Hello all,
This video by Dr. Phil Dustan was posted on the Bird's Head Seascape network, and I thought some might be interested.

Continuing coverage of the Raja Ampat Coral Bleaching Event: "Caught in the Confluence of Global Warming and Ecotourism".
 

In October 2024, a marine heatwave struck the iconic coral reefs of Raja Ampat.
Corals in the Dampier Straits experienced severe bleaching and mortality, fueled by increasing levels of sewage from rapidly expanding ecotourism. Unless the sewage threat is eliminated, the World’s richest reefs and the economy they support will collapse.

*****

It's good to see sewage/waste water finally mentioned so clearly. Development-related run-off, silting and pollution have been an issue on house-reefs for a while in certain areas.

On a personal note, I remember seeing the change betwen 2014 and 2017 (which was my last visit to Central RajaAmpat / Dampier Strait), with house-reefs being seriously affected in the Mansuar (Besar and Kecil/Kri) area. 2016-2015 was a massive turning point, with lots of homestays built in the area which once only hosted Max Ammer's Kri-Eco and Sorido resorts, and very fast.
Trees near the shoreline were cut, structrues were built (there was even a plan to build a pool at some point...) and in only a few months you could see silting and algae growth in the shallow "house-reefs" around the island, linked to run-off from from rainwater no longer held by the treeline and also waste water from the new infrastructures (notably showers and toilets)...

Coral colonies in the area are/were believed to have evolved to better withstand heat-stress (not sure where the research on the subject is at now), but combined with stress from infrastructure and activity development, it's quite a lot.
Add to that snorkeler/diver damage (seeing an overweighted "discover-scuba diver" smash a table coral in front of my eyes at Yenbuba, or the growing effect of fin-kicks-and-chill on the often current-swept top of a site like Blue Magic come to mind...) to the now unavoidable global emission-related emergency (difficult to reach Raja Ampat without flying to Sorong from somewhere, unfortunately...), trash, plastic, oil and the rest (no, let's not talk about that cruise-ship smashing into the reef at Crossover...) and there are a lot of reasons to be worried for what is still often marketed as "The Last Paradise©"

It's something that also struck me in less remote areas like Bali's booming Amed for instance, where over-construction and associated waste-water is rapidly killing of what is left of the reef in the area.

What was that saying about being in traffic or being traffic again? 😐

cheers

ben

Edited March 4Mar 4 by bghazzal

We were in Raja in January and in the North there was a ton of bleaching of corals and anemones. In the south (Misool) not so much but it was warm (31C)

Bill

This is very sad news, thanks for posting ...😢

Is there a scientific study available on the Raja Ampat bleaching event, especially on the role of sewage in coral bleaching and dying?

 

I returned yesterday (March 22nd, 2025) from diving vacations in the Red Sea (Egypt/El Quesier area). Last stay there was in September 2023 and the coral still looked reasonably intact and little influenced by record heat and bleaching at this last stay, suggesting that Red Sea coral is pretty heat resistent...

 

=> The diving this time was sobering and really heart breaking (I dive in the Red Sea since the 80ies and have to face now this diving paradise vanishing): substantial amounts of hard coral (but also fire corals (which are not corals but hydrozoans)) dead and covered with algae (similar as in the video above by Dr. Dustan). Fish population greatly decreased, indicating that the entire ecosystem is out of joint ... 😞

 

 

Wolfgang

 

 

Edited March 23Mar 23 by Architeuthis

I am not aware of any scientific papers on coral bleaching in Raja other than the study from Indo-Ocean project, Lauren Sparks. They speculate that a major increase in cyanobacteria linked to human sewage. As tourism increases and toilets move ever closer to the water, the filtration of sewage by the soil is greatly decreased.

 

Bill

eI am not aware of any scientific papers on coral bleaching in Raja other than the study from Indo-Ocean project, Lauren Sparks. They speculate that a major increase in cyanobacteria linked to human sewage. As tourism increases and toilets move ever closer to the water, the filtration of sewage by the soil is greatly decreased.

On 3/24/2025 at 6:21 AM, bvanant said:

 

Bill

Here's an article published in Oceanographic on tracking rising cyonabacteria levels in Raja4's Arborek island:

https://waterpixels.net/forums/topic/2353-article-trouble-in-paradise-rising-cyanobacteria-levels-in-raja-ampat/

Edited April 30Apr 30 by bghazzal

We are in Misool right now, a fair bit of bleaching, but no where near as bad as Dampier at Christmas

Bill

I could have waved to you, Bill. We sailed out of Misool yesterday. Fabulous diving.

We are on the Welleneeng, today we did Nudi Rock, Whale Rock and Wedding Cake. On the way to Kaimana/ Triton Bay

Bill

There is this study on Raja Ampat's coral bleaching in the Oceanocaphic Magazine:

https://oceanographicmagazine.com/features/cyanobacteria-in-raja-ampat/