In the Cape Shore region of Delaware Bay, New Jersey, USA, about 2 km of intertidal oyster farms overlap spawning habitat for the Atlantic horseshoe crab (Limulus polyphemus) whose eggs provide food for several migratory shorebirds of conservation concern. Oyster farming can modify sediments through deposition of organic and inorganic byproducts. This may alter habitat for infauna, which are prey for the aforementioned animals. This study examined whether oyster farms in Delaware Bay alter organic and inorganic carbon content of sediments and infauna abundance. Surveys were conducted in two paired farm-control plots (90x60 m) across a 1 km stretch of tidal flats. In Spring 2021 and 2022, 156 sediment cores (218x20 mm) were collected to estimate infauna diversity and abundance. In July 2022, 80 duplicate sediment cores (16x20 mm) were collected to determine relative proportions of organic and inorganic carbon across each plot.  The effect of farms on infauna abundance varied among taxa and years. Total abundance was significantly higher in the farms in 2022, suggesting a positive effect of oyster farms. Additionally, polychaete abundance was significantly greater in farm plots in both years.  Results of a generalized linear mixed effects model indicated significantly higher inorganic carbon levels in farm sediment, but no difference in organic carbon. These results indicate that oyster farms can alter sediment composition and infauna abundance, but further research is needed to determine if there is a direct relationship between sediment composition and infauna.

Primary Presenter: Simon L'Heveder, University of Edinburgh (simonlheveder27@gmail.com)

Authors:

Simon L'Heveder, The University of Edinburgh  (simonlheveder27@gmail.com)

Elizabeth Bouchard, Rutgers University  ()

David Bushek, Rutgers University  ()