Life cycle and otolith morphological parameters of black scorpionfish, Scorpaena porcus (Scorpaenidae) in the Crimean waters of the Black Sea

Sex, size and age structure, growth, mortality, and some of the morphological parameters of the otoliths of the black scorpionfish, Scorpaena porcus collected in the south-western Black Sea waters of the Crimea were analyzed. A total of 500 S. porcus specimens were examined. The total sex ratio differed (1.00:0.67) with the predominance of females. The maximum total length and age of females were estimated to be 26.9 cm and 12 years old, respectively; for males, they were 21.3 cm and 11 years. The growth rate was determined to be sex-specific. The values of the parameters of the Bertalanffy equation were calculated. For females, the asymptotic total length was estimated to be 28.9, weight – 519.7 g, parameter k = 0.10 year-1, to = -2.90; for males, the asymptotic total length was estimated to be 23.2 cm, weight, 226 g, parameter k = 0.16 year^-1, t_o = -2.13. The total, natural, and fishing mortality coefficients for females amount to 0.67, 0.45, and 0.26 year^-1, respectively; for males, they are 0.46, 0.30, and 0.13 year^-1. The exploitation ratio for females is 0.38, and for males, it is 0.28, corresponding to the low fishing pressure. The relationship between the fish length and the otolith length is isometric, but the relationship between the fish weight and the otolith weight is positively allometric. The Black Sea black scorpionfish differs from the Mediterranean population by their bigger maximum sizes, low growth rate, longer lifespan, and more evident sexual dimorphism.