Akademik Veri Yönetim Sistemi
THALASSAS, cilt.41, sa.4, 2025 (SCI-Expanded)
Mass-marking of otoliths provides fisheries managers with a scalable and minimally invasive method for tracking juveniles released during stock enhancement and restocking programmes. The turbot (Scophthalmus maximus) is a high-value flatfish whose wild populations have experienced severe declines due to overfishing and habitat degradation. To support evidence-based management and optimise restocking success, we evaluated the safety and marking reliability of two fluorescent markers - alizarin complexone (ALC; 50 mg/L) and oxytetracycline (OTC; 50-400 mg/L) - applied via 24-hour immersion in aerated fibreglass tanks. A total of 1,950 juveniles at three developmental stages (30, 50, and 70 days post-hatch) were exposed, with a subset receiving a second immersion 20 days after the initial treatment to assess double-marking feasibility. Survival exceeded 98% across all treatments, with no significant differences in mortality between marker types, concentrations, or age classes. Fluorescence microscopy revealed clear, persistent red (ALC) and green (OTC) bands in sagittal otoliths, enabling reliable identification of single and double-marked cohorts. These findings demonstrate that both ALC and OTC are effective, low-stress marking agents suitable for large-scale turbot stocking programmes, offering fisheries managers a dependable tool to monitor release cohorts, evaluate post-release performance, and inform adaptive management of wild turbot populations.