Coral Predators
by Fahmi, AMD-B’s 2024 Divemaster Intern
Coral reefs are vibrant ecosystems, and like any environment, they have species that interact in different ways. Some creatures feed on corals as part of the natural balance of life on the reef. While it might seem concerning at first, this predation is usually just a part of maintaining a healthy ecosystem.
Key Coral Predators
Crown-of-Thorns Starfish (COTS):
The Crown-of-Thorns Starfish is one of the most well-known coral predators. These spiny creatures feed on coral polyps, digesting the living tissue and leaving behind the skeleton. While they’re a natural part of the ecosystem, outbreaks can lead to significant damage to coral reefs.
Parrotfish:
Parrotfish are famous for grazing on coral. Their strong, beak-like teeth allow them to scrape away pieces of coral, which they digest and later excrete as sand. While this sounds harmful, they also help control algae, preventing it from overtaking the reef. In moderation, their coral consumption is part of the reef’s healthy balance.
Drupella Snails:
These small snails feed on coral polyps and can leave marks on the coral. They usually don’t cause widespread damage but can be a part of the natural predation cycle on reefs.
Butterflyfish:
These colorful fish feed on soft corals and polyps. Their impact is relatively minor, and they’re another example of how coral predation is part of the reef’s life cycle.
When Populations Get Out of Control
In most cases, coral predators are just a part of reef life. However, when their populations grow too large, they can cause significant harm. One example is the Crown-of-Thorns Starfish outbreaks. These outbreaks occur when the starfish population spikes, often due to factors like pollution or overfishing of their natural predators. During an outbreak, the starfish can consume large areas of coral, leaving behind dead coral skeletons.
Such outbreaks can severely weaken coral reefs, making them more vulnerable to other threats like climate change, ocean acidification, and storms. When the balance shifts too far, the reef can struggle to recover.
