Dataset: E. depressus - parasite study - field survey (Oecologia, 2014)

We tested the effects of barnacle (Loxothylaccus panopei) parasite infection on the interaction between the flat-backed mud crab (Eurypanopeus depressus) and its prey, the scorched mussel (Brachidontes exustus). All animals used in experiments were collected from intertidal oyster reefs in tidal creeks throughout North Inlet estuary (33°20'N, 79°10'W), Georgetown, South Carolina, USA. North Inlet is a relatively pristine salt marsh consisting of ocean-dominated tidal creeks with a high average salinity (~34 ppt) and a diurnal tidal cycle (Dame et al. 1986). We ran experiments in the screened-in, outdoor wet laboratory at the adjacent Baruch Marine Field Laboratory. The field survey of parasite prevalence was also conducted in intertidal reefs throughout North Inlet. Experiments and field sampling were conducted from June through August 2012.

Field survey:
We surveyed the prevalence of the barnacle parasite in flatbacked mud crabs in the field. This survey allowed us to determine the overall rate of parasite infection in crabs, as well as some intrinsic factors associated with infection. We sampled crabs in haphazardly placed quadrats (0.25 m2) in intertidal oyster reefs throughout North Inlet. Nine oyster reefs were sampled in total and six quadrat samples were taken from each reef (a total of 54 quadrat samples). All quadrat samples were taken from the upper intertidal sections of reefs. Within each quadrat, all E. depressus were removed by hand and their carapace width, sex, and infection status were recorded. We recorded the presence of crabs below 5 mm, but were unable to accurately measure the carapace width or discern the sex of these crabs.