Site-based comparison of environmental conditions and biochemical composition of mussels (Mytilus galloprovincialis) across different aquaculture areas in Aegean Sea, Türkiye

Abstract This study comprehensively evaluates the environmental conditions, meat yield, condition index, biochemical composition and fatty acid profiles of mussels ( Mytilus galloprovincialis ) from different aquaculture sites (tuna farm, fish farm – sea bream and sea bass, mussel farm) and a natural reference site in Türkiye. Water temperature, salinity, and chlorophyll a levels were monitored monthly. The average water temperature ranged from 16.3 °C in winter (December) to 26.6 °C in summer (July), with mussel farm and natural reference site exhibiting slightly higher temperatures during warmer months. Salinity and chlorophyll a levels were higher at mussel farm and natural reference site (39–39.3 PSU and up to 10.45 µg L −1 , respectively), indicating favorable conditions for mussel growth. In contrast, tuna farm and fish farm showed lower salinity (34–38.9 PSU) and chlorophyll a levels (0.06–2.29 µg L −1 ), suggesting suboptimal nutrient availability. Meat yield and condition index values varied significantly among the sites, with the highest meat yield and condition index observed at mussel farm (40.27% and 23.96%; respectively). Biochemical analysis indicated that mussels from all sites were rich in protein (50–65%) and ash (10.9–16.9%), with fish farm showing the highest protein content (65%). Fatty acid analysis revealed high levels of omega-3 fatty acids, particularly docosahexaenoic acid (DHA, 21.4%) and eicosapentaenoic acid (EPA, 13.5%), across all sites. The findings highlight the significant influence of trophic conditions, particularly chlorophyll-a availability, on mussel growth and nutritional quality. Mussel farm and natural reference site exhibited comparatively more favorable local conditions during the study period, underscoring the strong influence of site-specific trophic variability on mussel performance. This study provides valuable insights for optimizing mussel farming practices and promoting sustainable aquaculture in Türkiye. The results provide preliminary insight into whether organic inputs from finfish and tuna farming may partially compensate for limited phytoplankton availability in offshore production areas.