Investigation on the growth and feeding characteristics of false scad (Caranx rhonchus Geoffroy Saint-hilaire, 1817) in Izmir Bay (Aegean sea)

The aim of this study is to investigate the growth and feeding characteristics of 392 false scad (Caranx rhonchus) obtained from commercial fishermen caught in İzmir Bay between September 2017 and July 2018. To generate the growth parameters of the obtained samples, total length and body weight has been measured; otoliths were taken for age estimation and stomach samples were taken for the examination of stomach contents. A total of the 392 individuals has been determined as 184 were female, 149 were male and 59 individuals were undetermined gender. The total length values of all individuals were between 12.8-36.0 cm and their weights were measured as 23.51- 455.44 g. Length-weight relationship equations has been calculated for female individuals W=0.0141*L2.900 (R²=0.965), for males W=0.0168*L2.842 (R²=0.967), and for all individuals W=0.0132*L2.926 (R²=0.968). As a result of age estimation, it was found that individuals were in I-V age range. Von Bertalanffy growth parameters for female, male and all individuals respectively; L∞=39.54 cm, K=0.2156 years-1, to=-0.963 years, L∞=40.86 cm, K=0.2181 years-1, to=-1.0584 years, L∞=41.12 cm, K=0.2061 years-1, to=-1.0548 years; index of growth performance (Ф) values were found as 2.555, 2.532 and 2.542. As a result of the stomach contents of 125 individuals, it was found that this species was predominantly fed with Crustacea (%N=52.30; %F=36.0) in İzmir Bay.