Patterns of mass mortality among rocky shore invertebrates across 100 km of northeastern Pacific coastline

Survey data describing densities of Strongylocentrotus purpuratus (purple sea urchin) in subtidal and intertidal habitats before and after a mass mortality event along the coast of north-central California in the northeastern Pacific Ocean. For details regarding sampling methods and context, see Jurgens et al. 2015, "Patterns of mass mortality among rocky shore invertebrates across 100 km of northeastern Pacific coastline."