Fourteen moorings were deployed across the midlatitude North Pacific 165°E to 152°W, for approximately 2 years during 1983–85. Ten mooring sites had previously been occupied at similar latitudes (30°–40°N nominal) for roughly two years (1980–82) along 152°E. Taken together, these observations form the basis for the first systematic basinwide zonal exploration of the eddy field based on moored instrument techniques in the midlatitude North Pacific along the Kuroshio Extension System and North Pacific drift. Eddy kinetic energy (KE) at abyssal depths decays sharply moving east from 152°E, and has decreased by a factor of 4 by 165°E. There is a plateau in abyssal KE of about 10 cm2 s−2 across the Emperor Seamounts from 165° to 175°E. Abyssal KE drops to roughly 5 cm2 s−2 at 175°W and 1 cm2 s−2 at 152°W, for a total decay of a factor of about 50 across the midlatitude North Pacific. Upper level KE decreases by a total of roughly two orders of magnitude (approximately 103 to 101) from 152°E to 152°W. ... Abstract Fourteen moorings were deployed across the midlatitude North Pacific 165°E to 152°W, for approximately 2 years during 1983–85. Ten mooring sites had previously been occupied at similar latitudes (30°–40°N nominal) for roughly two years (1980–82) along 152°E. Taken together, these observations form the basis for the first systematic basinwide zonal exploration of the eddy field based on moored instrument techniques in the midlatitude North Pacific along the Kuroshio Extension System and North Pacific drift. Eddy kinetic energy (KE) at abyssal depths decays sharply moving east from 152°E, and has decreased by a factor of 4 by 165°E. There is a plateau in abyssal KE of about 10 cm2 s−2 across the Emperor Seamounts from 165° to 175°E. Abyssal KE drops to roughly 5 cm2 s−2 at 175°W and 1 cm2 s−2 at 152°W, for a total decay of a factor of about 50 across the midlatitude North Pacific. Upper level KE decreases by a total of roughly two orders of magnitude (approximately 103 to 101) from 152°E to 152°W. ...