Elevated predation on crown-of-thorns starfish in no-take marine reserves

Predator removal can destabilise and devastate ecosystems, particularly if a species released from top-down control can itself fundamentally alter the system. On Indo-Pacific reefs, coral-eating crown-of-thorns starfish (CoTS, Acanthaster spp.) threaten ecosystem function and resilience due to their propensity to undergo destructive population outbreaks that cause widespread coral loss. One of the foremost hypotheses to explain these outbreaks centres around the overfishing of their putative predators. Notably, outbreaks of CoTS seem to be less prevalent on reefs protected from fishing, but the risk of predation has never been quantified. Here, we show that the predation risk for CoTS inside no-take marine reserves on Australia’s Great Barrier Reef is 3.6- and 2.8-times higher than in areas where fishing is permitted and limited, respectively. Moreover, the elevated predation risk inside no-take reserves is directly attributable to a single fish species, the spangled emperor (Lethrinus nebulosus), a fishery species that shows up to 6.3-times greater biomass on no-take versus fished reefs. These findings may explain how no-take reserves protect reefs from CoTS outbreaks and highlight targeted conservation of L. nebulosus as a promising management strategy to mitigate reef degradation by CoTS outside of no-take reserves.

Current Biology

Current Biology

36

1879-0445

N/A

3

2