Age, growth, reproduction and diet of the whiting, Merlangiu merlangus euxinus (Nordmann, 1840), in the southeastern Black Sea

Abstract

Age structure, growth, reproduction and diet of the whiting, Merlangius merlangus euxinus, were studied on a total of 598 whiting between December 2004 and November 2005 in the southeastern Black Sea. The total length of females was statistically higher than the one of males (t test,/p < 0.001). The age range estimated was up to 6 years for females and 5 years for males. To obtain reliable estimates of growth parameters, three growth models (von Bertalanffy, Gompertz and Richards) were applied for both sexes. Gompertz {AIC = 1901.46) and von Bertalanffy (AIC = 1853.71) were the most suitable models to fit age-length data for females and von Bertalanffy considered as the most suitable growth model due to goodness of fit for males. Spawning occurred throughout the year with three peaks: firstly end of winter, secondly middle of spring and thirdly end of autumn. Whiting mostly feed on three fish species: anchovy (IRI% = 35.01), whiting (IRI% = 34.07) and sprat (IRI% = 22.81). ANOSIM showed that significant differences in the prey species composition existed between the seasons (R = 0.1149,/p < 0.001) and SIMPER analysis also revealed that the most contributing species to the differences between seasons was anchovy.