<em>Abstract</em> .—The importance of molluscan-dominated systems (e.g., oysters reefs, mussel beds, vermetid gastropods) to the maintenance of commercially and ecologically important species has not been as broadly recognized as has been the importance of other structurally complex estuarine habitats such as sea grass beds and salt marshes. As a consequence, these systems have often been unappreciated and understudied. Important ecosystem services of molluscan-dominated systems include: (1) filtering capacity; (2) benthic– pelagic coupling; (3) creation of refugia from predation; (4) creation of feeding habitat for juvenile and adult mobile species as well as sessile stages of species that attach directly to molluscan shells; and (5) provision of nesting habitat. Destructive harvesting and overfishing can reduce habitat extent and impair habitat functioning. Only recently have ecosystem services been incorporated into the management of these systems. The role of oyster reefs as “essential fish habitat” falls into two principal categories: (1) reefs as habitat for oysters and (2) reefs as habitat for resident and transient species. Although the former role has received some attention as part of efforts to restore oyster resources, the latter role remains largely unexplored. The role of oyster reefs as critical habitat for other species is suggested by the diverse fauna associated with them; however, the factors that control the development of these reef-associated assemblages are generally unknown, and enumeration of specific habitat services using replicated field experiments is just beginning. Using data summarized from studies in Maryland, Virginia, North Carolina, South Carolina, and Texas, we classify finfish assemblages associated with reefs based upon the degree of their association and include an extensive finfish and decapod species list. We conclude, within the context of the current state of knowledge, that (1) the construction of reef bases using materials that provide adequate vertical relief and interstitial space and (2) the establishment of broodstock sanctuaries protected from harvesting pressure are important for restoring oyster populations. Utilization of reef habitats by numerous commercially, recreationally, and ecologically important species across a wide geographic range likely portends the reef habitats’ importance as essential fish habitat, but many functional relationships remain to be evaluated. Future oyster habitat research needs include (1) defining the morphological and spatial reef characteristics that support enhanced oyster growth and survival; (2) improving understanding of how harvest methods affect reef integrity and function; (3) determining the critical services provided by reef habitats in the life cycles of important species; and (4) further clarifying the trophic links between the resident fauna on oyster reefs and transient species.
Baseline data for evaluating development trajectory and provision of ecosystem services of created fringing oyster reefs in Vermilion Bay, Louisiana