<p>The study presents one-year monitoring data on the meat yield index, morphometric parameters, and sex structure of the mussel <i>Mytilus galloprovincialis</i>. Mussels were collected from seven locations in the Black Sea and the Sea of Azov that differ in anthropogenic pressure and hydrochemical characteristics. Differences were observed between cultivated and wild mussels for the studied parameters. The meat yield index was slightly higher in cultivated mussels from the shellfish farm (21.8 ± 4.1%) than in wild populations (20.9 ± 6.1%). Statistical analysis revealed that both season and sampling location significantly influenced meat yield, with month-to-month variations differing among locations. Anthropogenic pressure did not have a decisive effect on mussel meat yield. Morphometric indices indicated that environmental conditions influenced shell shape variability in <i>M. galloprovincialis</i>. In wild populations, the shell height-to-length ratio (H/L) was 0.57 ± 0.05 and the width-to-length ratio (D/L) was 0.38 ± 0.10, whereas in cultivated mussels, these ratios were 0.54 ± 0.03 and 0.37 ± 0.03, respectively. The shells of cultivated mussels were more elongated and less convex, suggesting more favorable growth conditions in the mussel farm environment. Variations in these morphometric parameters can be used to assess mussel well-being and to distinguish between different populations of the same species. Across all studied water bodies, the sex ratio of <i>M. galloprovincialis</i> was skewed toward males. In cultivated mussels, the female-to-male ratio was 0.57 ± 0.35, whereas in natural populations it was 0.49 ± 0.31.</p>