We plan a small-scale Olympia oyster, Ostrea lurida, restoration effort in an area of Newport Bay, CA that previously supported oyster beds by augmenting the amount of hard substrate available for oyster spat using undergraduate and graduate students, scientists, private citizens and local community non-profit groups.

While restoration projects are well underway in Washington, Oregon and in northern California, the Olympia oyster has been relatively understudied in southern California until recently. While no quantitative data on oyster density in Newport Bay is available prior to Polson and Zacherl (2009), historic documents do indicate the presence of oyster beds in several southern California estuaries, including Mugu Lagoon, Alamitos Lagoon and Newport Bay that supported artisanal -scale harvesting and very small-scale fishery operations.

Recent extensive field surveys of the entire bay reveal that while oysters currently range from present and rare to somewhat common, there is currently no natural intertidal bed of oysters anywhere in Newport Bay. At highest density (at the site proposed for this restoration effort, hereafter called Castaways mudflat), they measured 54 5.8 oysters/m2 on a mudflat that was 44% mud and ~ 56% hard substrate in the form of unconsolidated gravel, shell, small, medium and large boulders. Four years worth of larval spatfall data in Newport Bay indicate that the native oyster is actively reproducing and recruiting to local populations during June - September, with maximal settlement typically in August and in especially high densities (as high as 3,000 to 8,000/m2) in the upper bay just adjacent to the proposed restoration site. Augmentation of suitable habitat, then, seems the most logical first restoration step since spat appear to be in ready local supply but suitable settlement habitat is limited.

Thus, the specific objective of this project is to supplement suitable settlement habitat for oyster spat in a pilot study where 2 m X 2 m replicate (n=5) plots will be constructed to test the effects of 4 different bed morphologies (unconsolidated versus bagged shell at two thicknesses each) on out-planted oyster shell retention, oyster recruitment, growth, and survival, and on community biodiversity. Control plots will test the hypothesis that habitat availability is constraining population density (i.e. that habitat augmentation will result in increases in oyster abundance and survival). A total of 25 plots will be randomly arrayed in a 100 X 2 sq meter swath of mudflat, with each experimental plot separated from neighboring plots by 2 meters. Long-term plans include expansion of restoration activities to include at least two additional locations within Upper Newport Bay.