Mortalities and Exploitation Rate of Mediterranean Horse Mackerel, Trachurus mediterraneus (Steindachner, 1868) in the Central Black Sea

This study provides some actual information about length, weight, age, and mortality rates of Mediterranean horse mackerel (Trachurus mediterraneus) population in the central Black Sea in order to detect whether fishing pressure or not. A total of 1467 specimens were monthly collected from commercial purse-seiners, which especially landed to Sinop fishing port between September 2016 and March 2017. A total of 109 otoliths were used for age reading. Total length and weight of T. mediterraneus specimens were ranged from 7.1 cm to 20.3 cm (average: 14.02 ±0.04 cm) and 3.2 g to 67.7 g (average: 23.8 ±0.19 g). The samples were grouped densely between 12 and 15 cm and about 84% of samples in this study were within the legal size. Length-weight relationship was calculated as W = 0.0067 × TL3.0848 (r2 = 0.94). Age groups of horse mackerel in the central Black Sea were between I and III. Mean lengths according to age groups were 9.9 ±0.36 cm, 14.1 ±0.11 cm and 16.7 ±0.13 cm, respectively. Also, von Bertalanffy Growth Parameters were L∞ = 19.14 ±0.46 cm, K = 0.65 ±0.03, t0 = -0.08 ±0.007 year. Mortalities (M, F and Z) and exploitation rate (E) of T. mediterraneus from the Central Black Sea were 0.84 year-1, 0.87 year-1, 1.712 year-1 and 0.51 year-1, respectively. The rates of exploitation and minimum landing size indicate that there is no overfishing on T. mediterraneus population in the area for the time being.