Dataset: Effects of intra-population variation in dogwhelk drilling on the abundance and size of Mytilus californianus mussels

Dogwhelks (Nucella canaliculata) were reared in the laboratory on four early-life diet treatments for the first 3 months of life. In July of 2021, adult dogwhelks were outplanted to field cages (stainless steel mesh cages with removable lids that were bolted to the substrate) at Bodega Marine Reserve. The plots within the cages when the dogwhelks were outplanted were at a mid-successional stage, containing a mix of acorn barnacles, gooseneck barnacles, and a few small mussels. The cages were in a block design with five cages placed near each other. The dogwhelks outplanted to a given block were from the same family (dogwhelks from the same egg capsule cluster were referred to as a family of snails) with each cage getting dogwhelks that were reared on one of the four early life diet treatments, plus one cage was a reference cage that did not get any dogwhelks. The dogwhelks remained in the cages for the next year until August 2022 when the dogwhelks and all of the mussels within the cages were collected and brought back to the laboratory. The organisms were sorted, the number of mussels present in each cage was counted, and their lengths (along the anterior to posterior axis) were measured. Very small mussels (<10 millimeters) were excluded, as these mussels were difficult to evaluate accurately.