A research on the determination of stockstructure and population parameters of horse mackerel (Trachurus mediterraneus, Steindachner, 1868) in the Eastern Black Sea

In the study, some basic population parameters of horse mackerel (Trachurus mediterraneus, Steindachner, 1868) in Eastern Black Sea were investigated.During the research period a total of 690 specimens were sampled from fishermen in Trabzon by random sampling. Total lengths of the mediterranean horse mackerel specimen ranged from 6,2 to 20,4 cm. Mean total length values were estimated as 11,83±2,16 cm for whole specimens, 11,45±2,14 cm for males and 12,28±2,12 cm for females.Length-weight relationships were determined for whole specimens as; W= 0,0067×L3.165, for males; W= 0,0065×L3.148, for females; W= 0,0068×L3.183 . Age-length relationship was estimated as Lt= 29,467(1-e -0.115(t+1.855)) and age-weight relationship was also determined as Wt= 300,92(1-e -0.115(t+1.855))3.165.During the study period, instantaneous rate of mortality for horse mackerel; (Z) 2,25 year-1, rate of naturel mortality (M) 0,32 year-1, rate of fishing mortality (F) 1,93 year-1 and expolitation rate (E) 0,85 year-1were estimated respectively. In the mean time, F0,1 was also estimated as 2,55 meaning that current fishing effort in use in The Black sea (purse seine) has resulted an under exploitation of mackerel stock unlikely the anchovy which faced an overfishing threat in the Black Sea.