Number and sizes of abalone and urchin recorded during dive surveys at specially designed recruitment modules (RMs) deployed at rocky subtidal reef at Van Damme State Park, Mendocino County, California, USA from August 2001 to August 2023

An important facet of the Kelp Forest Monitoring project is sampling recruitment of juvenile abalone and sea urchins. Specially designed recruitment modules (RMs) made of stainless steel and filled with ½ concrete cinder blocks as habitat were bolted to the rocky subtidal reef at Van Damme State Park, Mendocino County, California. Twelve RMs were deployed at 10 to 12 meters depth in three groups of four in August of 2000. They were allowed to season for a year before surveys began in August 2001.

Each August, SCUBA dive teams collected and measured the organisms inside the modules. The data associated with this dataset are the number and sizes of red abalone (Haliotis rufescens), pinto abalone (H. kamtschatkana), flat abalone (H. walallensis), red sea urchins (Mesocentrotus franciscanus), and purple sea urchins (Strongylocentrotus purpuratus). Data are presented in tabular format with a row for each RM each year.