Life History of Mediterranean Horse Mackerel Trachurus mediterraneus (Carangidae) from Crimea (Black Sea)

Abstract— The sex ratio, body length–age structure, growth rate, maturity dynamics, and mortality are studied in Mediterranean horse mackerel Trachurus mediterraneus from the shelf zone of Crimea. The sex ratio is close to 1 : 1, the maximum body length of the females and males is 22.5 and 20.8 cm, respectively, and the maximum age of the representatives of both sexes is 6 years. The sexual dimorphism in the growth rate is not revealed. The von Bertalanffy growth equation parameters for both sexes are as follows: asymptotic length and weight 19.0 cm and 57.4 g and growth coefficient 0.44 year–1. The females (50%) reach sexual maturity by 10.72 cm, and the males reach maturity by 10.53 cm at the age 1+. The spawning is observed from June to September. The maximum values of gonadosomatic indeces of the males (2.37%) and females (3.84%) are registered in June, and July, respectively. The coefficients of the total, natural, and fishing mortality are 1.41, 0.89, and 0.52 year–1. Within the entire range, the strong positive relationships between maximum body length, linear growth rate index and mean annual surface water temperature are registered. The difference in horse mackerel growth rate between various regions of the Black Sea is small. Nevertheless, the growth rate and maximum body length of the Black Sea individuals are smaller than these parameters in the Mediterranean Sea that is connected with the adaptation of the Black Sea population to climate seasonality.