A SEASAT synthetic aperture radar (SAR) image taken over the Gulf Stream region shows streak-like patterns. The physics of their generation and interaction with the Gulf Stream are disputed. This study seeks a convincing interpretation for the SAR imagery patterns. Bathymetric maps show that the sea floor area beneath the streaks is the northeast Hoyt Hills, where isolated seamounts with the heights of 20 to 140 m above the background sea floor are distributed. All the SAR imagery streaks originate from these seamounts and extend downstream. Thus the SAR imagery streaks are interpreted as surface roughness imprints of the seamount wakes. Hydrostatic flow dynamics of the generation of wakes on the lee side of a solid obstacle is used to explain the generation mechanism and internal structure of the seamount wakes. The analysis indicates that boundary conditions and hydrodynamic conditions are favorable for the generation and vertical propagation of the seamount wakes to the upper layer.