What are the major threats to corals?

Stony coral tissue loss disease (SCTLD) is a deadly coral disease first reported in 2014 off the coast of Florida. View a detailed image and read a description of SCTLD.

Coral abnormalities were first recognized in Caribbean reefs in the mid-1960s, and black band disease was first described in 1973. Since then, the number of new coral diseases, the extent of reef areas impacted, and the frequency of large-scale disease outbreaks have risen dramatically worldwide. Today, there are approximately 40 coral diseases that affect more than 200 species of hard coral in the Caribbean and IndoPacific.

What are coral diseases? A disease is any deviation from, or interruption of, the normal structure or function of any body part, organ, or system that has a distinct group of observable symptoms whose cause(s) may be known or unknown. Coral diseases are often observed as either color change or skeletal damage, and may be accompanied by tissue loss.

Coral diseases generally occur in response to biological stressors, such as bacteria, fungi, algae, and viruses, as well as non-biological stressors, like increased water temperatures, ultraviolet radiation, and pollutants. One type of stress may exacerbate another.

White Band Disease (WBD) is a common tissue loss disease that affects two species of Caribbean coral. View a larger image and read a description of WBD.

With the exception of severe wide-spread disease outbreaks, most reefs have only about 3-5% of their corals affected by disease at any given time.

The tools used to address coral diseases include prevention, response, and recovery. Federal, state, and local governments as well as academic institutions and nonprofit organizations all work together, to determine the type and extent of a disease affecting the corals in an area, what may be causing it, and what they can do to try and return the corals to health.