The Texas Parks and Wildlife Department (TPWD) typically conducts oyster reef restorations by placing “cultch” (shell or rock material) on degraded reef, thereby providing increased surface area for juvenile oyster settlement. However, in recent years, the cost of cultch material and placement has been increasing exponentially. In response, TPWD constructed several “experimental” sites to identify the most economically and ecologically effective approaches to oyster restoration. Restoration designs tested include using different (1) placement configurations—i.e. ‘mounds’ with significant vertical relief vs continuous, uniform ‘flats’ layers, (2) depths of cultch material in both ‘mounds’ and ‘flats’ configurations, and (3) spatial intervals using the ‘mounds’ configuration. The experimental treatments were monitored bi-annually using hydraulic oyster patent tongs to monitor oyster recruitment, growth, and survival.

All designs tested resulted in increased oyster abundances, comparable or exceeding those of nearby natural reefs. Costs for each restoration strategy varied as a function of total volume of cultch required to cover the same spatial footprint. Here, we present the preliminary results of cost-benefit analyses to investigate the average output (in terms of production of juvenile, subadult, and adult oysters) per dollar spent for each respective approach. Our assessments suggest that layers placed using a smaller volume of cultch per unit area may result in more cost-effective production of oysters over the short-term, although they may not produce higher total abundances. Additional monitoring and analyses are needed to assess long-term restoration success as it relates to resiliency and ‘spill-over’ impacts to adjacent, unrestored reefs.