Green colonial tunicates photographed in Raja Ampat

 

Nembrotha kubaryana photographed in Raja Ampat

Kubaryana’s nudibranch

The February/March 2017 Coral Triangle Adventures trip to Raja Ampat brought the group of intrepid snorkelers up close and personal to a stunning array of coral reef habitats, and to the myriad marine creatures that can be found in each. While these distinctive reefscapes – from clear water mangroves skirted by lush hard and soft corals to walls steeply plunging from just a few feet below the surface – each possessed its own appeal, the reef encounters in Alyui Bay, in western Waigeo, seemed to generate the most discussion. So what makes Alyui Bay so special? I could, of course, mention unforgettable encounters with tassled wobbegongs, Raja epaulette sharks, Pewter’s angelfish, seahorses, and spiny devilfish, but more than the sum of its parts, Alyui Bay allows snorkelers to experience unique assemblages of marine life in a mosaic of reef environments like no other. Beyond the allure of its more charismatic fauna, snorkelers are also awed by the kaleidoscope of colors, shapes, and patterns painted on the steep slopes they drift along. The visually rich seascape is a patchwork of hard and soft corals, sponges, and sea squirts, with colorful anthias and damselfishes hovering above the seafloor and sweetlips, butterflyfishes, and angelfishes moving among the corals below. When peering more intently into the reef, snorkelers are treated with macro life encounters typically experienced only by divers, such as brilliant yellow wentletrap snails feeding on the sun-burst orange polyps of cup corals, the glowing green fluorescence of moon corals, or the elegant hues of a splendid dottyback. But not all of the bay’s inhabitants are so flamboyant, instead living a stealthier existence – a scorpionfish donning the palette of its surroundings or a stonefish buried eyes-deep in the sand. Also notable are the large black corals that in most reef environments occur much deeper than even divers typically venture, but in Alyui Bay snorkelers have to carefully maneuver around large colonies that nearly reach the surface. These special corals, their name owing to the dark coloration of their flexible and spiny skeleton, often have lightly-colored polyps, with some especially beautiful white colonies resembling wispy, snow-dusted saplings. Snorkelers are also likely to see an abundance of my personal favorite type of marine creature…nudibranchs! These garish sea slugs are commonly found in the shallow waters of Alyui Bay, with the some of the more colorful (and relatively easy to see) sponge- and sea squirt-eating varieties frequently spotted along steep, current-swept walls.

Orange-banded butterflyfish (Cordon chrysozonus) photographed in Raja Ampat

Orange-banded butterflyfish

While I can’t claim to be an expert on the area, I suspect the rewarding snorkeling experiences of Alyui Bay ultimately result from the bay’s geology, biogeography, nutrient-rich waters, and tidal currents. The sites in Alyui Bay visited by CTA are set far enough away from the bay’s headwaters to avoid excessive sedimentation but close enough to benefit from the organic matter and nutrients that make their way into the bay through rivers that drain the vast watershed. The tidal currents gain speed as they move through narrow passes, bringing this abundance of food to the millions of tiny mouths that populate these well-fed reef communities. The steep terrain above and below the water line creates a partially shaded environment, with even less light making it into the narrower passes between the tall, steep-sided islands. Enough light is still present

Corkscrew wire coral (Cirripathes spiralis) photographed in Raja Ampat

Corkscrew wire coral

to allow a diverse community of hard corals to occur at many sites, but the usually prolific growth of branching and plating corals that dominate the more light-drenched reefs is tempered by the shade, making way for a menagerie of sponges, sea squirts and other types of shade-tolerant benthic organisms.

But all of this is really just a taste of what Alyui Bay has to offer. There is much more to discover in Alyui Bay, and with each visit snorkelers are rewarded with new, memorable experiences.

Join us for more adventures in Raja Ampat on our 2018 departures! Click here for more information.

One Comment

  • J Fravel says:

    Dave, great summary of the trip. Thanks for doing such an expert job of leading our group. Your expertise enhanced our overall experience. Raja Ampat is certainly in its own class when it comes to snorkeling. Along with all the coral, fish and beautiful colors, we really appreciated your help pointing out all the different Nudibranchs. I guess we are now officially “Nudi-nerds”.

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