Pacific Media Watch

11 March 2020

COOK ISLANDS: Conservationists rescue coral reefs from starfish scourge

Crown-of-thorns (COTS) starfish ... scourge of the coral reefs. Image: Khaled bin Sultan Living Oceans Foundation

By Sri Krishnamurthi
AUCKLAND (Pacific Media Watch): The Khaled bin Sultan Living Oceans Foundation (KSLOF) conservationists acted in the nick of time to save Cook Islands coral reefs from being devoured by the crown-of-thorns starfish (COTS).

Over five years, the Global Reef Expedition nearly circumnavigated the globe collecting data on the status of coral reefs in the Atlantic, Pacific, and Indian Oceans.

In 2013, the expedition arrived in the Cook Islands, where scientists worked closely with local leaders, government officials, and members of the Cook Islands Marine Park Steering Committee to study the reefs.

READ MORE: Poisonous starfish threatens Pacific coral reefs

Together, they completed more than 400 surveys of the coral and reef fish communities surrounding Rarotonga, Aitutaki, and Palmerston Atoll.

Global Reef Expedition: Cook Islands Final Report, released earlier this month, contains a comprehensive summary of the research findings from the expedition along with conservation recommendations that can help preserve Cook Island’s reefs into the future.

Scientists on the expedition found that many coral reefs in the Cook Islands were in good shape, with high coral cover and diverse and abundant fish communities.

For the most part, reefs in remote areas tended to be healthier than those near population centres. But while the reefs surrounding Palmerston Atoll were healthy, and the reefs in Rarotonga were doing alright, Aitutaki’s corals were being ravaged by an outbreak of crown-of-thorns starfish.

'Being eaten alive'
“When we arrived in Aitutaki, it was evident immediately that there was a problem. Reefs that should have been flourishing were being eaten alive before our eyes by thousands of starfish,” said Alexandra Dempsey, director of science management at the foundation and one of the report’s authors.

The reef was in crisis. In some places in Aitutaki, one of the more popular island destinations in the Cook Islands, crown-of-thorns starfish had damaged 80-99 percent of coral on the seafloor.

“We couldn’t help but intervene.”

Over the course of a few days, scientific divers on the Global Reef Expedition collected 540 COTS from reefs around Aitutaki.

The starfish were collected by hand, a daunting task as the starfish are covered in large venomous spines. Scientists returned to the reefs in 2015 to assess the damage and remove any remaining crown-of-thorns starfish.

Although the reefs have likely changed since then, reefs in the Cook Islands showed many signs of resilience.

When scientists returned to Aitutaki, they noted that healthy fish populations and a diverse coral community allowed new coral to settle and grow on damaged reefs, beginning the process of recovery.

Based on their experience, the scientists created a best-practices guide for dealing with future COTS outbreaks and shared their findings with government officials in the Cook Islands.

Optimistic about future
Despite the damage done by COTS in Aitutaki, the report’s authors are optimistic about the future of Cook Islands’ reefs. “With continued efforts to protect and preserve their reefs, coral reefs in the Cook Islands could become some of the best in the South Pacific,” said KSLOF marine ecologist Renée Carlton.

The Cook Islands is regarded as a global leader in marine conservation, most notably for establishing Marae Moana marine park – the largest in the world - and expanding it to include all of their waters. The development of a zoning plan for the marine protected area is currently underway to determine which activities will be allowed where.

The Foundation produced an award-winning film, Mapping the Blue, which shows how these maps were made and illustrates how they can inform marine spatial planning efforts in the Cook Islands.

The film stars former Kiwi international rugby league winger Kevin Iro now Marae Moana ambassador and conservationist.

“We are excited to receive the report and are most appreciative of the work done by Living Oceans Foundation,” said Iro.

“This report will definitely help with our current marine spatial planning of the Marae Moana and it also demonstrates that government and non-government organisations can work cooperatively to better understand our ocean environment.”

A similar study and work to rid coral of COTS was done in Vanuatu three-years ago.

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