Dataset: Box Core Macrofauna Species Counts collected Oregon and Washington Shelf 2021-2022

At each station, samples were collected with a modified Grey-O’Hara 0.1 m² box core. One box core sample was taken at each station. Depth was recorded from the vessels’ echosounder at the time the box corer hit the bottom. Only samples with a penetration depth of at least 5 centimeters (cm) and no slumping or other evidence of disturbance (i.e., by washing) were accepted for processing. Approximately 80 milliliters (mL) of sediment were collected from the undisturbed surface layer for grain size analysis. Any organisms noticed in the sediment subsample at the time of collection were removed and placed in the organism sample jar. The remainder of the collected core was sieved onboard through a 1.0 millimeter (mm) mesh screen, and all organisms (both infauna living in the sediment and small epifauna which may have been on the surface – hereafter collectively called macrofauna) as well as debris retained on the screen were preserved in a mixture of 10% buffered formalin and seawater. Upon return to the Oregon State University (OSU) laboratory, samples were transferred to 70% ethanol. Organisms were then removed from the debris and sorted into major taxonomic groups using a dissecting microscope by trained laboratory staff/students. The residual portion (remaining debris after removal of organisms) of every sample was checked by a second lab personnel, and any found organisms were added to the sorted jars. Crustaceans, polychaetes, other worm-like creatures, and mollusks were then sent to contracted taxonomic experts. OSU staff identified the echinoderms.