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Hopes for our resilient reefs

Saturday March 07, 2020 Written by Published in Weekend
Scientists on the expedition collect crown of thorns starfish to limit the damage of the outbreak in Aitutaki. 20030636 Scientists on the expedition collect crown of thorns starfish to limit the damage of the outbreak in Aitutaki. 20030636

A long-term study of the coral reefs of Rarotonga, Aitutaki and Palmerston shows promising signs of recovery – though Crown of Thorns starfish remain a worry on Aitutaki. 

In 2013, scientists and researchers from the Khaled bin Sultan Living Oceans Foundation found the coral reef on the ocean floor in Aitutaki was in crisis.

Crown-of-thorns starfish had damaged 80-99 per cent of coral on the seafloor.

The team on the expedition knew they had to intervene and removed hundreds of the starfish by hand – a strenuous task given they are covered with venomous spikes.

When the team returned in 2015, reefs in the Cook Islands showed promising signs of repair and resilience.

With continued protection, coral reefs in the Cook Islands will continue to flourish for generations to come, according to a report released this week by the Foundation.

The Khaled bin Sultan Living Oceans Foundation has published their latest findings from the Global Reef Expedition—the largest coral reef survey and mapping expedition in history.

The Global Reef Expedition: Cook Islands Final Report contains critical information on the health and resiliency of coral reef ecosystems in the Cook Islands.

It provides scientists, policymakers, and stakeholders with invaluable information they can use to protect and restore these fragile marine ecosystems. 

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

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

Scientists on the research mission also created over 400 square kilometres of detailed marine habitat and bathymetric maps of these three island areas.

This information can help managers identify priority sites for conservation action and track changes to the reef over time.

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

Cook Islands international rugby star and conservationist Kevin Iro starred in the movie and helped to establish the Cook Islands marine park, Marae Moana—the largest marine protected area in the world. 

“We are excited to receive the report and are most appreciative of the work done by Living Oceans foundation,” said Marae Moana Ambassador Kevin 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.” 

The report 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. 

“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,” Foundation Director of Science Management and one of the report’s authors Alexander Dempsey said.

“We couldn’t help but intervene.” 

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

Scientists returned to those reefs in 2015 to assess the damage and remove any remaining crown-of-thorns starfish.

Although the reefs have likely changed since then, they showed many signs of resilience.

When scientists returned to Aitutaki, they noted 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 crown-of-thorns starfish outbreaks and shared their findings with Cook Islands government officials. 

Despite the damage done 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 Foundation marine ecologist Renée Carlton. 

Cook Islands is regarded as a global leader in marine conservation, most notably for establishing Marae Moana marine park and expanding it to include all their waters.

The development of a zoning plan for the marine protected area is currently underway to determine which activities will be allowed where. 

Foundation chief scientist Sam Purkis said it was a privilege to work in the Cook Islands, which turned out to offer some of the more vibrant reef systems encountered on the Global Reef Expedition.

“It was particularly reassuring to see that the conservation initiatives already in place in the country, such as the widespread use of marine protected areas and reserves, are paying dividends,” he said.

 

“It is our sincere hope that the habitat and benthic maps that we have produced for the Cook Islands from satellite, along with the extensive portfolio of field data, will serve to bolster these ongoing efforts and even more ambitious conservation actions.”