Population biology and status of exploitation of introduced garfish Belone belone euxini (Gunther, 1866) in the Black Sea

Abstract

The garfish Belone belone euxini (Gunther, 1866) is a commercially important pelagic fish species in Sinop artisanal fishery, which is showing a decreasing trend in catch results. As a basis for fisheries management a sampling program was carried out between October 2000 and September 2001 along the Turkish coast of the Black Sea, to study the population structure, growth, and reproduction cycle of garfish in the area, and to achieve a rough estimate of exploitation. The length-weight relationship and von Bertalanffy growth parameters were estimated as W = 0.00076 L-3.137, L-infinity = 74.64 cm, K = 0.13 year(-1), t(o) = -3.67, respectively. First sexual maturity was estimated at age 2 and at a total length of 38.8 cm for females. The spawning period was from May to September. The total fecundity-length relationship was estimated as F = 0.0041 L-4.1086 (r(2) = 0.92). Mortality rates were Z = 1.24 year(-1), M = 0.23 year(-1)and F = 1.01 year(-1) for total, natural, and fishing mortality, respectively. The exploitation ratio E = 0.81 indicates that the population is heavily exploited.