Clouds of bubbles generated by breaking waves were detected with a vertically directed high-frequency echo sounder mounted on a submarine. Bubble concentration was inferred from a simple model of the bubble size distribution. The vertical and horizontal distribution of clouds is discussed in terms of wave-breaking processes, air-sea temperature differences, and subsurface motions are thought to modulate the bubble concentration. Mean vertical profiles of bubble concentration decreased roughly exponentially with depth, with e-folding depths between 0.7 and 1.5 m. The mean bubble concentration at the surface, N¿0, was found to increase with the wind speed measured at 10 m above the surface, U10, as N¿0~U103.0¿0.3. Various upper ocean dynamical processes are discussed in terms of their effects on the shapes and spacing of bubble plumes. The observations provide only weak evidence to support relationships between plume spacing and surface wave-breaking events and between plume spacing and the expected scale of Langmuir circulation. ¿ American Geophysical Union 1987