Figure 1. Conceptual model of the effects of fish excretion on coral reefs.

Conceptual diagram of the proposed influence of fish excretion on corals and macroalgae in both coral-dominant and coral-depauperate reefs. Line thickness represents the strength of the interaction. Size of the words for fishes, corals, and macroalgae represents their relative abundance in the community in either scenario. The transition from coral-dominant to coral-depauperate could have resulted from any disturbance such as coral bleaching or a hurricane. Herbivory per unit area is assumed to decline from the coral-dominant to the coral-depauperate scenario, as a decline in coral cover results in more open space that herbivores are required to graze to keep algal populations low.