Dataset: Oyster density

To quantify oyster density and demographic rates on natural intertidal oyster reefs and hardened shorelines, the reef sites from the ground-truthing survey that met a minimum density criterion (10 live oysters per m2) were revisited and continuously sampled. The present study’s sampling protocol was adapted from Drexler et al. (2014) and ensured that the reported measurements represented all living oysters existing on all available substrate material within a fixed 1-m2 footprint. For natural intertidal reefs, oysters were sampled using a 1-m2 quadrat randomly placed on a reef with the number of quadrat samples determined as a function of reef area, and a maximum number of quadrat samples set at 10. When densities appeared likely to exceed 500/m2, a 0.25-m2 quadrat was substituted and subsequent oyster density estimates were standardized to 1 m2. All samples were hand-excavated to a depth of 10 cm. Natural intertidal oyster reefs were sampled during June, August, and October of 2014 and 2015. These sampling intervals followed several annual peak oyster recruitment pulses in North Carolina estuarine waters in May and a secondary peak in August, with the intention of tracking various oyster cohorts to quantify post-settlement growth and survivorship. The left valve length (LVL; distance from the umbo to the anterior margin of the shell) of all live oysters was measured to the nearest 1 mm with calipers.

Each site has an associated lat/lon coordinate -- this was updated in version 2 (2021-02-01) to be the same for all data points. The accuracy of the GPS was not adequate to provide more resolution with the data.