|KOLONIA, Pohnpei - The first part of a comprehensive survey to check the health of Pohnpei's coral reefs has found that while corals on some reefs are in good condition, many reefs inside Pohnpei's lagoon are being stressed by sediment washing off the land. The survey has also found many crown-of-thorns starfish which are eating the corals.
From June 28 until July 16, coral specialists Mr. Emre Turak from France and Dr. Lyndon DeVantier from Australia are assessing the health of Pohnpei's reefs and looking for new coral species. "There is a lot of sediment washing off the land and settling on corals. This extra sediment load in the water is stressing the corals," said Mr Turak. "It is also likely that nutrients are running off the land with the sediment, and help to provide extra food for the young crown-of-thorns starfish. This means that more starfish than usual are growing to become adults."
"Some fish, such as the kadek and the medi, will eat young crown-of-thorns starfish and help to keep starfish populations under control. However, we have not seen many of these fish on Pohnpei's reefs," he said.
"The poor water quality and low numbers of fish means that there is a thriving community of crown-of-thorns starfish eating many of the corals," said Mr Turak. A previous report found crown-of-thorns starfish on reefs in Pohnpei in the 1970s.
"From the damage that we've seen on some reefs, it appears that the starfish populations have become chronic - and that there always low numbers of crown-of-thorns starfish living on Pohnpei's reefs. The starfish are changing coral communities so that some corals are disappearing and others are becoming more common."
Turak and DeVantier have found some uncommon corals such as Acropora pichoni, Acropora simplex and Acropora rongelapensis growing in rich coral communities along the western side of Pohnpei's coast. They believe these communities would have been more common in Pohnpei before land use practices caused extra sediment to flow into the lagoon.
Turak and DeVantier advise that improved land use and fisheries management are needed to protect Pohnpei's reefs, which form the basis of all inshore fisheries.
Pohnpei has established 11 Marine Protected Areas to help preserve its coral reefs. These MPAs will help to boost fish numbers in some areas of Pohnpei which may reduce the numbers of crown-of-thorns starfish.
On the positive side, Turak and DeVantier have found corals growing in Pohnpei like they have not seen anywhere else in the world. They found Porites corals growing in towers that they estimated to be at least two centuries old. They have also found many corals growing thousands of kilometres beyond where they are known to live. At Ant Atoll, Turak and DeVantier have found a different community of corals than they have found growing around Pohnpei.
Emre Turak is an experienced coral ecologist who specialises in rapid assessments of coral reefs. He has undertaken rapid assessments of the coral reefs of the Solomon Islands, Papua New Guinea, Indonesia and Australia.
Lyndon DeVantier has extensive experience in biodiversity and ecological assessment and is a world leader in developing monitoring and surveying techniques for coral reefs. He has worked extensively on reefs in Vietnam, Hong Kong, the Red Sea, Yemen and Australia.
"Information from the survey is vital for government agencies, non-government organizations and communities to assist conservation efforts and better manage these critical resources," says Mr Willy Kostka of the Conservation Society of Pohnpei who is leading the survey. "The survey can also be a model for other Micronesian states that want to better conserve their underwater life."
The survey will also include an assessment of Pohnpei's reef fishes by Dr Gerry Allen from the Western Australian Museum in August, and a survey of seagrasses by Mr Len McKenzie from the Queensland Department of Primary Industries & Fisheries in October.
The survey is a cooperative project by the Pohnpei Department of Lands and Natural Resources, Department of Economic Affairs - Division of Marine Development, Conservation Society of Pohnpei, The Nature Conservancy and Australian scientific institutions including the Western Australian Museum, Cooperative Research Centre for the Great Barrier Reef (CRC Reef) and Queensland Dept of Primary Industries & Fisheries. The survey is funded by Packard Foundation and the United States Department of Interior, Office of Insular Affairs.