Definition and Importance:
Coral diseases are illnesses that affect coral tissues, often caused by pathogens such as bacteria, fungi, or viruses. These diseases can lead to tissue loss and mortality, significantly affecting coral cover and reef health. Diseases infect corals when they are most vulnerable due to heat stress, water pollution (through wastewater and solid waste as well), and natural events such as storms and hurricanes that can bring new pathogens into the region.

Disease outbreaks continue to reduce coral populations worldwide. Understanding them and their relationships with other environmental factors is essential to predict disease outbreaks, and how coral populations will change, especially when combined with other stressors like bleaching and pollution.

One of the most lethal diseases we face right now is the Stony Coral Tissue Loss Disease. The disease outbreak has decimated coral populations especially of massive reef-building coral species, reducing habitat complexity and calcium carbonate production. It will likely be recorded as the most lethal disturbance ever in the Caribbean.

We find other diseases such as: white-band disease, yellow-band disease, and dark spot syndrome. 

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How Do We Measure it?
As with bleaching, coral diseases are monitored during benthic surveys, or quantifying the percent of corals infected with the same “bar drop” methodology. Divers visually inspect coral colonies, identifying and recording signs of disease, such as lesions, tissue loss, and discoloration. Data on the type, prevalence, and severity of coral diseases are collected to monitor trends and potential outbreaks. This information is crucial for understanding disease dynamics and implementing management strategies.