You might not think an animal made out of stone would have much to worry about in the way of predators, and that’s largely what scientists had thought about coral. Although corallivores like parrotfish and pufferfish are well known to biologists, their impact on coral growth and survival was believed to be small compared to factors like heatwaves, ocean acidification and competition from algae.
But researchers at UC Santa Barbara have found that young corals are quite vulnerable to these predators, regardless of whether a colony finds itself alone on the reef or surrounded by others of its kind. The research, led by doctoral student Kai Kopecky, appears in the journal Coral Reefs.
Kopecky and his co-authors were curious how corals can reemerge following large disturbances like cyclones and marine heatwaves, which periodically devastate the reefs of Mo’orea, French Polynesia, where the research was conducted.
«Mo’orea is prone to big heat shocks, storm waves, cyclones and predatory sea star outbreaks,» said co-author Adrian Stier, an associate professor in the Department of Ecology Evolution & Marine Biology and one of Kopecky’s advisors. «It just wipes the slate clean in terms of coral death. And sometimes, just a few years later, you can swim around and see thriving life. We’re still really curious about what allows these ecosystems to bounce back.»
Scientists had implicated predators in shaping coral population dynamics, but there hadn’t really been many direct studies. «People who study coral reefs have thought a lot about the supply of new babies coming from elsewhere, or limitation by the amount of nutrients, or competition with algae as important drivers of coral recovery,» Stier continued. «But there hasn’t been as much done on the importance of predators as a limiting factor.»
After reviewing the literature on coral growth, mortality and predation, Kopecky decided to focus on the effects predation and density had on young coral colonies.
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Materials provided by University of California — Santa Barbara. Original written by Harrison Tasoff. Note: Content may be edited for style and length.