Implementing the use of reef-ball artificial structures for oyster enhancement and finfish habitat restoration in Narragansett Bay, RI
The oyster (Crassostrea virginica) has historically supported an extensive fishery in Narragansett Bay, accounting for the largest commercial fishery in Rhode Island during the early 1900s. Since peak levels, however, harvests have declined precipitously and have yet to rebound in nearly a century. For example, in 1999, the estimated standing crop biomass of oysters in the Bay was 8.4 metric tons soft tissue dry weight. This biomass represents a thousand-fold decrease in oyster production over the course of the 20th century. The collapse of oysters in the Bay has been attributed to several anthropogenic and natural perturbations. Nevertheless, the economic and ecological benefits provided by a sustainable oyster population in the Bay have lead to substantial resources being allocated toward restoring the fishery in the state.
____Concurrent with the loss of oysters in Narragansett Bay has been a decline in finfish. Decreased abundances are especially prevalent for fish whose life history patterns are integrated with that of the oyster, such as the tautog (Tautoga onitis). The tautog is a valuable resource in the Northwest Atlantic, ranking seventh in recreational landings with an average annual harvest of 5.4 million pounds. This species inhabits reef-like structures during all post-larval stages, with biogenic reefs providing shelter and access to food. The dependence of tautog on specific habitat-types (e.g. oyster beds) makes any degradation or loss of these habitats a serious threat to the tautog resource. Recent stock assessments by the Atlantic State Marine Fisheries Commission (ASMFC) indicate that tautog numbers have declined fourfold over the last two decades. The loss of oyster beds in regions such as Narragansett Bay may account for the decline in tautog populations. The establishment of new "reef" habitat by artificial reef programs may be used to mitigate habitat degradation, and thus, restore finfish numbers to historical levels.
____In Narragansett Bay, economic and ecologic incentives have stimulated the growth of oyster enhancement projects since 1995. These shellfish restoration efforts have been narrowly focused, however, and have failed to maximize the potential benefits of oyster enhancement on the recreation of structured habitat for marine fauna. To this end, we are examining the dual benefits of an innovative artificial reef structure (i.e., Reef Ball™) for the enhancement of native oyster populations and the restoring of finfish habitat. Reef Ball™ technology is an advanced reef rehabilitation system that is widely used in tropical and subtropical waters for coral propagation, tropical finfish habitat, mangrove plantings, oyster reef creation, and erosion control. Our research is designed as a small scale effort to investigate the application of Reef Ball™ technology for oyster and finfish habitat enhancement in Narragansett Bay. Results of this study will provide insight for launching larger scale oyster restoration activities, as well as determining the use of Reef Ball™ in creating artificial sport fishing and diving reefs and as a management tool to establish finfish and shellfish spawning sanctuaries.
