According to Bacteriophage Distributions and Temporal Variability in the Ocean’s Interior mBio Nov/Dec 2017 Volume 8, e01903-17:
Phages have been
shown to kill hosts at rates of up to 20 to 40% of the total population per day,
potentially strongly impacting bacterioplankton populations (7,8).
Where reference 7 is Ecology of prokaryotic viruses. FEMS ...