This shapefile contains the lines of navigation used by vessels conducting bathymetric data collection as part of the Monterey Bay Aquarium Research Institute (MBARI) Multibeam Survey in California during June of 1998. MBARI completed surveys of selected areas offshore of the Monterey Bay California using the recently developed Simrad EM300 multibeam system to collect bathymetry and backscatter data. MBARI contracted with C&C Technologies to run the system because they had installed the EM300 system on a contracted vessel, the M/V Ocean Alert. The 30 kHz EM300 system, because it is hull-mounted, allowed MBARI to collect georeferenced high-resolution bathymetric and sidescan data at high speeds in water ranging from shelf to abyssal depths.This collection of data provides documented layers of of the Monterey Bay to persons/institutions of interest throughout the research and educational communities. These maps help define the geological variability of the seafloor and provide a detailed framework for future oceanographic research, monitoring, and management activities.