This post is the last of a series about my March-April 2015 Philippines trip. I want to describe a rather impressive dive site which is not to be missed if you are diving at Mactan, Cebu — Marigondon Cavern. This was my second ever dive at this site, and my first opportunity to bring a camera there.
Marigondon cavern is located along the Mactan coast, a short boat ride from most of the dive shops. Mactan can have strong (albeit predictable) currents when the tides are changing and this spot can be particularly affected as it is a completely exposed section of the reef wall. On this occasion, Kontiki Divers staff timed it at slack tide to make accessing the cavern easier.
The cavern entrance is a huge gaping hole about 10 metres wide in the side of a vertical reef wall covered in soft corals. The top of the entrance at about 30m depth and the floor of it is a sandy slope some 10 metres below that. The arched mouth of the cavern is its most beautiful feature, especially if viewed from the inside, looking out to the blue. Is decorated with many delicate sea fans like lace. If you observe the anthias that shelter around these fans ‘hanging’ from the cavern roof, you’ll see something curious: the anthias are all swimming upside down! It did make me look twice and wonder if there was something wrong with my vision. I guess gravity is not really an issue for a tiny reef fish.
Into the cavern
Inside, the cavern is shaped roughly like the inside of a cone, i.e. it gets narrower towards the back and the floor rises. As you go in, there is an alcove up on the right-hand side to explore. The cavern is about 60 metres in length and the shallowest part inside is at about 25 metres. However it is not technically a ‘cave’, it is simply a big hole; at no point can you not turn around and see the mouth of the cavern except for a small area at the very back. Moreover, the cavern is a dead end, it is not possible to get lost inside. Nevertheless, it does have a certain atmosphere which is quite different to open water sites. It is dark, and very still and peaceful.
Inside the cavern you can see lionfish actively hunting, as they are nocturnal predators. The ones that live here must think it’s always dinnertime. I saw one going after a shrimp. Crabs, the very pretty cometfish and apparently fish with bioluminescence can also be spotted (I didn’t observe the latter though).
As the cavern is not a true cave, the site is suitable for experienced divers holding an ‘advanced’ certification; there is no need to have cave training. Don’t be misled by the pictures, is not necessary to be a tec diver like my buddy to access this site. However, using nitrox is necessary otherwise you won’t have a very long time to explore the cavern. A torch is also essential for this dive. Conditions inside the cavern are completely calm with very good visibility. It is essential to maintain good buoyancy and not kick up the fine silt on the floor of the cavern to spoil this!
The fun doesn’t end when you leave the cavern. After your ascent back up to the reeftop, you will see a curious phenomenon. It will appear as if there are hundreds of natural gas vents bubbling up from the reef! In reality, the streams of bubbles you will swim through are simply your own exhaled air that is slowly working its way through cracks in the rock in the roof of the cavern and escaping through to the reeftop above, but it does make a curious sight, like a kind of ocean jacuzzi.
Have you dived at this site? What did you think? Leave a comment below!
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