diversity, with just 240 species in the northern section compared to six hundred or so in the Coral Triangle.33 Red Sea fish life, too, although abundant, is much less diverse. Likewise, Hawaii has coral reefs, but the number of species that inhabit them is much lower than in the Coral Triangle. These patterns of coral reef biodiversity show us that the Coral Triangle has the richest reefs. Further inspection shows that within the Coral Triangle there is one area that stands out as an epicenter of biodiversity.
A picturesque coral garden. Raja Ampat, West Papua, Indonesia.
Heart of the Coral Triangle
In the remote western part of the island of New Guinea, one of the most continually rewarding areas for new species discovery remained obscured from the rest of the world until the mid-1990s. Dutch explorers named the peninsula Vogelkop, meaning “bird’s head,” due to its shape, and while today its formal name is Doberai, it’s often called the Bird’s Head Peninsula. It consists of three main areas: Cenderawasih Bay to the east, Raja Ampat to the west, and Triton Bay to the south. This region is the true heart of the Coral Triangle and the epicenter for global marine biodiversity. Of the Coral Triangle’s 605 hard coral species, 574 of them have been recorded here; some reefs support 280 species per hectare.34 By comparison, there are around one hundred hard coral species in the entire western Atlantic and Caribbean. Raja Ampat, to the west of the Bird’s Head, officially has the world’s highest coral diversity with 553 species present.35 This is incomparable across the world’s oceans and makes the area hugely important in terms of conservation.
Europeans first explored Raja Ampat in the 1800s. It is in this region that Sir Alfred Russel Wallace spent time collecting bird skins he could sell to fund his research expedition. Scientists of Wallace’s era were preoccupied with species distributions on land and largely ignored the oceans. However, in the early to mid-1800s when Europeans, including Wallace, were exploring Bird’s Head, they noted and named many common reef fishes, including widespread Indo-Pacific species such as bluefin trevally, blacktip reef sharks, and semicircular angelfish. After this initial flurry of activity, the outside world largely forgot the peninsula. This twist of fate was probably its saving grace. When modern scientists began to explore the area centuries later, they found a wilderness full of rich, pristine reefs and previously unknown species.
Two ichthyologists who have made a particularly huge contribution to the documentation of the fishes in Bird’s Head are doctors Gerry Allen and Mark Erdmann. I had the pleasure of diving with the dynamic pair in 2013 as they continued their exhaustive inventory of the Bird’s Head reefs. Dr. Allen made some of the first modern underwater scientific observations of Raja Ampat in 1998 and has returned many times in subsequent years. By 2009, when they published their Check List of species, they had recorded 1,511 reef fishes.36 They have now passed the eighteen hundred species mark and are still counting. Raja Ampat is bathed by various currents that pass through the Indonesian archipelago and into the Pacific, bringing nutrient-rich waters through the area. In addition, Raja Ampat has a huge variety of habitat types, which seems to encourage a greater number of species to inhabit them, positively impacting the high diversity of this region.
Caitlin’s dottyback, described in 2008. Cenderawasih Bay, West Papua, Indonesia.
One of the wildest locations on the planet that I have ever visited is unquestionably Cenderawasih Bay on the north coast of Indonesian Papua. Thickly forested mountains tumble into the expansive, still waters. Small villages dot the bay, and visitors must respect the local ownership of these untouched waters and receive permission from the villagers to dive the sites. On my first visit to the location, I was required to have a local national park ranger stay aboard my liveaboard vessel to aid in these exchanges. Whether it was an honest mistake, a village he should have been avoiding, or a miscommunication, I don’t know—but as we tucked into our lunch after the dive, we heard a ruckus outside. We dashed out to discover four bare-chested Papuans brandishing machetes, anger bursting from their eyes. They were livid that we hadn’t asked permission to dive the site; after all, as they saw it, we were effectively trespassing. It took some time to explain the misunderstanding and return calm. Thankfully a cold Coke isn’t easy to come by in these remote corners of the planet and they were somewhat placated by our supply. They had paddled several miles from their village, travelling in a dugout canoe, so we gave them some fuel to express our apologies, since their supply had long since run dry.
Maurine’s demoiselle, described in 2015. Cenderawasih Bay, West Papua, Indonesia.
Cenderawasih Bay is a marine biologist’s dream. It is a rare example of a location that illustrates evolution by isolation. Also known as “allopatric speciation,” Darwin saw this as the most common source of new species creation in terrestrial animals. In the same way that the Galápagos Islands are isolated from the mainland and species evolve there to suit the local conditions, Cenderawasih provides an almost self-contained ecosystem allowing for high levels of endemism. Endemism means that an organism is unique to a defined geographic region, in this case Cenderawasih Bay; although, it would also be true to say that these animals are endemic to Indonesia. The huge bay covering almost one and a half million hectares was isolated from the Pacific Ocean when large landmasses drifted across its mouth between two and five million years ago.37 These landmasses may not have created a complete physical barrier, but they were significant enough to alter currents in and out of the bay. Without this flow through, populations inside became separated from those outside the bay and over time adapted to the conditions they found themselves in within the bay.
Female ornate angelfish. Cenderawasih Bay, West Papua, Indonesia.
Diving in Cenderawasih Bay is a strange experience. While the reefs are ostensibly the same as many in Raja Ampat to the west, the inhabitants are largely alien. Bright blue and white Price’s damselfish, pink and yellow Caitlin’s dottybacks, and beige and yellow Maurine’s demoiselles are all ubiquitous here, but found nowhere else on Earth. Farther down the reef slope, the stunning Cenderawasih fairy wrasse inhabits rich coral areas at sixty feet below the surface. The shocking yellow streak and black blotches on the male’s side allow divers to spot the beauties from a fair distance away. It’s amazing that these fish remained in obscurity until 2006 when scientists first explored the bay. Previously, none of these fish were known to Western science. There are at least fourteen species of reef fishes known only from the bay, which is many more than you would expect from such a small area, with many sure to join them as it is explored further.
Male ornate angelfish. Cenderawasih Bay, West Papua, Indonesia.
While exploring the limits of recreational diving at around ninety feet, another quirk of the bay is revealed. The topographical structure of the bay means there are limited areas where the reef gently slopes into the abyss; instead, shallow slopes give way quickly to deeper drop-offs. Over the course of several ice ages, where the water level drops and subsequently rises thousands of years later, the shallow coral reef habitat was repeatedly lost and many species went locally extinct. When sea levels rose again, the lack of connectivity with areas outside the bay meant that the vacant niches couldn’t be filled by migrants. It seems that deepwater species instead seized the opportunity to fill some of these niches and moved up into the shallows. As a result, while diving in Cenderawasih it is possible to see fishes such as the alluring ornate angelfish, Randall’s anthias, and the Burgess butterflyfish in water much shallower than they are found in elsewhere in the world.
