A study on the growth of horse mackerel (Trachurus mediterraneus Aleev, 1956) from Bulgarian waters of the Black Sea using length frequency analysis
Institute of Oceanology, Bulgarian Academy of Sciences, Department of Marine Ecology and Biology, 40 First of May Street, Po. B. 152, 9000 Varna, BULGARIA
Length frequency data of horse mackerel Trachurus mediterraneus ponticus were collected from commercial net catch from Bulgarian Black Sea waters. Sampling covered the fishing season from May to December in 2012. FISAT II software program was used to analyze its length frequency distribution. The corresponding values of asymptotic length L∞ using ELEFAN I ranged from 18.11 and 19.26 cm, K values were 0.51 year-1 and 0.44 year-1 , for males and females, respectively. L∞ estimated by Bhattacharya and Ford-Walford method ranged from 18.90 and 19.11 cm for males and females, respectively. Meanwhile,L∞ by Wetherall and Bertalanffy method shows 18.24 and 18.78 cm for males and females, respectively. The instantaneous rate of total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated and accordingly the exploitation ratio was determined. The Z estimated by length cohort analysis ranged from 1.42 for females and 1.62 for males. The Beverton relative yield per recruit model analysis showed that EMSY, the maximum (Y’/R), was obtained at nearly the same value for females =(0.37) and males (0.38).
Keywords: Population parameters, mortality, exploitation rate, horse mackerel, Black Sea