Population Genetic Analysis of Garfish Belone belone from the Bulgarian and Turkish Coasts of the Black Sea

Belone belone is an epipelagic migratory species widely distributed in the northeast Atlantic, Mediterranean and Black Sea. It is a fish species of high economic importance especially for the Mediterranean and Black Sea. An understanding of the genetic structure and diversity of marine fish populations can inform the development of fishing restrictions aimed at preventing overfishing. In this study, we were to investigate the population structure of Belone belone from the Bulgarian and Turkish coasts of the Black Sea with simultaneous use of the mtDNA COI gene and morphology. The results show that genetic diversity was much lower in the Nesebar (0.0004) population than in the Akçakoca population (0.0154). The average genetic diversity value between populations was 0.0107. A total of five haplotypes were found out of 40 sequences, and haplotype I was a common haplotype between populations. The average haplotype diversity was found to be 0.4513. Haplotype diversity within the population observed was 0.5947 in the Akçakoca and 0.1947 in the Nesebar population. In morphological analyses, 16 morphometric and 6 meristic characters were used. According to Canonical Discriminant Function Analysis, the first discriminant function expressed 100% of the total variation. According to the PCA, the first principal component accounted for 23.4% of the total variation and the second principal component accounted for 16.03% of the total variation. The present study revealed the genetic and morphologic differentiation coupled with low genetic diversity at the margins of the geographical separation of B. belone in Bulgaria and Turkish marine waters. Therefore, The Bulgarian and Turkish sides should consider urgent mutual management measures for the conservation of B. belone populations in Bulgarian and Turkish marine waters.