Coral Reef Monitoring

Coral Reef Monitoring

Coral reef health depends on complex relationships among the benthic, coral and fish communities. When changes occur in the dynamics of one of these components, the other components are affected and the whole relationship can be disrupted.

To understand reef condition, AGRRA examines multiple indicators of the benthic-coral-fish relationships. Since 1997, teams of reef scientists have assessed > 2,000 reef areas. The data have provided valuable baseline information for managers and government officials responsible for protecting coral reefs. The links below provide access to AGRRA monitoring protocols and data materials.

Coral Bleaching

Coral animals are sensitive to changes in sea water temperatures and other disturbances. Coral bleaching results when the symbiotic zooxanthellae (single-celled algae) are released from the original host coral due to stress. Visit the Coral Bleaching page to learn more.


Benthic organisms chosen for AGRRA Version 5 surveys are grouped by their ecological interactions with the reef-building corals and crustose coralline algae, including macroalgae, corals, other sessile invertebrates.



Corals create the reefs’ three dimensional structure, provide habitat for multitudes of other reef creatures and protect coastlines during storms. Coral condition is assessed by examining, by species, their size, bleaching state and extent of mortality from predation and disease.


The AGRRA protocol surveys fish that play an important functional role in reef ecology ( e.g., as carnivores, herbivores, Diadema predators), are important commercial fish species and or are likely to be affected by human impacts.

Diadema Response Network

A collaborative region-wide effort – the Diadema Response Network – has been formed to track and try to understand the cause of the early 2022 die-off of Diadema (and possibly other sea urchins).