Think we will have to agree to disagree on this one. You are saying that algae takes over when coral cover decreases, I am saying that increased algae levels cause the loss of coral cover, completely opposite. Increased overfishing lets the algae grow unchecked, and the resultant increase in dissolved organic carbon fuels the increase in microbes and pathogens which kill the corals. Pollution etc just adds to the problem of an already weakened ecosystem.
The reefs have been in decline ever since the colonial days but modern technology has made it ridiculously easy to remove huge numbers of fish from the seas.
Forgive my ignorance but I do not know what the numbers for the doc levels you posted are measured in.
I intend to try and contact forest lowher to get his input into this matter.
Correct me if I am wrong but the decline of the Caribbean reefs in the 80s was in a major part caused by a 99% collapse in the sea urchin population from a pathogen, which allowed the algaes to overrun the reef, combined with overfishing of the fish which may have kept it's levels in check.