Exploring Indonesia’s Mayalibit Bay Barrier Reef

Today’s blog from CI-Indonesia scientist Edy Setyawan is part of a series chronicling a joint coral reef health monitoring trip in Raja Ampat, Indonesia with CI, The Nature Conservancy and WWF. Blogs from this assessment are being cross-posted on the Nature Conservancy’s Cool Green Science blog.

Group shot of the team — made up from staff from CI, The Nature Conservancy and WWF — currently monitoring coral reef health in Indonesia's Raja Ampat archipelago.

Group shot of the team — made up from staff from CI, The Nature Conservancy and WWF — currently monitoring coral reef health in Indonesia’s Raja Ampat archipelago. (photo courtesy of Sangeeta Mangubhai)

Our 10-person monitoring team began our journey at the Mayalibit Bay marine protected area (MPA) on Waigeo Island.

This MPA covers an area of 53,100 hectares (131,200 acres) that stretches throughout the bay to the estuaries. The elongated shape of the bay almost cuts Waigeo Island in two, and the very narrow opening of the bay makes this area relatively closed off.

With its healthy mangrove forests and seagrass beds, Mayalibit Bay provides great nursery grounds for mangrove crabs and mackerel (Rastrelliger kanagurta). Mackerel is one of the most sought-after fish and is a staple in the diet of the Raja Ampat people. Aside from mackerel, the communities around the bay also harvest shrimp almost on a monthly basis.

We have explored the barrier reef around the opening of the bay that stretches from the east to the south of Waigeo Island. The purpose of monitoring this area is to assess the health of the reefs within and outside the MPA. For that, we observed the coral coverage and fish population in three different zones: the food security and tourism zone (also known as the no-take zone); the sasi,zone, which follows a traditional management practice that seasonally closes certain areas to fishing; and the traditional use zone, as well as areas outside the MPA as control sites.

Gorgonian sea fan in Raja Ampat archipelago, Indonesia.

Gorgonian sea fan in Raja Ampat archipelago, Indonesia. (© CI/photo by Edy Setyawan)

In three days, our team looked at 16 locations; six outside of the MPA, six in no-take zones, and four in traditional use zones. A comprehensive analysis is yet to be made, but early observations indicate that live coral cover varies with an average of 20% coverage. “Some are in good condition, some are not that good. Very good live coral cover can only be found at 5-7 meter [16-23 foot] depths,” said team member Ronald Mambrasar. “Rubble and algae covered coral dominate several locations near the mouth of Mayalibit Bay,” added Ismu Nur Hidayat.

Some areas have very strong currents, and here we saw many gorgonian sea fans and soft corals. “The coral composition is not very complex and diverse. But each coral reef is unique to Raja Ampat and very important to protect,” said Sangeeta Mangubhai. This type of coral can only be found in two places in Raja Ampat: Kofiau and Mayalibit Bay. Coral bleaching were also found in some branching and massive coral colonies, but not a significant amount.

Iridescent anemone on barrier reef, Mayalibit Bay, Indonesia.

Iridescent anemone on barrier reef, Mayalibit Bay, Indonesia. (© WWF/Gabby Ahmadia)

Visual observations show that several locations outside the MPA have almost the same fish population size; in fact, several locations show greater fish abundance compared to inside the MPA. We found quite a number of big fishes such as sweetlips and snappers that are more than 45 cm (18 inches).

“Compared to monitoring results in several other areas in Raja Ampat, the fish population in the Mayalibit Bay barrier reef is relatively the same,” said Purwanto. We often saw bumphead parrotfish (Bolbometopon muricatum), a bioeroder fish that measures almost a meter long. Several sharks like the gray (Carcharhinus amblyrhynchos) and blacktip reef sharks (Carcharhinus melanopterus) often keep us company in our dives around the barrier reef.

Stay tuned for more updates from this trip on CI’s blog.

Edy Setyawan is the Marine Conservation and Science Officer for the Kaimana Corridor Program, West Papua. Read other blogs from this trip.


  1. Raja Ampat says

    According to Conservation International, marine surveys suggest that the marine life diversity in the Raja Ampat area is the highest recorded on Earth. Diversity is considerably greater than any other area sampled in the Coral Triangle composed of Indonesia, Malaysia, Philippines, Papua New Guinea, Solomon Islands, and East Timor. The Coral Triangle is the heart of the world’s coral reef biodiversity, making Raja Ampat quite possibly the richest coral reef ecosystems in the world. Great trip, your article very useful for us.

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