Seabird biomass distribution across the North Pacific

Distribution of seabird biomass (kg/km²) across the North Pacific calculated from average seabird densities on transects in the North Pacific Pelagic Seabird Database (NPPSD) Ver. 2.0. Samples were binned into 100 x 100 kilometer cells, masses summed for each species and then summed across species to yield total biomass, which was then divided by total sampled area to calculate average biomass density in each cell.