Arthur's Rock

Arturo Abrigonda was a boatman in Batangas who became one of Anilao's pioneer dive-resort owners. He built a two-room place on the hillside above this reef in the 1980s, one account dating it to 1984, with help from a German friend, and everyone called him Arthur. He died in September 2002 and his wife Lita carried the business on. Two separate lines of telling agree on the man, and one of them is his own family's. The link from the man to the dive site is thinner: exactly one account states outright that the rock was named after him. So the person is well attested and the naming is a local story, and this page keeps the two apart. It is still more than any other named rock on this coast can offer, because nobody can tell you who Kirby was.

Between about 5 and 25 metres, with most of the dive shallower than 21, and this is the least certain number on the page. Two operators publish figures for the site and they are 5 metres apart, at 25 and 30. A third gives 70 feet or less as the ceiling for its own house-reef diving, which sits just under both. Nobody has published a logged computer profile from this reef, no survey states a dive depth for it, and the scientific collection made here carries no depth at all. There is also a maximum of 70 feet, about 21 metres, in circulation for Arthur's Rock, and it is not corroboration for anything: those are a neighbouring site's numbers, shifted one row up a chart into a blank where this site's depths should have been. The chart they were taken from leaves this site's depth column deliberately empty while giving figures for everything else it lists, which is worth more than a confident number.

Probably not, and the honest version of why is more interesting than a yes. Arthur's Rock is the holotype locality of the species, which means the single specimen that formally fixes what Chromodoris dianae is was collected here, on 17 April 1996, by a collector recorded as Jerry Allen. That is a fact about taxonomy and it promises nothing about a Tuesday. The animal is not confined to this rock either: the same scientific record lists material from Mindoro, Bauan, Cebu, Romblon and Lubang. One thing the record does not give is a depth or a position for the collection, unlike every other type specimen listed beside it, so there is no band of reef anyone can point you at. Dive it for the coral and the frogfish and treat a chromodorid as a bonus.

Divers have been arguing about that since at least 2018 and nothing has been counted to settle it. One diver who used to dive here often says there was a big swarm of bigeye trevally around the rock and thinks most of them have moved along the coast. Another reports his uncles last saw them in 2018. The diver who posted the video that started the exchange, and who dives the site, says they are still there. A first-hand account from 2026 describes schooling jacks in the shallows as a reliable feature, which is the most recent word and points the same way. Where they are said to be is consistent across all of it: shallow, at the point where the reef drops off a little. Nobody can promise them, and unlike the sanctuary a few minutes up this shore, no survey ever put a number on this school.

Half of it has, and the split is the most useful thing measured here. Twenty years after the sanctuary was declared, the coral had recovered from storm damage and past illegal fishing and was holding steady, with new growth in the shallows. Target fish, meaning the species people eat, had not improved, and species diversity had fallen. Fishing pressure from waters just outside the boundary and the possibility of poaching are named as likely reasons. A no-take line stops the boats inside it and does nothing about the boats outside it. This page gives no trend figure for target fish, deliberately: the counts recorded for 2005 and 2011 go up while a statistical test run across the same two years says they went down significantly, and picking whichever direction suits the page would be dishonest. What is not in doubt is the qualitative finding, and the single-year 2011 measurements, which put all-reef fish density and diversity here in good condition.

You can, and no. Shore access is genuinely unusual for a sanctuary on this coast and it is the reason people dive this reef two and three times in a trip, with 70-minute dives normal. The complication is the current. The one chart that grades it site by site puts this reef at moderate to strong and none of its neighbours anywhere near that, which is an odd thing to find on a dive you can walk into. The shallow shelf on a calm day is an easy dive and plenty of people learn on it. The site as a whole is graded moderate, on the current, on a working depth near 25 metres, and on visibility that gets worse the deeper you go. Look at the water before you carry your kit down.

Four sanctuaries on this stretch were rated for how well they are managed, and Arthur's came out in the middle. Twin Rocks scored 4, the top of the scale and the highest of any protected area in Mabini. Arthur's Rock and Batalang Bato scored 3. The Cathedral sanctuary scored 2, held down by fishing inside its boundaries and by having no markers or signs in the water at all. What the middle rung buys at Arthur's is visible: the boundaries are signed, so you can tell where the sanctuary is, and there are enough anchor buoys for the boats that work it. The open item is enforcement, and it is the same one the fish counts point at. Three of the four were declared in the same year under the same ordinance, and twenty years later they were not in the same condition.