Controlled Starfish Feeding May Aid Reef Biodiversity
A University of Sydney study in Ecology and Evolution links moderate crown-of-thorns starfish predation to greater coral diversity on the Great Barrier Reef.
Updated on Nov. 1, 2026 in Environmental
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University of Sydney researchers report that crown-of-thorns starfish at controlled levels may support biodiversity on the Great Barrier Reef. Scientists stress the benefits apply only to controlled populations, not to major outbreaks.
Why it matters
Starfish outbreaks have damaged reefs repeatedly, and declining natural predators have worsened their impact. The findings suggest conservation efforts should manage outbreaks while protecting the species' natural predators rather than eliminating starfish entirely.
Researchers observed that coral tissue survived about 75 percent of starfish feeding events at protected sites, based on analysis of feeding scars and remaining tissue. The reef has experienced four major outbreaks since the 1960s, and the study does not address how survival rates shift during those outbreaks.
The players
University of Sydney
A leading Australian research university whose researchers conducted the study on starfish and reef biodiversity.
Dr. Shawna Foo
A researcher who led the study analyzing starfish feeding scars and coral tissue at protected reef sites.
The details
Researchers led by Dr. Shawna Foo studied the reef at One Tree Island Research Station, where healthy fish populations keep starfish numbers under control. Starfish selectively feed on fast-growing Acropora coral, opening space for slower-growing Montipora and Porites corals to establish, a pattern consistent with the intermediate disturbance hypothesis.
Timeline
Since the 1960s, the Great Barrier Reef has experienced four major crown-of-thorns starfish outbreaks.
Big Picture
The findings align with the intermediate disturbance hypothesis, which holds that moderate disturbance can increase species diversity in a community. Applied to the Great Barrier Reef, moderate starfish feeding appears to open space that lets slower-growing corals establish alongside fast-growing Acropora.
Managing starfish outbreaks while protecting natural predators could shape reef conservation decisions that affect coral cover and marine life. The study's findings apply only to controlled populations, so outbreak management remains a separate priority.
The takeaway
Moderate predation can strengthen reef diversity, but the benefit disappears when starfish populations surge. Protecting the natural predators that keep starfish numbers in check is a practical step toward healthier reefs.
Further reading
For more on reef ecosystems and ocean conservation, explore the Environmental section.
Source note: This article includes information reported by RocketNews.
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