Coral reefs are under increasing pressure. Threats from climate change, overdevelopment, increasing population, and overfishing have a compounding effect to weaken coral resilience, making them more vulnerable when ocean temperatures rise and coral bleaching sets in.
But the more we learn about corals the more science emerges of the positive local impacts coral reef management, or tending to coral gardens can produce.
Coral restoration can work to selectively harvest and propagate thermally tolerance coral genotypes and new research from Duke University suggests that removing coral predators such a the corallivorous snail Coralliophila abbreviata can further aid in reducing stress and increasing coral resilience throughout a bleaching event.
A study from Florida tested this theory of snail removal on Caribbean brain corals (Pseudodiploria and Diploria species). The team tested the removal of the snail which feeds on coral tissue, from Caribbean corals before a severe, climate-related warming event.
“First, we surveyed six reefs in the Florida Keys, USA to determine natural densities the number of snails per coral colony of the snail Coralliophila abbreviata—a significant predator of numerous reef-building corals in the Caribbean”.
They found that snail infestation was disproportionately higher on brain corals than other more common species 40% of brain coral colonies, compared to a low abundance 2.6% on their more preferred prey (Acropora and Orbicella species), this is possible due to the increasing loss of these coral species in recent generations.
If the snails are left to feed on the coral colony they munch their way along the tissue draining the coral of energetic resources, even in portions of the coral colony distant from the site of predation. And these snails often feed in groups increasing tissue damage as the remaining tissue dwindles in size.
The research team from Duke showed that removing invertebrate, such as the coral eating snail enhanced coral colony resilience, especially to temperature stress. The corals were more able to recover after heat-induced bleaching.
No only does the snail removal reduce stress on corals, but since the snail are covered in algae, they can bring in harmful algae which can easily overtake weaken or dead coral surfaces.
While we wouldn’t suggest everyone goes out and start picking snails off corals… when these predators snails are removed from coral species by coral reef managers and trained professionals it can have help to protect corals from climate change-related stress.
This highlights the importance or local management and having someone employed to tend to coral gardens especially in vulnerable areas or during times of high temperatures and stress.