Indonesia — Raja Ampat
Raf's Reef Brief
West Dampier Strait
Visited December 23-31st, 2025
Written September 9th, 2026
This Reef Brief covers the northwestern portion of the Dampier Strait, from the westernmost Pulau Arborek to the village Yenbekwan on the east side of Pulau Mansuar. To instead see our coral condition report on the areas around Pulau Kri & Yenbuba in the northeast portion of the Dampier Strait, please click here.
The Dampier Strait lies between the islands of Gam to its north & Batanta to the south, and encompasses a large array of limestone islands, cays, & patch reefs. Located at the entrance of the Indonesian Throughflow, the Dampier Strait is constantly inundated by powerful warm ocean currents from the Pacific Ocean that drive a complex web of water exchanges between its islands. This effect is only amplified by the maze of patch reefs and sand cays located in the northwest quadrant of the strait. The result is a collection of exposed & protected coral reefs fueled and connected by deep nutrient-rich upwellings.
This combination of geology, oceanography, and temperature is responsible for the explosion of underwater diversity and life that Raja Ampat is known for, and the Dampier Strait is popularly regarded as its epicenter. Exposed slopes coated in dense colonies of Isopora brueggemanni can be found on the same patch reef as gardens of lush Goniopora & Heliopora nestled in sheltered bays
Diverse Acropora 'heaven' in the West Dampier Strait— How many species can you count in this single photo?
Unfortunately, the West Dampier Strait is part of the core of tourism in Raja Ampat. Hordes of irresponsible tourists flock to the area to see ‘The Last Paradise’— where they feed fish, stand on corals, or chase mantas. Meanwhile, marine heatwaves continue to increase in frequency & severity due to human driven Climate Change. But worst of all, clusters of homestays line every available shore while dozens of liveaboards navigate waterways, (directly & indirectly) releasing untreated sewage into the water column. The amount of waste released in the north portion of the Dampier Strait is estimated by some to be equivalent to a city of ~70,000 residents.
Prior to the 2020's, the effect of these factors was only noticeable in the form of limited nutrient indicator outbreaks. But in November 2024, due to a severe marine heatwave compounded by increased coral vulnerability from the sewage crisis, the Dampier Strait endured its FIRST mass bleaching event in recorded history. An area, once hailed as a spot of hope compared to reefs elsewhere in the world, underwent mass destruction it had previously been resistant to. The Dampier Strait was the hardest hit, with the western area less affected than the east which had significantly more homestays. But don’t get too excited- significant Crown of Thorns Starfish (COTS) outbreaks in the west finishing the job.
As if that wasn't bad enough, 2025 was not quite a year of recovery for the hard corals here. Starting in December 2025, we witnessed very mild bleaching of select colonies around the West Dampier Strait. With a super El Niño predicted for late 2026, I can't help but feel this area is doomed.
Some reefs near human development, like the reef flat east of the famous Sawandarek Jetty, bear large amounts of recent mortality, mild bleaching, and nutrient indicators
After the last four regions we reviewed around Raja Ampat, no amount of destruction was going to phase me - the Fam Islands and more so the East Dampier Strait did a great job of shattering my hopes for endless thriving hard corals. Yet surprisingly, the West Dampier Strait was in better condition than those two locations. Sure the scars of the 2024 Mass Bleaching Event & constant unethical tourism are everywhere to be found, but on average, I feel this location still showed healthier and more expansive hard coral cover. Given the active degradation by COTS, slope destabilization, & nutrient indicators were present at almost every site, this may not be the case for long
I would recommend the West Dampier Strait’s hard corals for diving/snorkeling and conservation/research, but only once liveaboard and homestay sewage output is regulated across the region. Otherwise, this area will end up just as degraded as its eastern counterpart.
Walkthroughs of the West Dampier Strait
Surveying the reefs of the West Dampier Strait was considerably easier than other areas in Raja Ampat. While environmentally devastating, the plethora of homestays new & old provided reasonable access to most sites. However the lack of dive boats, high local cost of fuel, and strong unpredictable currents significantly strained our site selection. The lack of information on the reefs in the northwest region specifically didn't help either. As a result we chose to only snorkel target sites for greater flexibility & range.
Nonetheless, we reviewed 13 sites from December 23rd to 31st for hard coral health, whose walkthroughs and data can be viewed below. Some sites may have their names, coordinates, and maps censored if the corals are deemed too vulnerable to be shared with the public.
Sites Table of Contents
Site One
December 23
Despite being consistently dominated by Isopora brueggemanni, Site One still presents significant diversity—such as the 11 hard coral species in this photo
Site One is a 1.5-kilometer-long northward fringing reef that is jagged in shape and experiences strong parallel currents. The topography consists of a ~1m deep reef flat that gives way to an upper fore reef slope, both with variable hard coral cover. Beneath that, starting at ~5m, is a sandy slope that culminates in a plateau beyond ~12m deep. The reef is generally dominated by Isopora brueggemanni, with occasional Acropora or Isopora palifera stands, depending on exposure. There is significant human development nearby so it shouldn't be a surprise that there is mechanical damage and many nutrient indicators present, particularly carpets of photosynthetic sponge. There is also a large amount of mild coral bleaching, recently deceased colonies, COTS, and large rubble ruts in the matrix in all zones. Currents ranged from very strong to moderate and visbility was almost always very high.
This was the very first site we entered in the entire Dampier Strait after the high cover reefs of West Waigeo, and it was a bit of a gut punch with all the recent degradation around. However, in retrospect, it was certainly a lot higher in cover than anything we saw later in the east side of the strait (even if this site had just as much mortality & bleaching).
Site One Site Walkthrough
Site One Site Data
Site Two
December 27
Select colonies among a fore reef of Isopora brueggemanni, partially bleached after being subjected to abnormally high temperatures
Site Two consists of a semi-exposed fringing reef and its very wide shallow reef flat, hard coral dominated upper fore reef, and a rubbly slope that descends into the blue. For the most part, the hard coral cover on the lower slope & on top of the reef flat is either nonexistent or very degraded. The same is usually true for the top of the upper fore reef in the final third of the site, but outside of that, the live coral cover on the upper fore reef is high and dominated by Isopora brueggemanni. Small amounts of bleaching and many nutrient indicators such as photosynthetic sponge are present. Large fish were present throughout the site. Currents ranged from very strong to mild & visibility was always high.
Site Two is very similar to the first sites of both Dampier Strait briefs due to the shared topography, fairly degraded coral condition, and of course the shared dominant species. Consequently, I feel pretty much the same way about this site. It wasn't the healthiest, it wasn't devastated, but it was full of my favorite coral so I guess I can't complain.
Site Two Site Walkthrough
Site Two Site Data
Sawandarek Jetty
December 29
Shallow coral colonies undergoing a mild bleaching event at Sawandarek, minor in comparison to the Mass Bleaching Event in the region a year prior
The very famous Sawandarek Jetty is one of the most visited sites in Raja Ampat for snorkelers & divers, so unsurprisingly there are a number of homestays in the settlement. The jetty sits over a gradual fore reef slope that ends in a sandy plateau, with a long fringing reef to its north. Live coral cover is usually restricted to the upper fore reef slope and reef flat, with the exception of some bommies & an Acropora matrix on the sandy bottom. Despite high fish biomass, the coral cover is very degraded with large sections of recent mortality and notable amounts of disease, active bleaching, nutrient indicators, & even some COTS. Currents were mild to nonexistent and visibility was always high below the surface.
I came to Sawandarek with low expectations due to the reports of high coral mortality following the Mass Bleaching Event last year—and while it wasn't as apocalyptic as I expected, it was still hard to see. The fish were as advertised though, that was pretty cool.
Sawandarek Jetty Site Walkthrough
Sawandarek Jetty Site Data
Site Four
December 29
A monoculture of branching Acropora creates an illusion of rolling hills at Site Four
Site Four is a fringing reef consisting of a wide, gradually sloping outer reef flat that drops off onto a rubble slope ~4-5m deep which bottoms out on a deep sandy plateau. The fore reef slope is very degraded, as is the reef flat at either end of the site. But in the center of the site, there is a large semi-continuous matrix of very high Acropora dominated hard coral cover in mixed condition. Mild bleaching of select colonies, nutrient indicators, disease, and rubble ruts are present in the matrix. Visibility was moderate and currents were mild.
We visited this exploratory site on a whim after seeing some potentially high cover from the surface... and we were right! Even though there were plenty of ruts & active bleaching, it was awesome to see such a broad Acropora matrix after the last week. I sincerely hope that this minor bleaching even doesn't create too much mortality so it can continue to grow in an otherwise devastated area.
Site Four Site Walkthrough
Site Four Site Data
North Arborek
December 29
Lush patches of tabling & branching Acropora grow in the sandy flats around the northern tip of Arborek
The ever popular Pulau Arborek is a small coral island populated by a village and developing homestay industry. There are currently at least 8 different homestays lining the shores, mostly in the south, and two famous jetties in the north that attract many daytrips. The island's semi-exposed northeast side, stretching from the eastern to north tips, generally consists of variable width reef flats atop sandy sloping fore reefs. Hard coral cover and condition vary greatly but are generally good & diverse. Fish life is great, though nutrient indicators, active mortality, & predation are all present. Currents were very strong to moderate & visibility was very high until the last dozen meters.
The north coast of Arborek pleasantly surprised me when compared to the hard coral cover surrounding the jetties at Yenbuba, Sawandarek, & Kri. Despite a very high & localized source of sewage, negative indicators and mortality are relatively low here... for now. As we'll soon find out, South Arborek wasn't so lucky, and if development continues, the north might be next!
North Arborek Site Walkthrough
North Arborek Site Data
Southwest Arborek
December 29
The high flow rubble fields like those of southwest Arborek, too destabilized for hard coral resettlement, are easily overtaken by the soft corals Sarcophyton crassocaule
Southwest Arborek's exposed fringing reef consists of a shallow reef crest & reef flat above a gradually sloping fore reef. The hard coral cover is abysmal with the fore reef almost entirely consisting of rubble smothered in various soft coral genera, usually Sarcophyton, while the reef crest fluctuates between scrappy and utterly deceased. Reports by local organizations indicated that the area underwent a phase shift to a soft coral-dominated state only within the last few years. The hard corals that do remain are usually small stands of branching Isopora brueggemanni on the slope and columnar Isopora palifera on the reef crest. Drupella, disease, and nutrient indicators were frequently present. Currents were strong to moderate & visibility was high.
I don't know what destroyed Southwest Arborek... storms, disease, Drupella, blast fishing, etc. But regardless, what seems to have been extensive fields of Isopora brueggemanni, like those seen elsewhere in Raja Ampat, are long-gone. R.I.P. bruegg, you'll always be my favorite species.
Southwest Arborek Site Walkthrough
Southwest Arborek Site Data
South Bunibah
December 29
The remaining stands of Isopora brueggemanni at Pulau Bunibah suggest that the site's vast rubble fields may have once been dominated by this prolific species
The center of the southern fringing reef along the limestone resort island of Pulau Bunibah consists of a very wide, shallow reef flat above gradual slopes. The site is almost completely a giant rubble field with some degraded but live stands of Isopora and branching Acropora remaining on the deeper slope & upper fore reef. There is plenty of human waste, nutrient indicators, and soft coral monocultures on the rubbly substrate. Currents ranged from moderate to low and visibility was only ever okay.
This site was just depressing. Almost a kilometer of rubble and scrappy survivors—not too surprising considering the destruction in our last four briefs about Raja Ampat. But in the contemporary Dampier Strait, if you choose sites based off of ecological cues rather than known hard coral holdouts, some reefs are bound to be found devastated.
South Bunibah Site Walkthrough
South Bunibah Site Data
Site Eight
December 30
Isopora palifera's thick columns are adapted to absorb breaking waves at the semi-exposed Site Eight
Site Eight is the southward, semi-exposed side of a large sandy patch reef. The entire site consists of a wide and sandy outer reef flat that gently slopes into the upper fore reef, which drops off into sandy slopes of varying steepness. All zones were generally low in hard coral cover, save for some stands of Isopora palifera and various other genera, and the coral cover present often includes small amounts of active mortality. An online source states that the area was historically impacted by nearby fish farming. Currents were weak and visibility was very high.
Findings from the same online source indicated that this site would be high in hard coral cover. Clearly, they must not have been talking about this specific kilometer of coastline, because there weren't any impressive hard corals above or below. Whatever happened to the coral cover here seems to have been a long time ago.
Site Eight Site Walkthrough
Site Eight Site Data
Site Nine
December 30
The clear but calm & protected waters of Site Nine create a special environment where a diverse array of fragile & robust hard coral genera thrive
Site Nine is a protected, wide, & deep bay with three sides and a deep sandy plateau at its bottom. The sides of the bay consist of very gradual slopes below shallow reef flats. Hard coral cover varies greatly, with some sections very high & diverse from top to bottom while others are destabilized and choke out by soft corals/nutrient indicators. A mild COTS outbreak is also present. The site is dominated by a wide variety of genera, including Pavona, Anacropora, Montipora, Isopora, and more. There is no human activity now but reports indicate that there was historically. Visibility was consistently above average and currents were nonexistent.
When the online masses talk about the diversity of Raja Ampat, Site Nine is exactly what I imagined: massive sections of all of my favorite hard coral genera smashed together & tucked inside a sheltered little bay. There was indeed a lot of devastation past and present, but between the excellent remaining colonies and the rapid desensitization to coral degradation that Raja had put me through thus far, I loved this site. I hope it's not all eaten up by COTS when I return with scuba gear!
Site Nine Site Walkthrough
Site Nine Site Data
Site Ten
December 30
Plating Montipora dominate the start of Site Ten's semi-exposed reef flat, thanks to its thick horizontal growth form that can withstand high energy environments
The north-to-south fringing reef that is Site Ten faces strong westward flow and consists of a ~2m deep reef flat, sloping upper fore reef, and sandy slope below. The northern site is quite exposed and features high Montipora & Isopora coral cover on the outer reef flat and upper fore reef with sporadic bommies on the sandy slope. The southern portion is more protected and is dominated by branching Acropora, though cover outside of the reef flat is low. There is human presence in the area and as such there are signs of nutrient indicators & mechanical damage, alongside disease, COTS, and a minor bleaching of select colonies. Currents were strong in the north and minor to the south with very high visibility until the end of the site.
I've gotta admit, the outer reef flat here was quite beautiful. The sections of continuous coral cover were generally small and surrounded by battered colonies, but I'd be lying if I said that they weren't diverse & gorgeous. Let's just hope that the development around here doesn't finish them off!
Site Ten Site Walkthrough
Site Ten Site Data
Site Eleven
December 31
The fields of Goniopora lobata at Site Eleven are the most impressive I've ever seen this genus form
Site Eleven's unique high flow environment is the result of its channel-like patch reef formation. Its topography typically includes a very shallow scrappy reef flat above Isopora brueggemanni dominated upper fore reef slopes which give way to bare sandy slopes & plateaus below. However, there are some areas with diverse cover in the deeper zones, as well as large & unique stands of Goniopora lobata in the shallows. Some areas are totally destroyed & the cover is frequently destabilized. Large amounts of fluorescence, partial mortality, & nutrient indicators are present. Currents started strong but became non-existent and visibility was generally high.
Okay, say what you want about my inconsistent opinions, but I adored Site Eleven. Were huge areas in terrible condition, particularly the stands of I. brueggemanni? Totally—but those Goniopora fields—wow! Since this site was exploratory, I came up with the name "Gabe's Gonis" after a relative. This was due both to the unusual coral cover & the fact that it sounds like "Gabe's Gonads"... lol.
Site Eleven Site Walkthrough
Site Eleven Site Data
Site Twelve
December 31
Delicate Montipora hodsgoni can grow large & upright when protected, like at the bottom of Site Twelve's sandy bay
The inside of the small sheltered bay that is Site Twelve sits on the outside of a large patch reef and generally consists of steep slopes that begin under very shallow reef flats and end above a sandy plateau. The coral cover is generally decimated with a decent amount of live cover remaining, though it is usually bleached, diseased, or surrounded by nutrient indicators & soft corals. One exception is the right side where the hard coral cover is high and diverse, though it was generally destabilized & fluorescing. Currents were non-existent and visibility was okay.
At first, this site was really disappointing with large fields of smothered rubble & bleaching colonies. There is no but—this site was pretty meh. At least the destabilized assemblages of hard corals later on were diverse and (hauntingly) colorful.
Site Twelve Site Walkthrough
Site Twelve Site Data
Site Thirteen
December 31
Even amidst a Crown of Thorns Starfish (COTS) outbreak, extensive stands of foliose & branching hard corals still survive across Site Thirteen's deep slopes
Site Thirteen consists of the eastern corner & northward edge of a long patch reef in a high flow environment. The eastern corner begins as a 10m+ deep sheltered channel and the northward side consists of steep, deep slopes. The substrate in the channel is mostly rubble & sand with some areas high in hard coral cover, whereas the north side is dominated by varied hard coral cover in all zones. The high cover areas on this north side are usually dominated by foliose Montipora, with large stands of Acropora, & a reef flat full of Galaxea as well. There is a moderate COTS outbreak present in the deeper slope, and significant areas are deceased or destabilized. Currents ranged from very strong to moderate & visibility from average to very high.
This site was tragic—not because of the COTS outbreak & slope destabilization present (which are tragic in a different way), but because my camera ran out of storage towards the end of the site. This meant that I didn't capture the giant manta ray that surprised us before we exited the water... oh well. Between the awesome assemblages of corals remaining & the manta sighting, this site was an awesome finale to not only the West Dampier Strait or Raja Ampat, but also our entire 2025 expedition.
Site Thirteen Site Walkthrough
Site Thirteen Site Data
How to Visit the Corals of the Western Dampier Strait
Like with many of the locations on this website, and in Indonesia in particular, visiting the hard corals of Raja Ampat is quite the challenge. The usual woes of getting to the region, planning one's logistics, bringing the right gear, and having the in-water skills required are tough here. Finding sustainable dive & snorkel operators who will accompany you to the specific sites & depths with the highest coral cover can be even harder.
Lets focus in on that last sentence— sustainable. It's no secret that the dive & snorkel travel industries (and to a lesser extant, all travel in general) have an undeniable negative impact on hard coral environments. This is especially applicable in Raja Ampat, where largely unrestricted tourism has caused near-irreversible harm via sewage, mechanical damage, and development.
Absolutely no one who isn't contributing to the conservation of these reefs in a significant way should be visiting if their visit are causing measurable harm to the integrity of the ecosystem present. This is something I take very seriously which will be reflected in the recommendations below. If sustainable means are not present, this section will be unavailable indefinitely.
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DISCLAIMER: This blog post does not constitute scholarly research, nor is it partnered with or associated with any scientific research, institutions, journals, publications, or scholars. All observations are qualitative and informal, observed during standard recreational activities without accordance with scientific norms, methods, accreditation, training, or procedures. These observations are presented only as blog posts intended for environmental enthusiasts on Rafsreefbrief.com. All blogs and observations are not submitted to nor meant for use by any scientific publications or purposes, and are not meant to support any scientific truth, conclusion, profit, or technology. Observations are only valid at time of occurrence. All opinions expressed are our own. We are not liable for any damages or losses resulting from the use ore reliance of information contained on Rafsreefbrief.com or its media accounts. Seriously people, this is just an environmental-travel hobby & blog, nothing more!