Distribution and mapping of the snail Cerithideopsis (Cerithidea) californica at Carpinteria Salt Marsh, California USA, June to August 2012

We collected detailed spatial data on the density and size distribution of intertidal snails as part of a broader effort to understand food webs in California estuaries. The survey area was Carpinteria Salt Marsh, California USA, which comprises 9 Ha tidal channels, 2 Ha salt flats, 17 Ha upland habitat, 6 Ha tidal pans, 52 Ha vegetated marsh, 2 Ha tidal flats. Using nearly 4,000 transects in potential snail habitat, we mapped snails throughout the estuary. Specifically, we systematically placed transects at intervals stratified within targeted habitat types: channels, pans, or marsh (or planar habitat that was mixed marsh and pan). At a quarter of the quadrats, we also estimated snail size-frequency distributions. Because we recorded the location of each quadrat, these data can be used to map the distribution of snails throughout this estuary.