Drupella are snails with shells up to 5 cm long that are covered in small spikes or bumps. The shells appear off-white to brown but can sometimes be pinkish to purple when overgrown with red coralline algae. They are commonly found living on corals in reefs throughout the Indo-Pacific and are becoming more common on the fringing reefs around the Whitsunday Islands.

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Drupella eats live coral tissue by stripping the tissue from the coral skeleton and leaving white feeding scars that can quickly become covered by algae. Feeding scars can have detrimental effects on coral growth. Drupella prefer to feed on fast-growing species with complex, branching growth forms such as Acropora and Pocillopora, but will feed on most corals in the absence of their preferred species

 

 

 

 

 

 

 

 

 

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DRUPELLA OUTBREAKS

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Outbreaks of Drupella can cause significant damage to coral reefs. For example, in Western Australia and Japan, Drupella outbreaks have drastically reduced coral cover.  But, similar to crown-of-thorns starfish, Drupella may also help to maintain coral diversity by grazing down faster-growing corals (e.g., Acropora/staghorn) to allow for slower-growing species to become established.

 

WHAT CAUSES DRUPELLA OUTBREAKS?

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It is unclear what causes outbreaks of Drupella, but human impacts such

as terrestrial run-off, overfishing of Drupella predators, and increased reef

damage have been suggested as potential causes. 

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Others suggest that changes in water temperature and salinity contribute

to outbreaks. A study of Drupella in Hong Kong showed that significantly

more Drupella were attracted to corals that were stressed and in low

salinity water than to unstressed corals. Similarly, corals on the Great

Barrier Reef damaged by cyclone Ivor in 1990 were more significantly

affected by Drupella. More recent studies have also noted increased

outbreaks of Drupella on corals affected by the disease. 

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CONTROL OF DRUPELLA

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As part of the Tourism Industry Activation and Reef Protection Initiative,

Red Cat Adventures has been awarded a permit to help eradicate any

Drupella that are found while doing the Reef Health Impact Surveys. 

To remove Drupella they are collected by hand or using tweezers.

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