The expansion of oyster aquaculture in Maryland’s Chesapeake Bay has renewed concerns about potential interactions with submerged aquatic vegetation (SAV), which provides critical habitat and ecosystem services. Current Maryland regulations prohibit aquaculture activities over SAV without written authorization, and exemptions to this rule (HB 841) are set to expire in 2024. In collaboration with the Maryland Department of Natural Resources and Choptank Oyster Co., we developed a before-after-control-impact monitoring study to evaluate the ecological interactions between surface oyster culture and SAV meadows within and adjacent to an active lease in the Choptank River.
From 2023–2025, we conducted coordinated surveys and environmental monitoring in both restricted and exempted lease areas, as well as in an adjacent natural SAV bed. SAV shoot density and species composition were quantified monthly, accompanied by high-frequency measurements of light intensity, temperature, and sediment characteristics. Light loggers were deployed beneath oyster gear, in non-gear areas, and within SAV meadows to assess shading and attenuation effects. Sediment cores were analyzed for grain size, organic matter, and the short-lived isotope ⁷Be to evaluate deposition processes and sediment origin.
Preliminary results indicate that SAV coverage remained low throughout 2023–2024, likely constrained by high freshwater inputs and associated nutrient loading that suppressed salinity in the Choptank River. Contrary to initial expectations, light availability beneath aquaculture gear was often higher than in adjacent off-farm areas, suggesting that oyster filtration may enhance water clarity. Sediment analyses revealed localized increases in organic content beneath adult oyster cages, consistent with biodeposition effects, though overall sedimentation rates remained low (0.2–0.3 cm·y⁻¹). No significant differences were observed in mud content or SAV recolonization between treatment areas over the study period.
This ongoing collaboration demonstrates a practical framework for evaluating aquaculture–SAV interactions and informing evidence-based management decisions. Results from this case study will contribute to guidance for balancing sustainable oyster production with SAV conservation in Maryland’s tidal waters and provide empirical data to support future policy and permitting decisions.