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Male Randall’s anthias. Cenderawasih Bay, West Papua, Indonesia
Burgess butterflyfish. Cenderawasih Bay, West Papua, Indonesia.
The final area of the Bird’s Head trio is Triton Bay. Located southeast of Raja Ampat on the south coast of Papua, this area has been revealed as another region rich in endemic species. In 2006 scientists mounted an exploratory expedition and found many new and indigenous species, such as Jamal’s dottyback, Nursalim flasher wrasses, and a unique walking shark. The leading theory that most likely explains the high levels of endemism around Triton Bay relates to the two large freshwater rivers that flow into the ocean to the north and south of the bay. In a similar way to the landmass-blocked mouth of Cenderawasih, the freshwater from the rivers acts as a barrier to the marine organisms in the bay. Trapped within by these walls of unsuitable habitat, the animals within evolved to suit local conditions.
Jamal’s dottyback, described in 2007. Triton Bay, West Papua, Indonesia.
The walking sharks, or epaulette sharks, are an intriguing group found around the coast of New Guinea and northern Australia. As their common name suggests, their preferred method of locomotion is walking rather than swimming. They use adapted pectoral fins to crawl around in the reef shallows to hunt for their prey. As they live in shallow water and won’t swim across deep water or unsuitable habitat, they can easily become cut off. As a result, at least six species of walking shark have evolved around the coastline of New Guinea.38 Each of the three areas of the Bird’s Head has a unique species of walking shark and there are another three in Papua New Guinea to the east. It is not beyond the realms of possibility that more species may be discovered along the New Guinean coast as scientists explore it further.
Raja Ampat walking shark. Raja Ampat, West Papua, Indonesia.
Milne Bay walking shark, described in 2010. Milne Bay, Papua New Guinea.
I have made some of my most unexpected discoveries and observations in the Bird’s Head region and experienced the bounty of the coral reef in its full splendor. I have been surrounded by such thick schools of fish that I could not even glimpse my dive buddy a few feet away. I have seen the biggest fish in the sea, the enormous whale shark, in both Cenderawasih and Triton Bays and one of the world’s smallest fish, Satomi’s pygmy seahorse, in Raja Ampat. This is truly a special corner of the world.
Male Galapagos pike blenny displaying. San Cristobal, Galapagos Islands.
Outside the Coral Triangle
Travelling outside the Coral Triangle, and to the periphery of the ocean’s coral realm, reveals reefs with their own special assemblages of creatures. When compared to the Coral Triangle these reefs can seem relatively poor in terms of species richness, but each of the different area adds to the overall richness of coral reefs globally. The limited coral reefs of the Galápagos Islands, for instance, have one-tenth the number of species as their counterparts in the Coral Triangle, but these peripheral reef locations tend to have many unique and indigenous organisms. Almost 20 percent of the marine life in Galápagos is found nowhere else on Earth. The areas with the highest numbers of such endemics are found at various isolated eastern Pacific islands, as well as Baja California, a Mexican state just south of California; Hawaii; Galápagos; the Red Sea; and Oman.39 Despite their high proportions of indigenous species, these areas all have far fewer total numbers of species than the Coral Triangle, which is blessed with both amazingly high biodiversity and many endemic species.
Red Sea anthias. Egypt.
The conspicuous angelfish is found only on the subtropical reefs of central east Australia, New Caledonia, and east to Lord Howe Island. Lord Howe Island, Australia.
Marine iguana feeding on algae. Fernandina Island, Galapagos Islands.
The more I have explored coral reefs around the world, the better my appreciation of the world’s varied reefs and how each has its own unique defining attributes. For instance, clouds of bright orange anthias fish, exuberant coral growth, and impossibly blue waters are instantly recognizable as a Red Sea reef. The Red Sea is an area of extreme contrasts. The average rainfall there is less than one centimeter per year, and barely a plant grows on the exceptionally arid land beside it. But the parched and dusty land spills abruptly into the azure sea, which bustles with life more colorful than a painter’s palette. Rather than being hindered by the desolate terrestrial landscape, the coral reefs of the Red Sea are shaped by the conditions above. The dazzling blue water is a result of the very limited rainfall, and without freshwater influx hindering their growth, the corals fringe around the land’s contours almost exactly.
Red Sea longnose filefish. Egypt.
What I most enjoy about diving the Red Sea is that 13 percent of its fishes are found nowhere else on earth.40 Over the past several million years, as sea levels have fluctuated, the Red Sea has been cut off by a land barrier at its southern reaches. It is one of the saltiest bodies of water on Earth and its high salinity drives the evolution and adaptation of its inhabitants. Huge clouds of tiny reddish anthias fish are endemic to the region; striking sunrise dottybacks and vivid orange and green spotted longnose filefish that putter about feeding on coral polyps are also indigenous.
Red Sea mimic blenny. Egypt.
Black-line fang blenny. Egypt.
Another fascinating example of evolution that exists in the Red Sea is the venomous fang blenny of the genus Meiacanthus, whose relatives have been found throughout the world’s reefs. They are quick to bite and potential predators know to avoid them, so they can largely go about their business on the reef without fear of attack. They hold a privileged position and have attracted other envious fishes wishing to exploit the situation. The Red Sea’s fang blenny is an endemic species and has a unique coloration of a blue head, black stripe, and yellow rear half of the body. Red Sea predators know to avoid these colors, so it makes sense that their mimics would need to keep up and copy these colors if they’re to successfully pull the wool over their would-be predators’ eyes.41 A harmless blenny of the genus Ecsenius mimics the venomous fang blenny, allowing it to feed on algae out in the open during the day without fear of predators. The Plagiotremus blenny also exploits the Meiacanthus, mimicking the fang blenny’s coloration to get close to fish that they themselves prey on. Predators avoid the Plagiotremus and its prey species do not fear the Meiacanthus, so they don’t worry about it being near them, allowing the mimic to approach extraordinarily closely and take a bite of a scale. I find it
