Balicasag Marine Sanctuary, Bohol: Why This Reef Is Protected

Why does a tiny island off Bohol need rules for the water around it? The short answer: the Balicasag Marine Sanctuary exists because, in the early 1980s, illegal and destructive fishing was hurting this reef, and a protection programme with Silliman University started here in 1985 and 1986. Today it is a no-take, no-touch zone with daily limits on divers. The reef, the jacks and the turtles people travel for are still here because of that decision.

A small island with an unusually alive reef

Balicasag Island sits a short boat ride off Panglao, in Bohol, in the central Philippines. The island is small. The water around it is another story. Divers and freedivers come for what happens just off the beach: a coral reef that suddenly gives way to open, deep water.

That mix, a shallow reef meeting a real drop-off close to shore, is part of why Balicasag has been protected for decades. The Philippine MPA database kept by COAST says the sanctuary was set up during Silliman University's Marine Conservation Development Program in 1985 and 1986, as a response to widespread illegal and destructive fishing in the early 1980s. The same entry lists Silliman University Marine Laboratory for technical help and the Bohol Marine Triangle Project for management. These arrangements may have changed since the entry was written, so I would not assume they are the same today.

The reef is the reason everything else is here

Coral reefs are the foundation of a place like Balicasag. Corals are living animals that slowly build limestone skeletons, and those skeletons become the reef itself: a three-dimensional landscape of shelter, feeding ground and nursery for many species. For their size, reefs are among the richest habitats in the ocean.

Around Balicasag, the reef changes as you go down. It runs from a shallow, sunlit shelf near the shore to a wall that falls steeply into much deeper water. That range, from bright shallows to dim depths, packs many small habitats into a small area. Dive guides also describe a site called the Black Forest, where black corals grow at around 30 metres, although the guides I read do not even agree on which side of the island it is.

Why the drop-off matters

Deep water so close to a reef edge is not only dramatic to look at. On reef walls in general, moving water carries plankton past the reef, small fish feed on it, and bigger hunters come for the small fish. This is the general pattern for reef walls. I have not found a study that measures it at Balicasag, so please read it as plain ecology, not local data.

What you can see with your own eyes is that reef life and open-water fish share the same stretch of sea here. Dive sources describe jacks and trevallies schooling in the blue next to the wall, while turtles rest a few metres above, on the coral. That closeness is the magic of the place.

Jackfish, moving as one

Among divers, Balicasag is best known for its schools of jackfish, sometimes called a jack "tornado" for the way hundreds of fish turn and reshape themselves as one moving column. Jacks belong to the Carangidae family, the same broad group as trevallies and pompano. Schooling is a survival strategy: a tight, coordinated group makes it harder for a predator to pick out one fish.

If you come in slowly, without chasing, a school usually carries on doing what it was already doing. That is the encounter we look for anywhere: watching a wild behaviour continue undisturbed, instead of causing it. Gliding in on one breath, with no noise of bubbles, is part of why freediving suits a school like this so well, and it is the idea behind our ethical freediving retreats: observe, don't chase. A low-volume mask that seals well helps more than any fancy gear, and there is a short list of low-volume masks and snorkels in our storefront if you are still choosing.

Sea turtles on the reef

Dive sources describe sea turtle encounters at Balicasag as common. The turtles here are usually seen resting on the reef or feeding. I did not find a survey that says which species are most frequent, so ask your local guide; they know their turtles better than any website. And as with any wild animal, nothing is guaranteed on a given day.

The rule is the same as everywhere: keep a respectful distance, let the turtle decide, and never touch or chase. A resting turtle that is pushed to swim away uses energy it did not plan to spend. Wildlife encounters are unpredictable. Snorkelling and diving with sea turtles should always follow local regulations and experienced professional guidance. We go deeper in our piece on snorkelling responsibly around turtles.

What does the protection actually do?

A marine sanctuary does not close the water to people. At Balicasag, travel and dive sources describe the sanctuary as no-take and no-touch across the zone, with guides required. On paper that sounds modest. In practice, over decades, protection from fishing is what lets a reef keep its big fish and its structure.

But a sanctuary only works if it is respected every day, and popularity brings its own pressure: many boats, many fins, many hands near coral. That is why the visitor rules matter as much as the fishing rules. Research on protected areas in general shows that results depend on enforcement and management, not only on the label. We looked at that evidence in whether marine protected areas actually work. For a visitor, the ethical part is simple: do not touch, do not stand on coral, keep your fins high, and choose an operator who follows the rules even when nobody is watching.

Sunscreen is part of this too. Covering up with a rash guard means less cream in the water, and if you do use cream, a mineral formula is the usual advice; we keep a list of mineral sunscreens if that helps your packing.

How visiting Balicasag works today

Several dive and travel sources describe the same system: Panglao's local government limits Balicasag to about 150 divers a day, with a maximum of two dives per diver, and dives are booked in advance through accredited dive operators on Alona Beach. The operator files a reservation form for each diver and collects an environmental user fee, most often quoted at around ₱250 per diver per day. Other sources quote a different sanctuary fee, and I could not find the rule on an official government page. So please treat these numbers as reported, not confirmed, and check the current rule with your operator or the Panglao municipality before you travel.

The boat ride out is short but often splashy. A roll-top dry bag keeps a phone and a towel dry, which is one less thing to think about while you listen to the briefing.

What Balicasag teaches about the ocean we love

Everything people come to Balicasag for, a living reef wall, jacks moving as one, turtles resting on the coral, exists because the ecosystem has been given room to stay healthy. Decades of local protection are a big part of why such a small island still holds this much life, a short swim from shore.

The honest part: our visits are also pressure, and flying to the Philippines has a real carbon cost. The least we can do is arrive slowly, follow the limits without complaining and leave the reef exactly as we found it. You can read more about the country on our Philippines Ocean Atlas page. If this made you curious about experiencing the ocean this way, you can explore our retreats.

Questions people ask

Wildlife encounters are never guaranteed and never forced. Ocean Calling works only with vetted, ethical local operators, and every animal is free to approach, or not, entirely on its own terms.