Intertidal oyster reefs can persist and function in a temperate North American Atlantic estuary

Abstract

Intertidal oyster reefs in lower Delaware Bay are ephemeral and it is generally assumed that oyster mortality due to predation, disease and winter ice scouring inhibits their persistence. In June 2006, shell-bag oyster reefs of varying height were constructed on the intertidal sand flats in lower Delaware Bay, USA, to determine the potential for oyster reef restoration in this temperate estuary. Oyster settlement, mortality and recruitment were compared among reefs, as was habitat value for motile fauna. Oysters recruited shortly after reefs were constructed. Motile macrofauna immediately began using the reefs, increasing species richness and abundance relative to the adjacent sand flat. Little post-settlement mortality was observed in oysters by October 2006 and most survived exposure to snow and ice during winter. Shifting sediments nearly buried the shortest reef by April 2007, a process that may be more important in limiting the development of oyster reefs in this system than predation, disease or ice shear. Results indicate that there is good potential for the development of intertidal oyster reefs in this region. © Inter-Research 2008.