Y A Research on Bioecological Properties of Anchovy (Engraulis encrasicolus L. 1758) and Mackerel (Trachurus mediterraneus) Fishes in the Eastern Black Sea Ecosystem

SUMMAR Feeding ecology, stock structure and onset of sexual maturity of two pelagic species, Anchovy Engraulis encrasicolus, L. 1758 and Horse mackerel, Trachurus mediterraneus, inhabiting in the Black Sea and both are economically important species, were investigated during the course of study in the Eastern Black Sea Region. The results include; stock structure of both species, growth, mortality, condition factors, sexual maturity, recruitment, and VPA analysis, feeding ecology, prey diversity and prey preference were also included for those two pelagic species. The data obtained during the sampling period of 1996-1997 showed that the length of Horse mackerel ranged from 6.3 cm to 17.8 cm. for the age classes concerned the average length were estimated as 8.61 cm of "0+", 10.49 cm of "1+", 13.56 of "2+" and 15.59 cm of "3+". The length of anchovy ranged from 6.2 cm to 13.5 cm. 7.93 cm. 9.99 cm and 12.13 cm were estimated for the age classes of 0+, 1+, and 2+ respectively. The study has revealed that length weight relationship for both species were found to be as following; W=0.0108*L:!98 Horse mackerel W=0.00569*L3"7 anchovy It was also found that female Horse mackerels each their sexual maturity when they are about 12 cm (L50: 12.12 ± 0.234). This is about 13 cm (L50: 13.32 ± 1.06) for males. For the anchovies. L50 for male and female were 8.9 cm ± 1.66 and 9.3 ± 0.017 cm respectively. Both anchovy and Horse mackerel feed mainly on Calanoid Copepods (% 95). Therefore it is though that there might be a strong competition between those two pelagic species. Key Words: Anchovy, Mackerel, Feeding Ecology, Sexual Maturity, Stock, The Eastern Black Sea IX