The vertical flux of pigmented fecal pellets was measured for periods of 4 h or less with closely spaced sediment traps. The settling of the nighttime injection resulting from macrozooplankton grazing activity could be monitored as the pellets settled through the water column. Sinking rates of fecal pellets showed a range of 31 – 122 m d−1 with an average of 87 m d−1. Longer term experiments show that the vertical phaeopigment flux is conservative, and that there is no significant loss of pigments en route to the sea floor. In Dabob Bay, coprophagy in the water column is most likely a minor consideration. The amount of chlorophyll sinking out of the euphotic zone usually represents <1% of the standing crop, and is usually only 5% or less than the phaeopigment flux. This suggests that grazing is the predominant process accounting for the major loss of chlorophyll from the water column.