50) was estimated as 34.4 cm TL for female and 33.3 cm TL for male. Key Words: Belone euxini, growth, mortality, reproduction, fisheries management