BBC Wildlife Magazine

MALDIVES’ REEF RESCUE

- Jack Elliot Marley

Getting rid of predators such as crown-of-thorns starfish helps corals overcome bleaching.

Community efforts to remove predatory starfish are helping two coral reefs in the Maldives offset the worst impacts of bleaching, scientists say.

Steve Newman, head of conservati­on at ecotourism operator Banyan Tree, says that volunteers have removed more than 6,000 crown-of-thorns starfish and just over 1,000 pin cushion seastars since 2008.

“Removal efforts conducted by staff and guests were critical in maintainin­g high coral cover on both [the islands of ] Ihuru and Vabbinfaru,” Newman says.

Though both species are natural inhabitant­s of reefs in the Maldives, when coral is weakened by bleaching caused by higher sea temperatur­es, they exploit its fragile state and can eliminate it from an area.

The ‘reef rescue’ initiative began back in 2001 following a serious bleaching episode in 1998, and it continues today as regular, fortnightl­y trips to Ihuru and Vabbinfaru.

Banyan Tree says these act as an early warning system, helping conservati­onists to spot the onset of outbreaks before they overwhelm the coral.

Elsewhere in the Maldives the picture is much gloomier. On some sites where there has been no starfish removal, coral cover has been reduced by as much as 95 per cent following outbreaks. Other operators need to follow Banyan Tree’s approach, Newman says.

A survey carried out in 2016 found that higher-than-usual sea temperatur­es, exacerbate­d by the phenomenon of El Niño, had led to more than 60 per cent of reefs in the Maldives being hit by bleaching.

When temperatur­es rise, corals expel the algae with which they have a unique relationsh­ip, leading to bleaching and in many cases, the death of the coral polyps.

 ??  ?? Crown-of-thorns starfish exploit coral that has already been weakened by bleaching.
Crown-of-thorns starfish exploit coral that has already been weakened by bleaching.

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