Data files and R scripts are for the analyses that are presenting in an article that is under revision for Biology Communications. The title of the article is: Declines over the last two decades of five key invertebrate species found on rocky intertidal shores throughout the western North Atlantic. The three data files contain the abundances of four gastropod species and the recruitment of barnacles and mussels from 1997 to 2018, monthly temperature data from three buoys from 2001 to 2018, and pH and aragonite saturation state from 1997 to 2014. R scripts include details of Bayesian estimates for Poisson regressions of species over time, clean-up of environmental data, imputation of missing environmental data and analyses of species versus environmental parameters.