These data represent the abundance of phytoplankton imaged underway along the NES-LTER Transect during the winter 2018 cruise EN608. Images were obtained on board by an Imaging FlowCytobot (IFCB) sampling at approximately 20-min intervals from seawater supplied from 5-m water depth. Data are provided for the subset of images during the cruise that were very near the north-south transect along longitude 70 53' W. Identifications to morphological groups, matched to the lowest taxonomic level, were done manually for over a quarter million images. Data are provided by taxon. Two tables are provided: one data table that summarizes the occurrences by taxon per sample and a table to match taxon names to the World Register of Marine Species. Sample identifiers are linked to images served by an external repository.