GROW Tile ms data

Eastern oyster recruitment and size on Oyster Castles (OC) and GROW Reef Tiles (GT) were assessed three times over 25 months in multiple locations with varying salinity. Four sites in the Chesapeake Bay region were examined: Cherrystone Inlet, Mockhorn Bay (eastern shore), Elizabeth River and, Lynnhaven Bay (western shore). Our hypothesis was that GROW Tiles would allow for higher oyster densities and larger oysters than the Oyster Castles due to habitat heterogeneity (varied orientation of the surfaces) and their special composition with concrete that is formulated to match oyster shell (GROW 2021). Additionally, we hypothesized that oyster densities would differ among sites due to abiotic stressors such as salinity, relative shoreline height, wave exposure. At each site, ten OC and ten GT were randomly placed parallel to shore in the intertidal zone in May 2019. Sites were sampled non-destructively in October 2019, July 2020, and June 2021. A quadrat (0.30 m x 0.30 m) was placed on top the structure, dividing the structure into four quadrants, and one random quadrant was chosen to count and measure oysters for shell height and mortality status. Data on oyster height and mortality status for each of the sites and years are shown in the dataset columns. Data from each year and combined data (2019-2021) were analyzed using the response variables oyster density and shell height along with combinations of the factors year, site, and substrate type. Both substrate types (OC and GT) had high oyster recruitment (>400 oysters m-2). At 25 months post-deployment, mean oyster densities differed significantly by substrate, with 553.3 ± 59.8 (SE) oysters m-2 on OC and 423.0 ± 57.0 oysters m-2 on GT (24% higher on OC), associated with 27% higher surface area on OC. Oyster densities differed by site, with highest densities in Mockhorn Bay. Growth was ~60-70 mm over the 25 months, and oysters were smallest at the highest-salinity and highest-density site. Mean oyster shell height was greater on GT (61.7 ± 2.2 mm) compared to OC (57.3 ± 2.1) over the time frame.