La Peyre, M., Furlong, J., Brown, L.A., Piazza, B.P., Brown, K. 2014. Oyster reef restoration in the northern Gulf of Mexico: extent, methods and outcomes. Ocean and Coastal Management 89:20-28.
Abstract
Shellfish reef restoration to support ecological services has become more common in recent decades, driven by increasing awareness of the functional decline of shellfish systems. Maximizing restoration benefits and increasing efficiency of shellfish restoration activities would greatly benefit from understanding and measurement of system responses to management activities. This project (1) compiles a database of nGoM inshore artificial oyster reefs created for restoration purposes including critical planning, location and construction data, and (2) quantitatively assesses a subset of reefs to determine project outcomes. From Nueces River, TX to Apalachicola, FL, we documented 260 artificial inshore reefs created for ecological restoration. Information on reef material, reef design and monitoring was located for 93, 43 and 13 % of the reefs identified. Of reefs with available information, 52% were created using rock substrate, and 20% using shell. Project costs and monitoring information were available for very few reefs (< 15% of projects). To quantify restoration success, we used diver surveys to quantitatively sample oyster density and substrate volume of 11 created reefs across the coast (7 with rock; 4 with shell), paired with 7 historic reefs. Total volume of structure (L m-2) and adult oyster densities (ind m-2) were higher on rock reefs than on historic or shell reefs, but spat density was higher on historic reefs, and lowest on shell reefs. Site location, combined with potential material and reef design effects which were often poorly documented, and difficult to discern may contribute to reef outcomes. These data highlight the need to track restoration projects, including information on project design to better inform future activities; explicitly identifying aspects of design, location, and their interaction that influences project outcomes is critical to improving this rate of success. Adaptive management protocols seek specifically to maximize short and long-term restoration success, but are critically dependent on measuring system responses to management activities.